Electrical Engineering Glossary (English with Sinhala Terms) - විදුලි ඉංජිනේරු ටීකාව (ඉංග්‍රීසියෙන් - සිංහල පද සමග)

Prepared by Professor J R Lucas (© copyright reserved)

This site was originally launched at the Department of Electrical Engineering,University of Moratuwa on 11 December 2001. Sinhala terms included in October 2019.
I would be grateful for any amendments, suggestions or additions to the glossary, so as to benefit the users. email: This email address is being protected from spambots. You need JavaScript enabled to view it.


English Termsසිංහල පදDescription
A මුලට TOP
a c potentiometer ප්‍ර.ධා පොටෙන්ටෝමීටරය (විභවමානය) An instrument for the measurement of a.c. voltages by comparison.Requires balancing of both the magnitude and the phase angle of the unknown voltage with that of the known voltage. May be done either in cartesian form or in polar form.
a.c. - d.c. converter ප්‍ර.ධා. - ස.ධා. පරිවර්තකය AC-DC converters are electrical circuits that transform alternating current (AC) input into direct current (DC) output. They are used in power electronic applications that require power conversion for a DC output.
a.c., alternating current ප්‍ර.ධා. (ප්‍රත්‍යාවර්ත ධාරාව) A current whose instantaneous values reverses in regularly recurring intervals of time and which has alternative positive and negative values, the cycle being repeated continuously. The term is commonly used to refer to sinusoidal waveforms.
a.c. bridge ප්‍ර.ධා. සේතුව (ප්‍රත්‍යාවර්තක ධාරා සේතුව) An AC bridge has four arms, an AC supply source and a balance detector. May need balancing with 2 variable elements. Such bridges are used for measuring the values of unknown resistance, inductance and capacitance to give accurate results of the measurement.
absolute unit නිරපේක්ෂ ඒකක a unit of measurement which is defined in terms of the fundamental units of a system (base units), and is not based on arbitrary or independant definitions.
absolute value නිරපේක්ෂ වටිනාකම Value of an expression without regard to sign or phase angle.
absolute zero නිරපේක්ෂ ශුන්‍යය The temperature where thermal energy is at minimum. -273.15°C or 0 Kelvin.
acceleration ත්වරණය Rate of change of velocity. [Unit: m/s2]
acceleration due to gravity g ගුරුත්වාකර්ෂණය හේතුවෙන් ත්වරණය Acceleration of a body falling freely in a vacuum as a result of the gravitational pull of the earth. g = 9.807 m/s2
accessory උපාංගය A device, other than current using equipment, associated with such equipment or with the wiring of an installation.
accumulator සමාවායකය (ඇකුමුලේටර්) Storage battery or secondary cell for storing electricity.
accuracy නිරවද්‍යතාවය Specifies the nearness of the measured value from the true value.
acid අම්ලය Containing an excess of hydrogen ions over hydroxyl ions.
acoustics ධ්වනි විද්‍යාව Study of sound. Deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
acre අක්කරය Unit of area in the Imperial system. 1 acre = 4047 m2 = 0.4047 hectares
active element සක්‍රීය මූලද්‍රව්‍යය An element capable of generating electrical energy.
active filter සක්‍රීය පෙරණය Any filter using an op amp is called an active filter.
actuator ඔදයනය Mechanical part of a limit switch that uses mechanical force to actuate the switch contacts.
acute angle සුළු කෝණය An angle of less than 90o.
adaptor අනුහුරුකුරුව; අනුවර්තකය A device for connecting pieces of equipment that cannot be connected directly.
address ලිපිනය The number that uniquely identifies the location of a word in memory.
adequacy ප්‍රමාණවත් Ability of the electric system to supply the aggregate electric demand and energy requirements of the consumers at all times, taking into account scheduled and unscheduled outages of system facilities.
adiabatic ස්ථීරතාපී (ඇඩියබැටික්) A process taking place without heat entering or leaving the system.
admittance ප්‍රවේශ්‍යතාව (සම්බාධනයෙහි ප්‍රතිලෝම) Ratio of the electric current to the voltage. Reciprocal of impedance. [Unit: siemens or S]
aerial ඇහැසිය; ගුවන් කම්බිය A rod, wire, or other structure by which signals are transmitted or received as part of a transmission or receiving system.
aerodynamics වායුගති විද්‍යාව Study of air moving around solid objects, or air flowing around a stationary structure.
affinity බන්ධුත්වය, රුචිය The degree to which a substance tends to combine with another.
ageing විය යෑම; වියැයීම Ageing does not always correspond to the chronological age.
agent නියෝජිත, කාරක A person or business authorized to act on another's behalf. Also, an embedded program that runs on or near an IoT device and reports the status of some asset or environment.
air conditioning වායුසමීකරණය The control of temperature, humidity and the purity of the air. In tropical countries like Sri Lanka, air conditioning only cools the air and not heats it, but in cold countries both modes are available.
air gap වා හිඩැස An air-filled gap in a magnetic or electric circuit.
algebraic sum වීජීය එකතුව Total of a number of quantities of the same kind, with due regard to sign.
algorithm ඇල්ගොරිතම (ගණිතයේ එන විශේෂ රීති ක්‍රමයක්) A systematic mathematical procedure which enables a problem to be solved in a definite number of steps.
alkaline ක්ෂාරීය Containing an excess of hydroxyl ions over hydrogen ions.
alloy මිශ්‍ර ලෝහය A composition of two or more metals.
alphanumeric අක්ෂරාංක The collection of numbers, alphabetic characters and symbols.
alternate sweep වරක් ඇර වරක් හරහාට යෑම A vertical mode of operation for a dual-trace oscilloscope. The signal from the second channel is displayed after the signal from the first channel. Each trace has a complete trace, and the display continues to alternate.
alternating current, ac ප්‍රත්‍යාවර්තක ධාරාව A current whose instantaneous values reverses in regularly recurring intervals of time and which has alternative positive and negative values, the cycle being repeated continuously. The term is commonly used to refer to sinusoidal waveforms.
alternator ප්‍රත්‍යාවර්තකය, විදුලි ජනකය A machine (generator) for producing alternating currents or voltages.
ALU, Arithmetic Logic Unit අංකගණිත තර්ක ඒකකය arithmetic logic unit - A digital circuit used in computers to perform arithmetic and logic operations.
anomaly අනියමය Something that deviates from what is normal, or expected
arithmetic progression අංක ගණිත ප්‍රගතිය A series of quantities in which each term differs from the preceding term by a constant difference.
armature ආමේචරය The coil or coils of an electric motor or generator or of an electric apparatus in which a voltage is induced by a magnetic field.
armoured cable සන්නද්ධ කේබලය (?), කැවසූ ‍යොත (?) Cable with a metal protective covering.
arm's reach අත ළඟ A zone of accessibility to touch, extending from any point on a surface where persons usually stand or move about to the limits which a person can reach with a hand in any direction without assistance.
arrester නිවාරකය A device placed from phase to ground, or phase to phase, whose nonlinear impedance characteristics provide a path for high-amplitude transients.
asymmetric අසමමිතික Not possessing symmetry. Unequal distribution about one or more axes.
asymptote ස්පර්ශෝන්මුඛය a straight line that continually approaches a given curve but does not meet it at any finite distance
asynchronous අසමමුහුර්තක Not synchronous. Especially used with electric machines to denote that the magnetic field and the rotation are not exactly the same.
atmosphere වායුගෝල (ඇට්මොස්ෆිය) Unit of pressure corresponding to standard atmospheric pressure. It is taken as the pressure that will support a column of mercury 760 mm high. It is also equal to 1.013 * 105 pa
atomic mass unit, amu පරමාණුක ස්කන්ධ ඒකකය Unit used for expressing masses of isotopes of elements. 1 a.m.u. = 1.661 x 10-27 kg
attenuation භායනය Loss of signal power or amplitude suffered during its transmission through a medium.
attenuator හායකය A passive device used to reduce signal strength.
atto (a) අ​ට්ටො Decimal sub-multiple prefix corresponding to 10-18
audio amplifier ශ්‍රව්‍ය වර්ධකය (ඇම්ප්ලිෆයර්) An amplifier designed to be used in the audio range of frequencies.
audio frequency ශ්‍රව්‍ය සංඛ්‍යාතය A frequency corresponding to audible sound waves, and thus corresponds to a frequency between 20 Hz and 20 kHz.
automatic transfer switch ස්වයංක්‍රීය ස්විචය A switch that automatically transfers electrical loads to alternate or emergency-standby power sources.
automation ස්වයංක්‍රීයකරණය The application of mechanical or electronic techniques to minimise the use of manpower in any process.
autonomous ස්වයං පාලක The ability to function in an independent manner. An autonomous robot is a robot that performs behaviors or tasks with a high degree of autonomy.
autoreclose ඉබේ නැවත වැසීම A feature of certain circuit breakers where they close automatically after a predetermined time after an automatic opening due to a transient fault.
autotransformer තනිදඟර පරිණාමකය A transformer in which both the primary and the secondary windings share common turns. It provides no isolation.
autotransformer starter තනිදඟර පරිණාමක ක්‍රියාරම්භකය A starter that includes an auto-transformer to furnish reduced voltage for starting an alternating current motor.
auxiliary contacts සහායක සම්බන්ධතා The contacts of a switching device, in addition to the main current contacts, that operate with the movement of the latter. They can be normally open (NO) or normally closed (NC) and change state when operated.
avalanche ඕඝය (ඇවලාන්ච්) A build up of particles caused by the collision of a high energy particle with any other form of matter. [Note: The term is derived from the avalanches occurring in a mountain]
average value සාමාන්‍ය අගය The average value of a periodic waveform is defined by taking the mean value of the full-wave rectified waveform.
avoided capacity cost වළක්වා ඇති ධාරිතා පිරිවැය Avoided capacity cost of constructing new power plants.
avoided cost වළක්වා ඇති පිරිවැය Cost that a utility avoids by purchasing power from an independent power producer(IPP), rather than generating power themselves, or constructing new power plants. A Public Utility calculates avoided costs for each utility, which are the basis upon which IPPs are paid for the electricity they produce. There are two parts to an avoided cost calculation: the avoided capacity cost and the avoided energy cost.
avoided energy cost වළක්වා ඇති බලශක්ති පිරිවැය Avoided energy cost of fuel and operating and maintaining utility power plants.
AWG, American Wire Gage ඇමරිකානු වයර් ගේජ් This term refers to the U.S. standard set of non-ferrous wire conductor sizes
axial ආක්ෂක In the same direction as the axis, parallel to the axis.
axis අක්ෂය Line about which a given body or system is considered to rotate.
axis of symmetry සමමිති අක්ෂය Line about which a given figure is symmetrical.
B මුලට TOP
back emf, back electromotive force විද්‍යුත් ප්‍රතිගාමක බලය The emf set up in the coil of an electric motor, opposing the current flowing through the coil, when the armature rotates.
back flashover ආපසු පිටිසැණෙළීම Flash-over occurring from an object usually at earth potential (such as a tower) to a line conductor due to the potential of the earthed object rising due to lightning.
bad conductor කුසන්නායකය A substance or element that will not easily conduct heat or electricity (or both) as easily as a conductor.
bad electrical contact විද්‍යුත් දුස්ස්පර්ශය Poor electrical contact across a joint can cause circuit resistance to increase and the joint to heat up and cause poor performance in a wide variety of electrical devices.
balanced three phase සමතුලිත තෙකලා (ත්‍රිකලා) A three phase voltage or current is said to be balanced when the magnitude of each phase is the same, and the phase angles of the three phases differ from each other by 120o. A star-connected load or a delta-connected load is said to be balanced when the three arms of the star or the delta have equal impedances in magnitude and phase.
ballast තුලබරුව A Ballast is an electrical device which is required for all discharge lamps. It limits the current through the lamp, preventing damage to both the lamp and the electrical supply.
ballistic galvanometer ප්‍රාක්ෂේප ගැල්වනොමීටරය Instrument for measuring the total quantity of electricity passing through a circuit due to a momentary current. The period of oscillation of the galvanometer must be long compared with the time during which the current flows.
ballistics ප්‍රාක්ෂේප විද්‍යාව The study of the flight path of projectiles.
bandpass filter කලාප තරණ පෙරහන A filter designed to pass all frequencies within a band of frequencies.
bandstop filter කලාප නැවැත්ම පෙරහන A filter designed to eliminate all frequencies within a band of frequencies.
bandwidth කලාප පළල Commonly defined as the difference between the upper and lower frequencies of the half power points of the response relative to the reference frequency. The data a cable can carry measured in bits per second (bps).
bar බාරය Unit of pressure equivalent to 105 pa.
barometer බැරෝමීටරය (වායු පීඩනමානය) Instrument for measuring atmospheric pressure.
barrier බාධකය A part providing a defined degree of protection against contact with live parts from any usual direction of access.
base පාදම The part of a transistor which separates the emitter from the collector. The middle part of the transistor. permits electrons from emitter to pass through to the collector.
base පදනම The reference quantity in a per-unit or percentage calculation.
base load (මූලික භාරය), අවම ජවය The minimum load experienced by an electric utility system over a given period of time, which must be supplied at all times.
base load capacity (මූලික පැටවීම් ධාරිතාව), අවම ජව ධාරිතාව Capacity of generating equipment operated to serve loads 24-hours per day.
base load plant (මූලික පැටවුම් බලාගාරය), අවම ජව උත්පාධිත බලාගාරය A power plant built to operate around-the-clock. Such plants tend to have low operating costs and high capital costs and are best utilized by running continuously. Coal fired and nuclear fuelled plants are typical base load plants.
baseline forecast මූලික පුරෝකථනය (අනාවැකිය) A prediction of future energy needs which does not take into account the likely effects of new conservation programs that have not yet been started.
basic insulation මූලික පරිවරණය Insulation applied to live parts to provide basic protection against electric shock and other hazards, which do not necessarily include insulation used exclusively for functional purposes.
basic insulation level, BIL මූලික පරිවාරක මට්ටම It defines the insulation level of power system equipment. It is a statement of the impulse (lightning or switching as appropriate) withstand voltage and the short duration power frequency withstand voltage.
battery බැටරිය A number of primary or secondary cells arranged in series or parallel. A device for turning chemical energy into electrical energy.
battery backup බැටරි උපස්ථය A battery or a set of batteries in a UPS system. Its purpose is to provide an alternate source of power if the main source is interrupted.
battery charger බැටරි ආරෝපකය​(චාලකය) A device or a system which provides the electrical power needed to keep the battery backup fully charged.
BCD, binary coded decimal ද්විමය කේතගත දශම A numeric code based on 0 and 1 in which each digit of a decimal number is represented individually by its binary equivalent.
Beckmann thermometer බෙක්මන් උෂ්ණත්වමානය Sensitive thermometer for measuring small differences or changes in temperature.
bel බෙල Ten decibels. (see decibel) ශබ්දය මනින සාපේක්ෂක ඒකකයක් bel expresses the logarithmic ratio between two levels of signal power, voltage, or current.
Bewley lattice diagram බෙව්ලි දැලිස් රූප සටහන This is a convenient diagram devised by Bewley, which shows at a glance the position and direction of motion of every incident, reflected, and transmitted surge on the system at every instant of time. The diagram overcomes the difficulty of otherwise keeping track of the multiplicity of successive reflections at the various junctions.
B-H Loop BH පුඩු Loop shows the relationship between the magnetic flux density (B) and the magnetizing force (H). It is also referred to as the hysteresis loop.
BIL, basic insulation level මූලික පරිවාරක මට්ටම It defines the insulation level of power system equipment. It is a statement of the impulse (lightning or switching as appropriate) withstand voltage and the short duration power frequency withstand voltage.
bilateral contract ද්විපාර්ශ්වික ගිවිසුම A direct contract between the power producer and user or broker outside of a centralized power pool.
billion බිලියන A thousand million or 109 (US). Also a million million (British)
bimetallic strip ද්විලෝහක තීරුව A strip composed of two different metals welded together in such a way that a rise of temperature will cause it to deform as a result of the unequal expansion. It is used in switches for control of temperature.
binary cell ද්විමය කෝෂ An element in a computer which can store information by virtue of its ability to remain stable in one of two possible states.
binary coded decimal, BCD ද්විමය කේතගත දශම A numeric code based on 0 and 1 in which each digit of a decimal number is represented individually by its binary equivalent.
binary notation ද්විමය අංකනය A system of numbers which has only two different integer values 0 and 1.
biomass ජෛව ස්කන්ධය Any plant-derived organic matter available on a renewable basis, including dedicated energy crops and trees, agricultural food and feed crops, agricultural crop wastes and residues, wood wastes and residues, aquatic plants, animal wastes, municipal wastes, and other waste materials.
bipolar transistor ද්විධ්‍රැව ට්‍රාන්සිස්ටරය A transistor where both free electrons and holes are necessary for normal operation.
bisection සමච්ඡේදනය Division into two equal parts.
bit බිට් The unit of information in information theory. The amount of information required to specify one of two alternatives 0 and 1.
bitumen බිටුමන් A term covering numerous "tarry" mixtures of hydrocarbons.
black body කෘෂ්ණ වස්තුව Thermal radiator that absorbs completely all incident radiation, whatever the wavelength, the direction of incidence or the polarization.
blackout මුර්ඡා වීම (සම්පූර්ණ අඳුරු වීම) A total loss of the commercial electrical power lasting for more than one cycle. Blackouts can result from any of a number of problems, ranging from Acts of God (high winds, storms, lightning, falling trees, floods, etc.) to situations such as cables being cut during excavation, equipment failures at the utility, vandalism, corrosion, etc. Used synonymously with Outage. A power loss affecting many electricity consumers over a large geographical area for a significant period of time.
blanking හිස් කිරීම A process of making the trace, or parts of a trace, invisible.
bleaching විරංජනය Removing the colour from coloured materials by chemical transformation.
board of trade unit, BOT unit වාණිජ මණ්ඩල ඒකකය Unit of electrical energy (British) supplied to the consumer. Equal to 1 kWh. Energy obtained when a power of 1 kW of power is maintained for 1 hour.
Bode plot බෝඩි සටහන Semi-log plots of the magnitude (in decibel) and phase angle of a transfer function (or performance) against frequency.
boiling උතුරන The state of a liquid at its boiling point when the maximum vapour pressure of the liquid is equal to the external pressure to which the liquid is subject, and the liquid is freely converted into vapour.
boiling point තාපාංකය The temperature at which the maximum vapour pressure of the liquid is equal to the external pressure. The temperature at which the liquid boils freely under that pressure.
boiling water reactor, BWR උතුරන ජල ප්‍රතික්‍රියාකාරකය A nuclear reactor in which water is used as coolant and moderator. Steam is thus produced in the reactor under pressure and can be used to drive a turbine.
bonding බන්ධනය A complete and permanent electrical connection. The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and the capacity to conduct safely any current likely to be imposed.
bonding conductor බන්ධන සන්නායකය A protective conductor providing equipotential bonding.
boolean algebra බූලියන් වීජ ගණිතය, ද්වීමය වීජ ගණිතය A branch of symbolic logic used in computers. Logical operations are performed by operators such as "and", "or", in a way analogous to mathematical signs.
brake horse power, bhp, BHP තිරිංග අශ්ව බලය, රෝධක අහ්ව ජවය Horse power of an engine measured by the degree of resistance offered by a brake. Represents the useful power that the machine can develop.
branch අත්ත An element in a circuit connecting two nodes.
breakdown බිඳවැටීම The occurrence of a large current between electrodes separated by a dielectric at a critical voltage.
breaker කඩනය (බ්‍රේකර්) Short for circuit breaker.
breeder reactor අභිජනන ප්‍රතික්‍රියාකාරකය A nuclear reactor which produces the same kind of fissile material as it burns. For example, a reactor using plutonium as a fuel can produce more plutonium than it uses by conversion of Uranium-238.
bridge rectifier සේතු උදුකුරුව A full-wave rectifier where the diodes are connected in a bridge circuit (two of them are always conducting at any given time). This allows the current to the load during both the positive and negative alternation of the supply voltage. This is the most common type of rectifier circuit to produce a unidirectional voltage for an alternating input.
brightness දීප්තිය Brightness is the quotient of the luminous intensity of a small element of the source and the area of the element projected on to a plane perpendicular to the given direction. [Unit: candela per unit area or Cd/m2]
british thermal unit, BTU බ්‍රිතාන්‍ය තාප ඒකකය Quantity of heat required to raise the temperature of 1 pound of water through 1 oF. It is equal to 1054 joule or 251.98 calories.
broadband communications පුළුල් කලාප සන්නිවේදනය The result of utilities forming partnerships to offer consumers "one-stop-shopping " for energy-related and high-tech telecommunications services.
broker තැරැව්කරු A retail agent who buys and sells power. The agent may also aggregate consumers and arrange for transmission and other ancillary services as needed.
brownout අඳුරු වීම (බ්‍රවුන්අවුට්) A long duration reduction in the voltage of the ac supply without complete loss of power. Brownouts are usually caused by heavy usage during peak hours and sometimes may even be planned as an energy conservation strategy.
brownout අඳුරු කිරීම A controlled power reduction in which the utility decreases the voltage on the power lines, so consumers receive lower quality electricity. Brownouts can be used if total power demand exceeds the maximum available supply.
building service entry ගොඩනැගිලි සේවා ප්‍රවේශය The point where commercial power enters the building.
bulk power market තොග බලශක්ති වෙළඳපොල Wholesale purchases and sales of electricity.
bulk power supply තොග බල සැපයුම Commonly used interchangeably with wholesale power supply. In broader terms, it refers to the aggregate of electric generating plants, transmission lines, and related equipment.
burning පිළිස්සීම combustion - A chemical reaction or complex chemical reaction, in which a substance combines with oxygen producing heat, light and flame.
busbar බස් තීරුව (නිය දඩුව) A rigid conductor used for connecting together distributors or feeders.
busbar නිය දඬුව A busbar, or bus bar, is a metallic strip or bar, typically housed inside switchgear and panel boards, for local power distribution.
bushing බුෂිං Bushings are insulators which are used to take high voltage conductors through earthed barriers such as walls, floors, metal, and tanks.
Butterworth filter බටර්වර්ත් පෙරනය (ෆිල්ටරය) A filter designed to produce a flat response up to the cut-off frequency.
bypass capacitor විපථ ධාරිත්‍රකය A capacitor placed from a dc signal to ground to remove any ac component of the signal by creating an ac short circuit to ground.
byte ද්වයාංක සංඛ්‍යාව Abbreviation for binary term, a unit of storage capable of holding a single character. A group of usually 8 bits in almost all modern computers.
C මුලට TOP
cable කේබලය, (විදුලි රැහැන) Conducting wire or wires separated and surrounded by a dielectric substance or insulation.
cable channel කේබල් නාලිය An enclosure situated above or in the ground, ventilated or closed, and having dimensions which do not permit the access of persons but allow access to the conduits and/or cables throughout their length during and after installation. A cable channel may or may not form part of the building construction.
cable coupler කේබල් කප්ලර්, කේබල් ඈඳනය A means of enabling the connection or disconnection, at will, of two flexible cables. It consists of a connector and a plug.
cable ducting කේබල් ප්‍රනාලිය An enclosure of metal or insulating material, other than conduit or cable trunking, intended for the protection of cables which are drawn in after erection of the ducting.
cable ladder කේබල් ඉණිමඟ A cable support consisting of a series of transverse supporting elements rigidly fixed to main longitudinal supporting members.
cable tray කේබල් තැටි A rigid structure use to support cables. A raceway consisting of a continuous base with raised edges and no covering. A cable tray may or may not be perforated.
cable trunking කේබල් මාමැඟැයීම A closed enclosure normally of rectangular cross section, of which one side is removable or hinged, used for the protection of cables and for the accommodation of other electrical equipment.
cable tunnel කේබල් උමග A corridor containing supporting structures for cables and joints and/or other elements of wiring systems and whose dimensions allow persons to pass freely throughout the entire length.
calibration ක්‍රමාංකනය The graduation or confirmation of the graduation of an instrument to enable measurements in definite units to be made with it. Thus for example the deflection of a meter can be calibrated to read the current causing the deflection.
calorie (cal) කැලරි Unit of quantity of heat. The amount of heat required to raise the temperature of 1 gram of water through 1oC. 1 calorie = 4.184 joule.
calorific value තාපජනක අගය The calorific value of a fuel is the quantity of heat produced by a given weight of the fuel on complete combustion.
candela (Cd) කැන්ඩෙලා The candela is the SI unit of luminous intensity. It is defined as the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian [1979]
candle power ඉටිපන්දම් බලය The candle power of a light source, in a given direction, is the luminous intensity of the source in that direction expressed in terms of the candela.
capability හැකියාව Maximum load that a generating unit can carry without exceeding ratings.
capacitance ධාරණාව The ability of a system of electrical conductors and insulators to store electric charge when a potential difference exists between the conductors. It is expressed as a ratio of the electrical charge stored to the voltage across the conductors. [Unit: farad or F]
capacitor ධාරිත්‍රකය A device consisting of two conducting surfaces separated by a layer of insulating material (dielectric)and having the ability of storing electric energy. Also called a condenser, the principal characteristics of which is the capacitance.
capacitor voltage transformer, CVT ධාරිත්‍රක වෝල්ටීයතා ට්‍රාන්ස්ෆෝමරය A CVT is a transformer used in power systems to step down extra high voltage signals and provide a low voltage signal, for metering or operating a protective relay.
capacity ධාරිතාව The maximum load a generating unit, generating station, or other electrical apparatus is rated to carry by the manufacturer or can actually carry under existing service conditions.
capacity charge ධාරිතා ගාස්තුව An charge or assessment based on the amount of capacity being purchased.
capacity factor ධාරිතා සාධකය The ratio of the electric energy produced by a generating unit to the electrical energy that could have been produced at continuous full-power operations.
captive consumer බන්ධනයට අසුවූ පාරිභෝගිකයා A consumer who does not have realistic alternatives to buying power from the local utility, even if that consumer had the legal right to buy from competitors.
captive generation උත්පාදක සමාගමේ පරිශ්‍රයේ ජනනය Generating plant available at CEB customer facilities, but not connected in parallel with the CEB network.
captive load උත්පාදක සමාගම් පරිශ්‍රය තුළ පැටවීම් Load which may be supplied by an Embedded Generator, in addition to the generator auxiliaries, which is within the Generating Company premises.
carnot's cycle කානෝ තාප​ චක්‍රය An ideal reversible four step cycle of operations for the working substance of a heat engine.
carrier වාහකය In a semiconductor, the mobile electrons or holes which carry charges are called carriers.
carrier wave වාහක තරංගය A continuous electromagnetic radiation, of constant amplitude and frequency, emitted by a transmitter. By modulation of the carrier wave, oscillations caused at the transmitting end are conveyed to the receiving end.
cartesian coordinates, cartesian co-ordinates කාටිසීය ඛණ්ඩාංක A system where the location of a point is given by coordinates that represent its distances from perpendicular axes that intersect at a point called the origin - in 2-dimentional space x-axis, y-axis and in 3-dimentional space x-axis, y-axis, z-axis.
cartridge fuse පතරොම් විලායකය (කාට්රිජ් ෆියුස් ) It is a fuse inside a cartridge. The fuse wire is usually enclosed in an evacuated glass tube with metal end caps.
cartridge fuse link කාට්රිජ් ෆියුස් සබැඳිය A device comprising a fuse element or several fuse elements connected in parallel enclosed in a cartridge usually filled with arc extinguishing medium and connected to terminations (see fuse link).
cascade connection කඳුරැලි සම්බන්ධනය An arrangement of two or more components or circuits such that the output of one is the input to the next.
catenary දාමවක්‍ර වක්‍රය Curve formed by a chain or string hanging from two fixed points.
cathode කැතෝඩය Negative electrode. The element of an electronic device that provides the flow of electrons.
cathode ray oscilloscope, CRO කැතෝඩ කිරණ දෝලනේක්ෂය An instrument based upon the cathode ray tube, which provides a visible image of one or more rapidly varying electrical quantities.
cathode ray tube, CRT කැතෝඩ කිරණ තලය An electron-beam tube in which the beam can be focused to a small cross-section on a luminescent screen and varied in both position and intensity to produce a visible pattern. Electric potentials applied to the deflection plates are used to control the position of the beam, and its movement across the screen, in a desired manner.
celsius (oC) සෙල්සියස් Degrees celsius is an international thermometric scale on which the interval between the triple point of water and the boiling point of water is divided into 99.99 degrees with 0.01° representing the triple point and 100° the boiling point. Celsius degrees are the same size as kelvin but the zero point is shifted to the triple point of water, minus 0.01 K. (0 °C = 273.15 K). Note: The thermodynamic temperature of the triple point of water is 273.16 K
centi (c) සෙන්ටි (සියයෙන් පංගුවක්) Decimal sub-multiple prefix corresponding to one-hundredth or 10-2 . This is not a preferred suffix.
centigrade සෙන්ටිග්‍රේඩ් Older name for celsius.
central processing unit මධ්‍යම සැකසුම් ඒකකය CPU - the part of a computer in which operations are controlled and executed.
centre of gravity ගුරුත්ව කේන්ද්‍රය, ගුරුත්වාකර්ෂණ කේන්ද්‍රය The centre of gravity of a body is the fixed point through which the resultant force due to the Earth's attraction upon it always passes, irrespective of the position of the body.
centrifugal force කේන්ද්‍රාපසාරී බලය The outward force acting on a body rotating in a circle round a central point.
centripetal force කේන්ද්‍රාභිසාරී බලය The radial force imposed by the restraining system, necessary to keep the body moving in a circular path. [Note: the centrifugal force and the centripetal force are equal and opposite].
ceramic පිඟන් මැටි pertaining to products involving the use of clay or other silicates.
ceylon electricity board, CEB ලංකා විදුලිබල මණ්ඩලය A body corporte duly constituted by Act No. 17 of 1969 of the Democratic Socialist Republic of Sri Lanka.
CFL සංයුක්ත ප්‍රතිදීපන පහන [see compact fluorescent lamp]
cgs system, centimetre-gram-second system සෙන්ටිමීටර ග්‍රෑම් තත්පර ක්‍රමය A decimal system which is an earlier form of the metric system.
chain reaction දාම ප්‍රතික්‍රියාව Any self-sustaining molecular or nuclear reaction, the products of which contribute to the propagation of the reaction.
channel රූපවාහිනී නාලිකාව In television, a portion of the RF spectrum 6 MHz wide which carries the audio and video carriers of the television signal.
characteristic ලාක්ෂණික A feature or quality belonging typically to an equipment or thing, and serving to identify them.
characteristic impedance ලාක්ෂණික සම්බාධනය Is the particular value of the load impedance which produces an input impedance with the value as that of the load impedance. For a transmission line, it is the input impedance of an infinitely long transmission line.
charge ආරෝපණය electric charge
chemical reaction රසායනික ප්‍රතික්‍රියාව The interaction of two or more substances resulting in chemical changes in them.
chip චිපය The finished IC (integrated circuit) is commonly known as a chip.
choke අනුබාධනය (චෝක්) A coil of low resistance and high inductance used in electrical circuits to pass low frequency or direct components while suppressing (or choking) the higher frequency undesirable alternating currents.
chop mode චොප් ප්‍රකාරය A vertical mode of operation for dual-trace oscilloscopes in which the display is switched between the two channels at some fixed rate much less than the sweep time.
chopped waveform ලොප් කළ තරංග ආකෘතිය The standard surge waveform applied is suddenly made zero (chopped) at a predefined time to simulate the surge waveform with flashover.
circuit පරිපථය An electrical circuit is the complete path traversed by an electric current. An assembly of electrical equipment supplied from the same origin and protected against overcurrent by the same protective device(s).
circuit breaker පරිපථ බිඳිනය A mechanical switching device capable of making, carrying, and breaking currents under normal conditions. Also making, carrying for a specific time, and automatically breaking currents under specified abnormal circuit conditions, such as those of short circuit. It is usually required to operate infrequently although some types are suitable for frequent operation.
circuit protective conductor, cpc පරිපථ ආරක්ෂිත සන්නායකය, පරිපථ ආරක්‍ෂන​ සන්නායකය A protective conductor connecting exposed conductive parts of equipment to the main earthing terminal.
circular mil කව මිල A unit of area used in measuring the cross section of fine wire. 1 circular mil corresponds to the area of a circle whose diameter is equal to one-thousandth of an inch. 1 circular mil = 0.5067*10-9 m2
circularly polarised light වෘත්ත ලෙස ධ‍්‍රැවිත ආලෝකය Light which can be resolved into two vibrations lying in planes at right angles, of equal amplitude and frequency and differing in phase by 90o.
circumference පරිධිය The enclosing boundary of a curved geometric figure, especially a circle.
clamp කලම්පය, කලම්ප ගසනවා A device, usually rigid, for fastening objects together.
clamping circuit කලම්ප පරිපථය An electric circuit which serves to maintain the limits of a signal at prescribed levels.
clamping level කලම්ප මට්ටම The voltage point at which a surge protector begins to limit surges.
class I equipment 1 පන්තියේ උපකරණ Equipment in which protection against electric shock does not rely on basic insulation only, but which includes an additional safety precaution in that means are provided for the connection of the equipment to the protective earth conductor in the fixed wiring of the installation in such a way that accessible metal parts cannot become live in the event of a failure of basic insulation.
class II equipment 2 පන්තියේ උපකරණ Has supplementary insulation and therefore does not rely on an earth for protection and is easily identified by the double square symbol and will receive an insulation test.
class III equipment 3 පන්තියේ උපකරණ Equipment in which protection against electric shock relies on supply at SELV and in which voltages higher than those of SELV are not generated.
clean power පිරිසිදු ජවය Electrical power which has been conditioned and/or regulated to remove electrical noise from the output power.
clearance වාසිය The amount of clear space between two objects. Fo example, the minimum distance between bottom conductor of a transmission line and the earth.
clipping circuit ඉමැයුම් පරිපථය A circuit designed to prevent a voltage from exceeding a predetermined reference level.
clock ඔරලෝසුව The basic timing signal in a digital system.
CMOS අනුපූරක ලෝහ ඔක්සයිඩ් අර්ධ සන්නායක A circuit with complementary MOS (Metal Oxide Semiconductor) transistors.
coal ගල් අඟුරු A material occurring in large underground deposits consisting of carbon and various carbon compounds. Formed by the decomposition of vegetable matter over many millions of years.
coaxial cable, co-axial cable සමාක්ෂක කේබලය A transmission medium usually consisting of one central wire surrounded by an insulator and encased in either a wire mesh or an extruded metal sheathing. Consists of a cylinder of electrically conducting material surrounding a central conductor held in place by insulation.
code කේතය A set of instructions forming a program which is executed by a computer or similar device.
coefficient සංගුණකය A number or other known factor or multiplier which measures some specified property of a given substance or algebraic expression. A numerical quantity multiplying the variable in an expression.
coercive force, coercivity අපහාරක බලය, අපහාරකතාව The magnetic force, equivalent to the field intensity. necessary to demagnetize an already magnetized material.
cogeneration සමජාතීයකරණය The production of electricity and the utilization of waste heat, which could be used to produce steam for additional power generation (as in a combined cycle facility).
coil දඟරය one or more turns of current-carrying wire designed to produce a magnetic field or to provide electrical inductance.
coincidence සම්පාතය A concurrence of events without an apparent causal connection.
coincidence factor අහම්බෙන් සිදුවීම සාධකය The ratio of the coincident maximum demand of two or more loads to the sum of their non-coincident maximum demands for a given period.  The coincidence factor is the reciprocal of the diversity factor and is always less than or equal to one.
coincidental demand සමපාතීය ඉල්ලුම Two or more demands that occur at the same time.
coincidental peak load සමපාතීය උපරිම පැටවීම Two or more peak loads that occur at the same time.
collector සංග්‍රාහකය The electrode in a transistor through which a primary flow of carriers leaves the inter-electrode region. It is called a collected because it collects or gathers the carriers sent into the base by the emitter.
collision සංඝට්ටනය An event in which two or more objecs exert forces on each other in about a relatively short time, usually with great force.
colour වර්ණය The sensation of colour is the result of the interpretation by the human central nervous system of the effect produced upon the eye by electromagnetic radiation of a particular wave length.
colour coordinates වර්ණ ඛණ්ඩාංක A set of coordinates representing the position of a color in a color space. For example, an RGB color space is any additive color space based on the red-green-blue color model.
colour rendering වර්ණ විදැහුම්කරණය General expression for the effect of an illuminant on the color appearance of objects in conscious or subconscious comparison with their color appearance under a reference illuminant.
colour temperature වර්ණ ලප උෂ්ණත්වය A measureme of the temperature of a black-body radiator which would emit radiation of the same chromaticity as the light under consideration. The higher the colour temperature, the bluer it is, and the lower the colour temperature, the redder it is. [Unit kelvin, K]
combined cycle ඒකාබද්ධ චක්‍රය Combines the gas turbine cycle together with a heat recovery steam cycle that extracts heat from the gas turbine exhaust flow to produce steam.
combined cycle unit ඒකාබද්ධ චක්‍රීය ඒකකය An electricity generating unit consisting of one or more gas (combustion) turbines combined with a steam turbine. The steam turbine utilises the waste exhaust heat from the combustion turbines. This process increases the efficiency of the electric generating unit.
combined heat and power, CHP ඒකාබද්ධ තාපය හා ජවය A plant that generates electricity and supplies thermal energy, typically steam, to an industrial or other heating requirement.
combustion or burning දහනය හෝ පිළිස්සීම A chemical reaction or complex chemical reaction, in which a substance combines with oxygen producing heat, light and flame.
combustion turbine දහන ටර්බයිනය A type of generating unit normally fired by oil or natural gas. The combustion of the fuel produces expanding gases, which are forced through a turbine, thereby generating electricity.
commercial operation වාණිජ ක්‍රියාකාරිත්වය Commercial operation occurs when control of the generator is turned over to the system dispatcher.
common mode noise පොදු මාදිලියේ ශබ්දය Electrical noise or interference between each of the conductors and ground
common mode signal පොදු මාදිලියේ සංඥාව A signal that is applied with equal strength to both inputs of a differential amplifier or an operational amplifier.
common mode tripping පොදු මාදිලිය කැපීම Automatic removal of two or more generating plant from the system owing to a cause that is common to both or all the generators.
communication සන්නිවේදනය Process of sending or receiving information.
commutation න්‍යාදේශ The transfer of current from one path to another.
commutation angle, overlap angle සංක්‍රමණ කෝණය, අතිච්ඡාදනය කෝණය The commutation period between two thyristors on the same side of the bridge is the angle by which one thyristor commutates to the next.
commutator න්‍යාදේශකය, කොමියුටේටරය A device for reversing the direction of flow of electric current in a machine.
compact fluorescent lamp, CFL සංයුක්ත ප්‍රතිදීප්ත පහන A fluorescent lamp in compact form that may be conveniently used, in normal holders, in place of the lesser efficient incandescent lamps. The lamp life is significantly longer than incandescent lamps.
comparator සංසන්දකය, සසඳුව A device to compare a measurable quantity with a reference.
compass මාලිමාය The magnetic compass is used to obtain the direction of the earth's magnetic field at a point. In its simplest form consists of a magnetised needle pivoted at its centre so that it is free to move in a horizontal plane.
competitive bidding තරඟකාරී ලංසු තැබීම This is a procedure that utilities use to select suppliers of new electric capacity and energy. Under competitive bidding, an electric utility solicits bids from prospective power generators to meet current or future power demands. Competitive bidding systems to select more fairly among numerous supply alternatives.
complementary අනුපූරකතාව Combining to enhance or emphasize the qualities of another.
complex conjugate සංකීර්ණ ප්‍රතිබද්ධය A complex number having the identical real part and the negative of the imaginary part of the original complex number.
complex number සංකීර්ණ සංඛ්‍යාව Consists of two parts, real and imaginary. They obey the ordinary laws of algebra except that their real and imaginary parts must be equated separately.
complementary MOS, CMOS අනුපූරක ලෝහ ඔක්සයිඩ් අර්ධ සන්නායක A method of reducing the current drain of a digital circuit by combining n-channel and p-channel MOSFETs.
component සංරචකය A constituent element or part of an electrical system.
composite සංයුත Composite materials are made when two or more materials with different properties are combined to produce a new material. The physical and chemical properties of each of the constituent materials remain distinct in the new material.
compound motor සංයුක්ත මෝටරය A d.c. motor with both a series connected winding as well as a shunt connected winding. Depending on whether the fields of the series winding and the shunt winding aid each other or oppose each other, they are called cumulative compound or differential compound
computer පරිගණකය A machine (now electronic device) that processes sequences of arithmetic or logical operations automatically according to a set of given instructions in a program, storing data, typically in binary form.
concentric ඒකකේන්ද්‍රීය වෘත්ත Circles or things having the same centre.
condenser කන්ඩෙන්සර් Capacitor
condition monitoring තත්ව අධීක්ෂණය The process of monitoring a parameter of condition in machinery (leakage current, temperature etc.), in order to identify a significant change, indicative of a developing fault. It is a major component of predictive maintenance.
conductance සන්නයනතාව The conductance is the reciprocal of the resistance in a resistive circuit, or the real part of the admittance in a complex circuit. It is also the ability of an element to conduct electric current [Unit: siemens or S]
conductivity සන්නායකතාව Electrical conductivity is the reciprocal of electrical resistivity.
conductor සන්නායකය A wire, cable, rod, tube or bus bar designed for the passage of electrical current. An object or substance which conducts electric current.
conductor loss සන්නායක හානිය​(සන්නායක ප්‍රතිරෝධ නිසා සිදුවන ජව අපතේ යාම​) Loss occurring in a conductor due to the flow of current. Also known as the I2 R loss and copper loss.
conduit වාහකය A tubular raceway for power or data cables. Both metallic conduit and non-metallic forms may be used.
connector සම්බන්ධකය The part of a cable coupler or of an appliance coupler which is provided with female contacts and is intended to be attached to the end of the flexible cable remote from the supply.
conservation සංරක්ෂණ Reducing energy consumption and energy waste using a strategy to attain higher efficiency in energy production and utilization, to accommodate behaviour to maximize personal welfare in response to changing prices, and shifting from scarce to more plentiful energy resources.
conservation of angular momentum කෝණික ගම්‍යතා සංස්ථිතිය A physical property of a spinning system such that its spin remains constant unless it is acted upon by an external torque.
conservation of charge ආරෝපණ සංස්ථිතිය The law of conservation of charge states that the total electric charge in an isolated system does not change.
conservation of energy ශක්ති සංස්ථිතිය, බලශක්ති සංරක්ෂණය The law of conservation of energy states that in any system energy cannot be created or destroyed.
conservation of mass ස්කන්ධය සංස්ථිතිය (ස්කන්ධය සංරක්ෂණය) The law of conservation of mass states that in any system matter cannot be created or destroyed.
conservation of mass and energy ස්කන්ධය හා ශක්තිය සංස්ථිතිය (ස්කන්ධය හා ශක්තිය සංරක්ෂණය කිරීම) A principle resulting from Einstein's special theory of relativity, which combines the separate laws of conservation of mass and energy. It states that in any system the sum of the mass and energy remains constant.
conservation of momentum ගම්‍යතා සංස්ථීතිය, ගම්‍යතාව සංරක්ෂණය The law of conservation of momentum states that for a perfectly elastic collision, the total momentum of two bodies before impact is equal to their total momentum of two bodies before impact is equal to their total momentum after impact.
constrained සංරුද්ධ Something that imposes a limit or restriction while accomplishing a goal.
consumer පාරිභෝගික A person or organisation that purchases a product, usually electricity.
consumer education පාරිභෝගික අධ්‍යාපනය Efforts to provide consumers with skills and knowledge to use their resources wisely in the marketplace
consumer service charge පාරිභෝගික සේවා ගාස්තු Portion of the consumer's bill which remains the same from month to month. The charge is determined separately from the amount of energy used based on the costs associated with connecting a consumer to the utility's distribution system, including the service connection and metering equipment. This charge also recovers expenses such as meter reading, billing costs, consumer accounting expenses records and collections, and a portion of general plant items such as office space for consumer service personnel.
consumer unit පාරිභෝගික ඒකකය (may also be known as a consumer control unit or electricity control unit) A particular type of distribution board comprising a co-ordinated assembly for the control and distribution of electrical energy, principally in domestic premises, incorporating manual means of double pole isolation on the incoming circuit(s) and an assembly of one or more fuses, circuit breakers, residual current operated devices or signalling and other devices purposely manufactured for such use.
contactor ස්පර්ශත්‍රිය An electro-mechanical device that is operated by an electric coil and allows automatic or remote operation to repeatedly establish or interrupt an electrical power circuit. A contactor provides no overload protection as required for motor loads.
contamination දූෂණය, අපවිත්‍රනය Contamination is the unwanted pollution of something by another substance.
continuity අඛණ්ඩතාව Continuous, without a break.
contract price ගිවිසුම් මිල Price marketed on a contract basis for one or more years.
convection සංවහනය Transference of heat through a liquid or gas by the actual movement of the fluid.
convection සංවහනය The movement within a fluid caused by the hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
converter පරිවර්තකය A device which changes electrical energy from one form to another, such as from alternating current to direct current.
convolution සංචලිතය The convolution of two signals consists of time-reversing one of the signals, shifting it, and multiplying it point by point with the second signal,and integrating the product. It is used to characterise physical systems.
cooperative electric utility සමුපකාර විදුලි උපයෝගීතාව A utility established to be owned by and operated for the benefit of those using its services.
co-ordinated සම්බන්ධීකරණය Usually refers to characteristics which are co-ordinated to give optimum performance.
coordinates ඛණ්ඩාංක Distances or angles, that uniquely identify points in 2D) or 3D space.
copper loss තඹ වල ජව හානිය තඹ වල ජව හානිය
core මධ්‍යය, හර A piece of magnetic material with a high magnetic permeability used to confine and guide magnetic fields in electrical, electromechanical and magnetic devices.
core assembly හර එකලස Process of assembly of the laminations of a transformer core.
core loss චුම්බක හර හානිය The Loss occurring in a magnetic core due to alternating magnetisation. It is the sum of the hysteresis loss and the eddy current loss.
corona රස් වළල්ල (කොරෝනා) A glowing circle of light around an object. A luminous discharge which appears surrounding a conductor surface without sparking or flash over.
corona discharge රැස් වළලු විසර්ජනය (කොරෝනා විසර්ජනය) Bluish white luminous discharge which appears surrounding a conductor surface at a field exceeding corona inception, but not being sufficient to cause sparking or flash over.
corona inception රැස් වළලු ආරම්භය Inception of the ionisation of the air on the surface of a conductor, caused by the voltage gradient exceeding a critical value, but not being sufficient to cause sparking or flash over.
corona loss රැස් වළලු හානිය power loss due to corona.
correlation සහසම්බන්ධය A mutual relationship or connection between two or more things or signals.
corrosion විඛාදනය Surface chemical action, especially on metals, by the action of moisture, air or chemicals.
co-tree of network ජාලයේ සම-ගස Complement of the tree of the network.
coulomb (C) කූලෝම් SI unit of electric charge. One coulomb is equal to the amount of charge accumulated in one second by a current of one ampere.
coulomb's law කූලෝම්ගේ නියමය The force of attraction or repulsion between two point charges is proportional to the magnitude of the charges and inversely proportional to the square of the distance between them.
coupling ඈඳුම A device used to connect two shafts together at their ends for the purpose of transmitting power. It can also be a power transfer process during which the current change of one circuit affects another circuit through their mutual inductance.
CPU මධ්‍යම සැකසුම් ඒකකය An acronym used for the central processing unit of a computer.
creep ඇඳී යාම Slow steady movement, especially when imperceptible.
creepage distance ක්‍රිපේජ් දුර Shortest path along the surface of insulating material between two conductive parts.
creeping discharge (on insulator) පරිවාරක වල බඩගා යන විසර්ජනය, පරිවාරකයේ මතුපිට විසර්ජනය A phenomenon in which discharge occurs along an insulating surface. This occurs as a result of a localized discharge.
crest and troughs ශීර්ෂ සහ නිම්න A crest is the point on a wave with the maximum upward value within a cycle, while a trough is the the minimum or lowest point in a cycle.
crest factor කුළු සාධකය The ratio of the peak or maximum value of a wave, to the r.m.s. value.
critical damping අවධි පරිමන්දනය Critical damping provides the quickest approach to final value in a damped oscillation. With underdamping it reaches the final position more quickly, but oscillates around it. With overdamping there is no oscillation but approaches final value more slowly.
critical earth volume අවධි පෘථිවි පරිමන්දනය Part of the earth surrounding an earth electrode that exercises the greatest influence on the earth electrode resistance.
critical mass අවධි ස්කන්ධය The minimum amount of fissile material required in a nuclear reactor to sustain a chain reaction.
CRO, Cathode Ray Oscilloscope කැතෝඩ කිරණ දෝලනේක්ෂය An instrument based upon the cathode ray tube, which provides a visible image of one or more rapidly varying electrical quantities.
cross section හරස්කඩ A shape exposed by making a straight cut through a body, especially at right angles to an axis.
cross-bonding හරස් බන්ධනය A method of connecting the sheaths of single core cables in a three phase system in order to reduce the circulating currents flowing in the sheaths.
cross-subsidization හරස් සහනාධාරය The transfer of assets or services from the regulated portion of an electric utility to its unregulated affiliates to produce an unfair competitive advantage.  Cross-subsidy can refer to one rate class (such as industrial consumers) subsidizing the rates of another class (such as residential consumers).
crow bar අලවංගුව A bar, usually metal, flattened and slightly bent at one end, used as a lever to help lift heavy objects off the ground.
CRT කැතෝඩ කිරණ නළය [ see cathode ray tube]
crystal ස්ඵටිකය A solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.
cumulo-nimbus cloud සමුච්චිත-නිම්බස් වලාකුළු Thunder cloud from which lightning strikes originate.
curie කියුරිය (විකිරණශ්‍රීලිතාව මනින ඒකකය) Measure of the activity of a radioactive substance. It is defined in terms of the rate of decay of a quantity of a radioactive isotope.
current ධාරාව electric current
current balance ධාරා තුලාව Instrument for the determination of an electric current in absolute electromagnetic units.
current carrying capacity (conductor) සන්නායකයක වත්මන් ප්‍රවාහ ධාරිතාව The maximum current which can be carried by a conductor under specified conditions without its steady state temperature exceeding a specified value.
current rating ධාරා වර්ගීකරණ This is the maximum current, which the fuse will carry for an indefinite period without undue deterioration of the fuse element.
current source ධාරා ප්‍රභවය A source which essentially maintains the source current at a predefined value almost independent of the load conditions.
current transformer, CT ධාරා පරිණාමකය An instrument transformer specifically designed to give an accurate current ratio for measurement and/or control purposes. They are always connected in series with the circuit (like an ammeter) and hence should never be allowed to have their secondary to be on open circuit to avoid saturation. A CT presents a negligible load to the primary circuit.
cut off කපා හැරීම A level which is designed to limit something, such as frequency.
cycle චක්‍රය One complete set of values through which an alternating voltage or current passes successively.
D මුලට TOP
daily peak දෛනික උපරිමය The maximum amount of power or energy or service demanded in one day from a company or utility service.
daily variation දෛනික විචලනය Fluctuations that occur between one day and the next.
damping පරිමන්දනය Decrease in the amplitude of an oscillation or wave motion with time.
danger අනතුර Risk of injury to persons (and livestock where expected to be present) from: (i) fire, electric shock and bums arising from the use of electrical energy, and (ii) mechanical movement of electrically controlled equipment, in. so far as such danger is intended to he prevented by electrical emergency switching or by electrical switching for mechanical maintenance, of non electrical parts of such equipment.
dart leader ශර නායකය A succeeding leader of a multiple-stroke flash lightning, occuring after the first lightning stroke. (The first stroke is initiated by a stepped leader.)
data දත්ත Information in numeric, alphanumeric, or other form.
data processing equipment දත්ත සැකසුම් උපකරණ Electrically operated machine units which, separately or assembled in systems, accumulate, process and store data. Acceptance and divulgence of data may or may not be by electronic means.
dc සරල ධාරාව (ස ධා) [see direct current]
dc network analysor ස ධා ජාල විශ්ලේෂකය The d.c. network analyser, comprising of variable power sources and variable resistances for the transmission lines is an early form of analog computer used in the study of the load flow problem. After an iterative solution it measured the network performance parameters of the equivalent ac network.
dc potentiometer සරල ධාරා විභවමානය A potentiometer in which the supply is a battery and the balance is under d.c. conditions.
decade දශකය A factor of 10.
decay ක්ෂය A gradual decline of a value, usually exponential. With exponential decay, the value decreases at a rate proportional to its current value.
deci (d) ඩෙසි (දහයෙන් එක් පංගුව) Decimal sub-multiple prefix corresponding to one-tenth or 10-1. This is not a preferred suffix.
decibel ඩෙසිබල් One tenth of a bel. A unit which compares levels of power in logarithmic form. Two power levels p1 and p2 are said to differ by n decibels given by n = 10 log10 p2/p1. In the case of sound, the intensity is often measured in decibel with reference to the lowest audible note of the same frequency.
decoupling වියෑදීම, වියෑඳුම To separate or disengage one thing from something else.
defibrillation අසාමාන්‍ය ලෙස වේගවත් හෘද රිද්මයන් නැවැත්වීමට විදුලි කම්පනය භාවිතා කිරීම (ඩීෆිබ්‍රිලේෂන්) The use of electric shock to stop abnormally fast heart rhythms. Electrical current is used to restore the heart's natural pacemaker function which resumes a normal heartbeat. The shock is administered through electrodes placed on the chest wall (external defibrillation) or in the heart (internal defibrillation).
defibrillator ඩීෆිබ්‍රිලේෂන් සඳහා විද්‍යුත් කම්පන ධාරාව නිපදවන උපකරණය The machine or device that produces the electric shock current for defibrillation
deflection උත්ක්‍රමය Movement of an indicating needle.
degree celsius (oC) සෙල්සියස් අංශක Degrees celsius is an international thermometric scale on which the interval between the triple point of water and the boiling point of water is divided into 99.99 degrees with 0.01° representing the triple point and 100° the boiling point. Celsius degrees are the same size as kelvin but the zero point is shifted to the triple point of water, minus 0.01 K. (0 °C = 273.15 K). Note: The thermodynamic temperature of the triple point of water is 273.16 K
deionisation ව්‍යයනීකරණය The process by which charged ions (both positive and negative) are removed from a liquid.
deka (da) ඩීකා Decimal multiple prefix corresponding to ten or 10. This is not a preferred suffix.
delay angle or control angle රමාද කෝණය හෝ පාලන කෝණය The control angle for rectification (also known as the ignition angle) is the angle by which firing is delayed beyond the natural take over for the next thyristor.
delay line පමා මඟ A cable or device producing a desired delay in the transmission of a signal.
delta connection ඩෙල්ටා සම්බන්ධතාවය A method of connecting three elements of a three-phase electrical system in a closed triangle or delta, and with the three phases being taken from the corners of the triangle.
demagnetisation විචුම්බකනය The process of removing the remnant magnetization from a material.
demand ඉල්ලුම The rate at which electric energy is delivered to or by a system, part of a system, or a piece of equipment. It is expressed in kilowatts, kilovoltamperes or other suitable unit at a given instant or averaged over any designated period of time. The primary source of "Demand" is the power-consuming equipment of the customers.
demand charge ඉල්ලුම් ගාස්තු The sum to be paid by a large electricity consumer for its peak usage level.
demand factor ඉල්ලුම් සාධකය The ratio of the maximum demand of a system, or part of a system, to the total connected load of a system or the part of the system under consideration.
demand-side management, DSM ඉල්ලුම පැත්තේ කළමනාකරණය The planning, implementation, and monitoring of utility activities designed to influence customer use of electricity in ways that will produce desired changes in a utility's load shape. Utility programs falling under the umbrella of DSM include: load management, customer generation, and innovative rates. These changes must produce benefits to both the utility and its customers.
demodulation විමූර්ඡන The process or separating information from a modulated carrier wave.
density ඝනත්වය The mass of unit volume of a substance. [Unit: kg/m3]. It can also specify the degree of compactness.
dependable capacity යැපුම් ධාරිතව​(විශ්වසනීය ධාරිතාව) The system's ability to carry the electric power for the time interval and period specified.  Dependable capacity is determined by such factors as capability, operating power factor and portion of the load the station is to supply.
depreciation, straight-line සරල රේඛීය ක්ෂයවීම Straight-line depreciation takes the cost of the asset less the estimated salvage value and allocates the cost in equal amounts over the asset's estimated useful life.
derating factor විවැගයීම සාධකය A value that tells how much to reduce the power rating of a device for each degree above the reference temperature.
deregulation පාලන රීති හා සීමා ඉවත් කිරීම The elimination of regulation from a previously regulated industry or sector of an industry.
derived units ව්‍යුත්පන්න ඒකක Units of physical measurement, other than the fundamental units, but derived from these.
design current (of a circuit) සැලසුම් ධාරාව (පරිපථයක) The magnitude of the current (rms value for a.c.) to be carried by the circuit in normal service.
designated agent නම් කරන ලද නියෝජිතයා An agent that acts on behalf of a transmission provider, consumer or transmission consumer as required under the tariff.
detection අනාවරණය The action or process of identifying or discovering the presence of something, usually concealed.
detector අනාවරකය A device for detecting the presence of something, such as a signal. An instrument to detect the unbalance in a bridge circuit.
deviation අපගමනය The amount by which a measurement differs from a fixed value such as the mean.
device උපාංගය A component of an electrical system that is intended to carry but not utilize electric energy. One that directly uses electrical energy to perform a specific task.
diac ඩයිඇක් A silicon bilateral device used to gate other devices such as triacs.
dielectric පාරවිද්‍යුත් Non-conductor of electricity. An insulator. Substance in which an electric field gives rise to no net flow of electric charge but only to a displacement of charge.
dielectric constant පාරවිද්‍යුත් නියතය Relative permittivity. It is the ratio of the capacitance of a capacitor with the given material as dielectric, to the capacitance of the same capacitor with vacuum (or air) as the dielectric.
dielectric heating පාරවිද්යුත් උණුසුම, පාරවිද්යුත් විද්‍යුත් තාපය A form of heating in which electrically insulating material is heated by being subjected to an alternating electric field. Results from energy being lost by the field to electrons within the atoms and molecules of the material.
dielectric loss පාරවිද්යුත් හානිය Loss occurring in the leakage resistance of the dielectric.
dielectric strength පාරවිද්යුත් ශක්තිය The ability of a dielectric material of specified thickness to withstand high voltages without breaking down.
diesel oil ඩීසල් තෙල් The oil left after petrol and kerosene have been distilled from crude petroleum. Used as a fuel in diesel engines.
difference amplifier වෙනස වර්ධකය A device that amplifies the difference between two inputs. It rejects any signals common to the two input.
differentiator අවකලකය An op amp whose output is proportional to the rate of change of the input signal.
diffuse reflection විසරණය පරාවර්තනය Diffusion by reflection in which, on the macroscopic scale, there is no regular reflection.
diffuse transmission විසරණය සම්ප්‍රේෂණය Transmission in which, on the macroscopic scale, there is no regular transmission.
diffused lighting විසිරුණු ආලෝකකරණය Lighting in which the light on the working plane or on an object is not incident predominantly from a particular direction.
digital computer සංඛ්‍යාංක කොම්පියුටරය Any device capable of solving problems by processing information in discrete form. It operates on data expressed internally in binary code.
digital meter ඩිජිටල් මීටරය Show a discrete reading, in the form of a decimal number, for a given input quantity.
digital to analog converter, D/A converter, D to A converter ඩිජිටල් සිට ඇනලොග් පරිවර්තකය A device or circuit used to convert a digital signal to an analog signal across a pair of terminals.
dimensional analysis මාන විශ්ලේෂණය Analysis using the fact that physical quantities, added to or equated with each other, must have the same equivalent SI Unit.
dimensions of unit ඒකකයේ මානයන් The dimensions of a physical quantity are the powers to which the fundamental units expressing that quantity are raised.
diode දියෝඩ Simplest and most fundamental non-linear circuit element. It is a two terminal device which only allows current to flow in one direction.
dipole ද්විධ්‍රැවය A pair of equal and oppositely charged or magnetized poles separated by a distance.
direct contact සෘජු සබඳතා Contact of persons or livestock with live parts.
direct current, dc සරල ධාරාව An electric current flowing always in the same direction from positive to negative poles.
direct energy conversion සෘජු බලශක්ති පරිවර්තනය Production of electricity from an energy source without transferring the energy to a working fluid or steam.
direct lighting සෘජු ආලෝකකරණය Lighting by means of luminaires with a light distribution such that 90 to 100 per cent of the emitted luminous flux reaches the working plane direct, assuming that this plane is unbounded
disaggregation වර්ගීකරණය The functional separation of the vertically integrated utility into smaller, individually owned business units (i.e. generation, dispatch/control, transmission, distribution).
discharge විසර්ජනය Electrical discharge can occur by the release of the electric charge stored in a capacitor through an external circuit. It can also occur by the breakdown of gaseous dielectrics within solid dielectrics on the application of a field.
discharge current විසර්ජන ධාරාව The surge current that flows through the surge diverter during spark over or operation.
discharge lamp විසර්ජන ලාම්පුව Lamp in which the light is produced, directly or indirectly, by an electric discharge through a gas, a metal vapor, or a mixture of several gases and vapors.
discharge voltage විසර්ජන වෝල්ටීයතාවය residual voltage - The voltage that appears between the line and earth terminals of the surge diverter during the passage of discharge currents.
disconnecting means විසන්ධි කිරීමේ මාධ්‍යයන් A device or group of devices, or other means whereby all the ungrounded conductors of a circuit can be disconnected simultaneously from their source of supply.
disconnector විසන්ධි කරන්න A mechanical switching device which, in the open position, complies with the requirements specified for isolation. A disconnector is otherwise known as an isolator.
discount/interest rate වට්ටම්/පොලී අනුපාතය The discount rate is used to determine the present value of future or past cash flows. The rate accounts for inflation and the potential earning power of money.
discrimination ප්‍රවිචාරණය (වෙනස් කොට සැලකීම​) The ability to discriminate. The characteristics of protective devices must be such that a fault on one circuit will not disconnect another circuit.
disk තැටිය A memory device which uses a magnetic media for the storage of information. Disk, as a term, has expanded into other areas often used to describe the shape of the storage media, that is: floppy disk, compact disk, laser disk, or hard disk.
dispatchable සැලසුම් කළ හැකි Sources of electricity that can be dispatched at the request of power grid operators, according to market needs.
display විදහා පෙන්වීම, සංදර්ශකය A device (usually electrical) for the visual presentation of data or images, usually on a screen.
dissipation උත්සර්ජනය A physical process by which energy becomes not only unavailable but irrecoverable in any form.
distortion විකෘතිය An undesired change in waveform. Distortion is a term that describes abnormal wave shapes.
distributed capacitance ව්‍යාප්ත ධාරණාව Capacitance that exists in a distributed manner between the turns in a coil, or between adjacent conductors in a transmission line.
distributed generation බෙදාහරිනලද විදුලි ජනනය​, විසිරී ඇති විදුලි ජනනය​ A distributed generation system involves small amounts of generation located on a utility's distribution system for the purpose of meeting local peak loads and/or displacing the need to build additional local distribution lines.
distribution ව්‍යාප්තිය The visual representation of a signal on a graph or screen.
distribution බෙදාහැරීම The process of delivering power from the transmission system to the premises. Inside a building, distribution is the process of using feeders and circuits to provide power to devices.
distribution board බෙදාහැරීමේ පුවරුව An assembly containing switching or protective devices (e.g. fuses, circuit breakers, residual current operated devices) associated with one or more outgoing circuits fed from one or more incoming circuits, together with terminals for the neutral and protective circuit conductors. It may also include signalling and other control devices. Means of isolation may be included in the board or may be provided separately.
distribution company, Disco බෙදාහැරීමේ සමාගම The regulated electric utility entity that constructs and maintains the distribution wires connecting the transmission grid to the final consumer. The Disco can also perform other services such as aggregating consumers, purchasing power supply and transmission services for consumers, billing consumers and reimbursing suppliers, and offering other regulated or non-regulated energy services to retail consumers. The "wires" and "consumer service" functions provided by a distribution utility could be split so that two totally separate entities are used to supply these two types of distribution services.
distribution line බෙදාහැරීමේ රැහැන් This is a line or system for distributing power from a transmission system to a consumer. It is any line operating at less than 69,000 volt.
distribution system බෙදාහැරීමේ පද්ධතිය The portion of an electric system (after the transmission system) that is dedicated to delivering electric energy to an end user.
distributor බෙදාහරින්නා A person who distributes electricity to consumers using electrical lines and equipment that he owns or operates.
diversity exchange විවිධත්ව හුවමාරුව Exchange of capacity or energy between systems that have peak loads occurring at different times.
diversity factor විවිධත්ව සාධකය The ratio of the sum of the non-coincident maximum demands of two or more loads to their coincident maximum demand for the same period. Also, The ratio of the sum of the maximum power demands of the subdivisions, or parts of a system, to the maximum demand of the whole system or of part of the system under consideration.
domestic ගෘහ්‍ය, ගෘහස්ථ Relating to the household.
donor පරිත්යාගශීලියා A type of impurity that adds electrons to the atoms of a semiconductor substance.
dot notation තිත් අංකනය A notation used to denote similar ends of mutually coupled coils.
double exponential waveform ද්විත්ව ඝාතීය තරංග ආකාරය A waveform obtained by taking the difference of two exponential waveforms. Usually they have time constants which are highly different to give a waveform with fast rise time and relatively slow overall decay.
double insulation ද්විත්ව පරිවරණය Insulation comprising both basic insulation and supplementary insulation.
down stroke යටි පහර A downward stroke, especially one that is part of a sequence of upward and downward strokes, such as in lightning.
DRAM, Dynamic Random Access Memory ගතික අහඹු ප්‍රවේශ මතකය A type of semiconductor memory that stores data as capacitor charges that need to be refreshed periodically.
drive ධාවකය A machine used to drive or cause rotation in a piece of apparatus.
drop පතනය, බිඳ A small pear-shaped portion of liquid that hangs, falls or adheres to a surface.
droplet බිඳිත්ත A very small drop of a liquid.
dry location වියළි ස්ථානය A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.
DSM ඉල්ලුම පැත්තේ කළමනාකරණය [see demand side management]
dual channel oscilloscope ද්විත්ව නාලිකා ද්‍යෝලනේක්ෂය An oscilloscope that has two independent input connectors and vertical sections and can display them simultaneously.
duality ද්වෛතය Electrical terms may be associated into pairs called duals with similar operating equations. A dual of a relationship is formed by replacing one parameter with the corresponding parameter in an expression. An example is the duality of electricity and magnetism.
duality principle ද්විත්ව මූලධර්මය The duality principle establishes an analogy between similar variables when governed by analogous differential equations. For example, series circuits and parallel circuits are analogous if resistance is replaced by conductance, conductance by resistance, inductance by capacitance or vice versa, current by voltage or vice versa. There is also an analogy between electrical and magnetic circuits.
duct නාලය A closed passageway formed underground or in a structure and intended to receive one or more cables which may be drawn in.
dustproof දූවිලි රහිත Constructed or protected so that dust will not interfere with its successful operation.
dynamo ඩයිනමෝ Device for converting mechanical energy into electrical energy. The mechanical energy of rotation is converted into electrical energy in the form of a current in the armature.
dynamometer instrument ඩයිනමෝමීටර උපකරණය This instrument is also a moving coil instrument except that in this case, the permanent magnet is replaced by a pair of fixed coils to give the fixed field.
dyne ඩයිනය Unit of force in the c.g.s. system. 1 dyne = 10-5 N
E මුලට TOP
e.m.f., emf වි.ගා. බ., විද්යුත්ගාමක බලය electromotive force
earth පොළව, බිමැසිය, බිම, පෘථිවි The conductive mass of the Earth, whose electric potential at any point is conventionally taken as zero.
earth electrode බිමැසි ඉලෙක්ට්රෝඩය A conductor or group of conductors in intimate contact with, and providing an electrical connection to, earth. To maintain the potential near zero and to facilitate the flow of fault currents towards the earth.
earth electrode(s) බිම් ගන්නන ඉලෙක්ට්රෝඩය A conducting element/s buried directly in the earth to maintain the potential near zero and to facilitate the flow of fault currents towards the earth.
earth fault current බිමැසි දෝෂ ධාරාව A current that flows from the faulted phase to earth when there is a line to ground fault.
earth fault loop impedance බිමැසි දෝෂ පුඩුවක් සම්බාධනය The impedance of the earth fault current loop starting and ending at the point of earth fault. The earth fault loop comprises the following, starting at the point of fault: the circuit protective conductor, and the consumer's earthing terminal and earthing conductor, and for TN systems, the metallic return path, and for TT and IT systems, the earth return path, and the path through the earthed neutral point of the transformer, and the transformer winding, and the phase conductor from the transformer to the point of fault.
earth leakage බිමැසි කාන්දුවීම Flow of current from a live conductor to earth in an unintended path through the insulation.
earth leakage circuit breaker, elcb බිමැසි කාන්දු වන පරිපථ කඩනය The elcb is designed to protect both equipment and users from fault currents between the live and earth conductors by detecting the rise in voltage of the frame earth connection with respect to a reference earth.
earth leakage current බිමැසි කාන්දු වන ධාරාව The leakage current from all earthed parts of the product due to imperfect insulation. (also Protective conductor current)
earth wire බිම් කම්බිය A wire that goes down into the mass of the earth.
earthed concentric wiring බිමැසි කේන්ද්‍රීය රැහැන් A wiring system in which one or more insulated conductors are completely surrounded throughout their length by a conductor, for example a metallic sheath, which acts as a PEN conductor.
earthed equipotential zone බිමැසි සමවිභව කලාපය A zone within which exposed conductive parts and extraneous conductive parts are maintained at substantially the same potential by bonding, such that, under fault conditions, the differences in potential between simultaneously accessible exposed and extraneous conductive parts will not cause electric shock.
earthed point of source, artificial neutral ප්‍රභවයේ පෘථිවි ලක්ෂ්‍යය හෝ කෘතිම උදාසීන A reference point for the electrical source and safety devices to correctly work.
earthing බිම් ගැන්නීම Connecting a conductor, or exposed conductive parts of an installation, to the Earth to maintain earth potential.. The Earth is taken as the reference.
earthing conductor බිමැසි සන්නායකය A protective conductor connecting the main earthing terminal of an installation to an earth electrode or to other means of earthing.
earth's magnetic field පෘථිවියේ චුම්බක ක්ෂේත්‍රය It is a magnetic dipole, similar to that of a bar magnet, tilted 11° from the earth's axis of rotation. The magnetic south pole is near the geographic south pole, and the magnetic north pole is near the geographic north pole.
echo දෝංකාරය Effect produced when sound is reflected from a surface sufficiently far away for the reflected sound to be separately distinguishable.
economic dispatch ආර්ථික යැවීම The distribution of total generation requirements among alternative sources for optimum system economy with consideration to both incremental generating costs and incremental transmission losses.
economic efficiency ආර්ථික කාර්යක්ෂමතාව A term that refers to the optimal production and consumption of goods and services. This generally occurs when prices of products and services reflect their marginal costs. Economic efficiency gains can be achieved through cost reduction, but it is better to think of the concept as actions that promote an increase in overall net value (which includes, but is not limited to, cost reductions).
economic energy ආර්ථික ශක්තිය Energy produced and substituted for the traditional but less economical source of energy. Economic energy is usually sold without capacity and is priced at variable costs plus administration costs.
eddy current සුළි ධාරා, එඩී ධාරා Localized induced circulating electric currents set up in metal parts not normally meant to carry currents due to changes in electromagnetic fields.
eddy current loss එඩී ධාරා හානිය, සුළි ධාරා​හානිය power loss in magnetic materials due to eddy currents. This loss is proportional to the square of the thickness and hence can be reduced by the use of laminations.
EF protection, earth fault protection බිමැසි දෝෂ ආරක්ෂාව Intended to protect equipment when an earth fault (failure of insulation fault between a live conductor and earth) occurs.
effective earthing ඵලදායී බිම් ගැන්නීම් Effective earthing avoids having dangerous potentials on the equipment even during electrical faults and also ensures the proper operation of electrical protection equipment during fault conditions. A system is said to be effectively earthed if the factor of earthing does not exceed 80%, and non-effectively earthed if it does.
effective value ඵලදායී අගය, සඵල අගය The effective value of a periodic waveform (current or voltage) is the equivalent constant waveform that delivers the same average power to a resistor as the periodic waveform. It is equal to the rms value of the waveform.
efficacy එලජන්‍යය Relative ability to produce a desired effect.  The amount of energy service delivered per unit of energy input. [often used in reference to lighting systems - see luminous efficacy]
efficiency කාර්යක්ෂමතාව Means of getting the same or better service while using fewer resources. It is also ratio of the output (usually energy) to the same type of input, and expressed as a percentage. A perfect process would have an efficiency of 100%.
efficiency of a machine යන්ත්‍රයක කාර්යක්ෂමතාව The ratio of the output energy to the input energy, usually expressed as a percentage. The efficiency of a machine can never exceed unity or 100%.
elastic modulus or modulus of elasticity ප්‍රත්‍යාස්ථතා මාපාංකය The ratio of the stress to the strain in a given material.
elasticity of demand ඉල්ලුමේ නම්යතාවය The ratio of the percentage change in the quantity demanded of a good to the percentage change in price.
electric capacity විදුලි ධාරිතාව The ability of a power plant to produce a given output of electric energy at an instant in time.
electric charge විද්‍යුත් ආරෝපණය Charge is an electrical property of the atomic particles of which matter is made. The elementary particle called the electron is negatively charged while the proton is equally positively charged so that normal matter is electrically neutral. [Unit: coulomb or C]
electric circuit විදුලි පරිපථය An electrical circuit is an interconnection of electrical elements through which an electrical current flows.
electric current විදුලි ධාරාව An electric current flows through a conductor when there is an overall movement of charge through it and is measured as the time rate of change of charge. [Unit: ampere or A]
electric distribution company විදුලි බෙදාහැරීමේ සමාගම The company that owns the power lines and equipment necessary to deliver purchased electricity to the consumer.
electric field විද්‍යුත් ක්ෂේත්රය The electric field is a region in which a force is exerted on a charged particle. It is defined as the force acting on a unit positive charge placed at that point.
electric flux විද්‍යුත් ස‍්‍රාවය A measure of the electricity coming out from a charged surface. [Unit: coulomb]
electric flux density විද්‍යුත් ස‍්‍රාව ඝනත්වය Electric flux passing through unit area perpendicular to the direction of the flux. [Unit: C/m2]
electric light විදුලි ආලෝකය Illumination produced by the use of electricity. The light sources may be of the incandescent, fluorescent, gas discharge or LED type.
electric motor විදුලි මෝටරය Device for converting electrical energy into mechanical energy in the form of rotation.
electric plant (physical) විදුලි බලාගාරය facility that contains all necessary equipment for converting energy into electricity.
electric polarization විදුලි ධ්‍රැවීකරණය A type of polarisation occurring in a dielectric.
electric power විදුලි බලය Electric power is given by the product of the potential difference and the current.
electric power supplier විදුලි බල සැපයුම්කරු on-utility provider of electricity to a competitive marketplace.
electric shock විදුලි ප්‍රහාරය, විදුලි පහර A dangerous physiological effect resulting from the passing of an electric current through a human body or livestock. Injury to the skin or internal organs that results from exposure to an electrical current. Electric shock occurs when the body becomes a part of an electric circuit. The electrical current must enter the body at one point and leave at another. The human body is a good conductor of electricity. Direct contact with electrical current can be potentially fatal. While some electrical shocks may appear not to be serious, there still may be serious internal damage, especially to the heart and brain.
electric system විදුලි පද්ධතිය All of the elements needed to distribute electrical power. It includes overhead and underground lines, poles, transformers, and other equipment.
electric utility විදුලි උපයෝගීතාව An enterprise engaged in the production and/or distribution of electricity for use by the public.
electric welding විදුලි වෙල්ඩීම In electrical welding, a very high electric current produces the heat needed to melt the material and join two metals together.
electrical degree විදුලි අංශක කෝණය One cycle in a rotating electric machine is accomplished when the rotating field moves from one pole to the next pole of the same polarity. There are 360 electrical degrees in this time period. [i.e. for each pair of poles there are 360 electrical degrees. In a machine with more than one pair of poles, one electrical cycle is completed for each pair of poles in the mechanical cycle; or the electrical degrees per revolution is obtained by multiplying the number of pairs of poles by 360.]
electrical equipment විදුලි උපකරණ Any item for such purposes as generation, conversion, transmission, distribution or utilisation of electrical energy, such as machines, transformers, apparatus_ measuring instruments, protective devices, wiring systems, accessories, appliances and luminaires.
electrical heating විදුලි විද්‍යුත් තාපය​ The heating characteristic of an electric current is used extensively in industrial and domestic heating applications. Electric heating can be obtained from (a) resistance heating, (b) induction heating, (c) eddy current heating (d) dielectric heating, and (e) electric arc heating.
electrical installation, installation විදුලි ස්ථාපනය An assembly of associated electrical equipment supplied from a common origin to fulfil a specific purpose and having certain co-ordinated characteristics.
electrically independent earth electrodes විද්‍යුත් ස්වාධීන පෘථිවි ඉලෙක්ට්‍රෝඩ Earth electrodes located at such a distance from one another that the maximum current likely to flow through one of them does not significantly affect the potential of the other(s).
electricity විදුලිය A form of energy produced by the flow of particles of matter and consists of commonly attractive positively (protons [+]) and negatively (electrons [-]) charged atomic particles. A stream of electrons, or an electric current.
electrochemical breakdown විද්‍යුත් රසායනික බිඳවැටීම In a practical insulation ions may arise from dissociation of impurities or from slight ionisations of the insulating material itself. When these ions reach the electrodes, reactions occur in accordance with Faraday's law of electrolysis, but on a much smaller scale. The products of the electrode reaction may be chemically or electrically harmful and in some cases can lead to rapid failure of the insulation.
electrodynamic විද්‍යුත් ගතිකය The interaction of moving electric charges with magnetic and electric fields.
electrodynamometer විද්‍යුත්ගතිකමානය An instrument dependant on the interaction of the electromagnetic fields of fixed and movable coils. It can measure current, voltage or power in both d.c. and a.c.
electrolysis විද්‍යුත් විච්ඡේදනය Chemical change produced by passing an electric current through a solution containing ions.
electrolyte විද්‍යුත් විච්ඡේද්‍යය An electrically conductive fused salt or a solution where the charge is carried by ionic movement.
electrolytic capacitor (condenser) විද්‍යුත් විච්ඡේදක ධාරිත්‍රකය An electrical capacitor in which one electrode is a metal foil coated with a thin layer of the metal oxide, and the other electrode is a non-corrosive salt paste. The metal foil is maintained positive to prevent the removal of the oxide film by the hydrogen liberated.
electromagnet විද්‍යුත් චුම්බකය Temporary magnet formed by winding a coil of wire round a piece of soft iron, when an electric current flows through the wire, the iron becomes a magnet.
electromagnetic විද්‍යුත් චුම්බක Relating to a magnetic field created by an electric current.
electromagnetic damping විද්‍යුත් චුම්භක පරිමන්දනය Electromagnetic damping is produced by the induced effects when the coil moves in the magnetic field and a closed path is provided for the currents to flow.
electromagnetic field විද්‍යුත් චුම්භක ක්ෂේත්‍රය Electric and magnetic force field that surrounds a moving electric charge.
electromagnetic interference, EMI විද්‍යුත් චුම්භක නිරෝධන A term that describes electrically induced noise or transients, usually at frequencies above 1 MHz.
electromagnetic relay විද්‍යුත් චුම්භක පිළියවනය (රිලේ) A relay controlled by electromagnetic means, to open and close electric contacts.
electromagnetic spectrum විද්‍යුත් චුම්භක සප්තරංජනය The range of frequencies over which electromagnetic radiations are propagated.
electrometer විද්‍යුත්මාන An instrument for measuring electrical potential without drawing any current from the circuit.
electromotive force, emf විද්යුත්ගාමක බලය The source of electrical energy required to produce an electric current in a circuit. Defined as the rate at which electrical energy is drawn from the source and dissipated in a circuit when unit current is flowing in the circuit. [Unit: volt or V]
electron ඉලෙක්ට්‍රෝන An elementary particle having a negative charge and a constituent of all atoms. It has a rest mass of 9.1095x10-31 kg and a charge of 1.60219x10-19 C
electron affinity ඉලෙක්ට්‍රෝන සම්බන්ධතාවය, ඉලෙක්ට්‍රෝන රුචිය The tendency of an atom or molecule to accept an electron and form a negative ion. The halogens have high electron affinities.
electron attachment ඉලෙක්ට්‍රෝ ඈඳුම Electron attachment is the chemical process whereby an electron is attached to a neutral molecule.
electron emission ඉලෙක්ට්‍රෝන විමෝචනය The escape of electrons from the surface of certain materials, stimulated by temperature elevation, radiation or by a strong electric field.
electron gun ඉලෙක්ට්‍රෝන විදුනාව The source of electrons in a cathode ray tube. Consists of a cathode emitter of electrons, an anode with an aperture through which the beam of electrons can pass, and one or more focussing and control electrodes.
electron lens ඉලෙක්ට්‍රෝන කාච A system of electric or magnetic fields used to focus a beam of electrons in a manner analogous to an optical lens.
electron volt ඉලෙක්ට්‍රෝන වෝල්ට් Unit of energy used in dealing with subatomic particles. It is the increase in energy or the work done on an electron when passing through a potential rise of 1 volt. 1 eV = 1.602 x 10-19 J
electronic ballast විද්‍යුත් තුලබරුව A ballast which uses semi-conductor components to increase the frequency and control the operation of a fluorescent lamp. Fluorescent system efficiency is increased due to the higher frequency.
electrostatic විද්‍යුත් ස්ථිතික Relating to an electric field created by an electric charge.
electrostatic generator විද්‍යුත් ස්ථිතික උත්පාදකය A machine designed for the continuous separation of electric charge. An example is the Van de Graaf Generator.
electrostatic meter විද්‍යුත් ස්ථිතික මීටරය These basically work on the principle that the force (or torque) of attraction is proportional to the product of the charges and the force is proportional to the square of the voltage. Thus this meter reads the mean square value and hence is calibrated to read the root mean square value. The electrostatic meter is basically a voltmeter.
ellipsoid ඉලිප්සාභය A solid figure traced out by an ellipse rotating about one of its axes.
email විද්‍යුත් තැපැල, ඉලෙක්ට්‍රොනික තැපෑල Short for electronic mail. A method of exchanging messages between people using electronic devices sent via the internet to a recipient. An email address is required to receive email.
email address විද්‍යුත් ලිපිනය A unique address that identifies an email box to which email messages are delivered over the Internet. Every email address has two main parts: a username and domain name.
embedded generation කාවැද්දූ ජනනය (dispersed generation විසුරුවා හරිනලද ජනනය​ or distributed generation බෙදා හරින ලද ජනනය​) Plant which is connected directly to (embedded within) the utility's distribution network rather than to the high voltage transmission system (or nation grid). They are generally considered to be less than 10-100 MW in capacity and are not centrally planned or dispatched.  They are commonly found on industrial sites and in areas of high renewable energy source such as wind, hydro and solar.
embedded generator කාවැද්දූ විදුලි ජනකය A single generator, or a group of generators, connected to the distribution network of the CEB, at voltages between 400 V and 33 kV.
emergency lighting හදිසි ආලෝකකරණය Lighting provided for use when the supply to the normal lighting fails.
emergency power හදිසි ජවය An independent reserve source of electric power which, upon failure or outage of the normal power source, provides stand-by electric power.
emergency stopping හදිසි නැවැත්වීම Emergency switching intended to stop an operation.
emergency switching හදිසි ස්විච්චිලෑම An operation intended to remove, as quickly as possible, danger, which may have occurred unexpectedly.
emitter විමෝචකය The part of the transistor that is the source of carriers. For npn transistors, the emitter sends free electrons into the base, whereas for pnp transistors, the emitter sends holes into the base.
empirical ආනුභවික Based upon the results of experiment and observation only.
enclosure කුටිය The cabinet or specially designed box or fence or walls in which electrical controls and apparatus are housed, to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.  A part providing protection of equipment against certain external influences and in any direction protection against direct contact.
encoder සංකේතකය A digital circuit that converts information into coded form.
end-use අවසාන භාවිතය The specific purpose for which electric is consumed (i.e. heating, cooling, cooking, etc.).
energized ශක්ත්‍යායනය Electrically connected to a source of voltage
energy ශක්තිය Capacity to do work. [Unit: joule or J].  In the electric power industry, energy is more narrowly defined as electricity supplied over time, expressed in kilowatt-hours.
energy audit බලශක්ති විගණනය A review of the customer's electricity and/or gas usage often including recommendations to alter the customer's electric demand or reduce energy usage. An audit usually includes a visit to the customer's facility.
energy charge බලශක්ති ගාස්තු The amount of money owed by an electric consumer for kilowatt-hours consumed.
energy consumption බලශක්ති පරිභෝජනය The amount of energy consumed in the form in which it is acquired by the user. The term excludes electrical generation and distribution losses outside his point of entry of supply.
energy costs බලශක්ති පිරිවැය Costs, such as for fuel, that are related to and vary with energy production or consumption.
energy efficiency programs බලශක්ති කාර්යක්ෂමතා වැඩසටහන් Programs that reduce consumption.
energy meter බලශක්ති මීටරය Instrument to measure energy, usually a house service meter.
energy source බලශක්ති මූලාශ්රය A source that provides the power to be converted to electricity.
energy use බලශක්ති භාවිතය Energy consumed during a specified time period for a specific purpose (usually expressed in kWh).
engine යන්ත්‍රය, එන්ජිම A device for converting one form of energy into another, especially for converting other forms of energy into mechanical (kinetic) energy.
entrance cable, service entrance conductor පිවිසුම් කේබල්/සේවා පිවිසුම් සන්නායක Cable running outside of a consumer's house into the meter. This cable is owned by the consumer and its maintenance is the consumer's responsibility.
environmental attributes පාරිසරික ලක්ෂණ Environmental attributes quantity the impact of various options on the environment. These attributes include particulate emissions, SO2 or Nox, and thermal discharge (air and water).
EPROM, Erasable programmable read only memory මකා දැමිය හැකි වැඩසටහන්ගත කළ හැකි කියවීමට පමණක් මතකය. A type of programmable read-only memory (PROM) chip that can be erased and re-used. Erasure is caused by shining an intense ultraviolet light through a window that is designed into the memory chip.
equilateral සමතුලිත Having all the sides equal in length. Equilateral triangle is one which has all three sides equal.
equilibrium සමතුලිතතාවය State of balance between opposing forces or effects.
equipment උපකරණ A general term including material, fittings, devices, appliances, luminaires (fixtures), apparatus, and the like used as a part of, or in connection with, an electrical installation.
equipotential bonding සමවිභව බන්ධන Electrical connection maintaining various exposed conductive parts and extraneous conductive parts at substantially the same potential.
equipotential lines සමවිභව රේඛා Equipotential lines are contour lines which trace lines of equal electric potential. Equipotential lines are always perpendicular to the electric field. In 3D, the lines form equipotential surfaces.
equipotential lines and surfaces සමවිභව රේඛා හා තල Lines and surfaces having the same electric potential.
equivalent සමක Term indicating substitutability of items.
erg අර්ගය Unit of work or energy in the c.g.s. system of units. 1 erg = 10-7 J
erosion ඛාදනය In a surface discharge, if the products of decomposition are volatile and there is no residual conducting carbon on the surface, the process is simply one of pitting and is known as erosion. Erosion occurs in organic materials.
error දෝෂය An error is a deviation from the true value of the measured variable.
estimation නිමානය The process of finding an estimate, or approximation that is usable for some purpose even if input data is incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available.
evaporation වාෂ්පීකරණය Conversion of a liquid into vapour, without necessarily reaching the boiling point.
even symmetry, even function ඉරට්ට සමමිතිය A function has even symmetry when its plot is symmetrical about the vertical axis. f(t) = f(-t)
exa (E) එක්සා Decimal multiple prefix corresponding to 1018
exbi (Ei) එක්ස්බි Binary multiple prefix corresponding to gigabinary or 260 or (210) or 1024. [IEC 1998]
excitation උද්දීපනය The addition of energy to a nucleus, an atom or a molecule transferring it from its ground state to a higher energy level. The excitation is the difference in energy between the ground state and the excited state.
excitation සැකෙබිම The application of voltage to an electric device, such as a dgenerator, to produce a magnetic field in the device.
exergy හැකි උපරිම ප්‍රයෝජනවත් වැඩ The exergy of a system is the maximum useful work which can be extracted from a system as it reversibly comes into equilibrium with its environment. Mathematically Energy= Exergy (Available part)+Anergy (Unavailable part).
exponent ඝාතය The number indicating the power of a quantity.
export of electrical energy විදුලි ශක්තිය අපනයනය කිරීම Supply of Electrical Energy by a Generator to the CEB system.
exposed conductive part නිරාවරණය වූ සන්නායක කොටස A normally not live conductive part of equipment which can be touched , but which may become live under fault conditions.
extraneous conductive part බාහිර සන්නායක කොටස A conductive part liable to introduce a potential, generally earth potential, and not forming part of the electrical installation.
extrapolation නිස්සාරණය Filling in values or terms of a series on either side of the known values thus extending the range of values.
extrinsic semiconductor බාහ්‍ය අර්ධ සන්නායකය A semiconductor in which the carrier density results mainly from the presence of impurities or other imperfections, as opposed to an intrinsic semiconductor in which the electrical properties are characteristics of the ideal crystal.
F මුලට TOP
factor of earthing බිම් ගන්නන සාධකය This is the ratio of the highest r.m.s. phase-to-earth power frequency voltage on a sound phase during an earth fault to the r.m.s. phase-to-phase power frequency voltage which would be obtained at the selected location without the fault. This ratio characterises, in general terms, the earthing conditions of a system as viewed from the selected fault location.
FACTS, flexible alternating current transmission system නම්යශීලී ප්‍රත්‍යාවර්ත ධාරා සම්ප්‍රේෂණ පද්ධතිය FACTS is a power electronic based system that provides control of one or more AC transmission system parameters to enhance controllability and increase power transfer capability.
Fahrenheit ෆැරන්හයිට් Temperature scale in which the melting point of ice is taken as 32 oF and the boiling point of water under standard atmospheric pressure (760 torr) as 212 oF. A Fahrenheit degree is 1/180 of the difference between these two temperatures.
farad (F) ෆැරඩ් SI unit of electric capacitance. One farad is defined as the ability to store one coulomb of charge per volt of potential difference between the two conductors.
Faraday cage පැරඩේ කූඩුව An earthed metal screen surrounding a piece of equipment to exclude electrostatic and electromagnetic influences.
Faraday's law of induction පැරඩේ ප්‍රේරණ නියමය Is a basic law of electromagnetism predicting how a magnetic field will interact with an electric circuit to produce an electromotive force (EMF).
fast neutrons වේගවත් නියුට්‍රෝන. Neutrons resulting from nuclear fission that have lost little of their energy by collision and therefore travel at high speeds. It is usual to define neutrons with energies in excessof 0.1 MeV as fast.
fatigue of metals ලෝහවල විඩාව (තෙහෙට්ටුව ) Deterioration of metals owing to repeated stresses above a certain critical value, accompanied by changes in the crystalline structure of the metal.
fault දෝෂය​ A circuit condition in which current flows through an abnormal or unintended path. This may result from ah insulation failure or a bridging of insulation. Conventionally the impedance between live conductors or between live conductors and exposed or extraneous conductive parts at the fault position is considered negligible.
fault current ද්‍යෝෂ ධාරාව A current resulting from a fault.
feasibility study ශක්‍යතා අධ්‍යයනය An analysis that takes all of a project's relevant factors, such as technical and financial considerations, to ascertain the probable success of the project in advance.
feedback ප්‍රතිපෝෂණය, ප්‍රතිපෝෂක A process in which the effect of an action is fed-back to modify the next action.
feeder පෝෂකය All circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device.
femto (f) ෆෙම්ටෝ Decimal sub-multiple prefix corresponding to 10-15.
fermi ෆර්මි A unit of length used in nuclear physics. 1 fermi = 10-15 meter.
fermi-dirac statistics ෆර්මි-ඩිරැක් සංඛ්‍යාලේඛන The branch of statistical mechanics used with systems of identical particles which have the property that their wave function changes sign if any two particles are interchanged.
ferrimagnetism ෆෙරි චුම්භකත්වය The type of magnetism occurring in materials in which the magnetic moments of adjacent atoms are anti-parallel, but of unequal strength, or in which the number of magnetic moments oriented in one direction outnumber those in the reverse direction. Typical ferrimagnetic materials are the ferrites.
ferrites ෆෙරයිට් A group of ceramic materials which exhibit the property of ferrimagnetism. As they are basically electrical insulators, they do not suffer from the effects of eddy currents.
ferroelectrics ෆෙරෝ ඉලෙක්ට්‍රික් Dielectric materials which exhibit properties such as hysteresis which are usually properties of ferromagnetic materials.
ferromagnetism ෆෙරෝ චුම්භකත්වය Ferromagnetism is due to unbalanced electron spin in the inner electron orbits of the elements concerned giving the atoms a resultant magnetic moment. Ferromagnetic materials have very large magnetic permeabilities which vary with the strength of the applied field.
ferroresonance ෆෙරෝ අනුනාදය Resonance resulting when the iron core of an inductive component of an LC circuit is saturated, increasing the inductive reactance with respect to the capacitance reactance.
fertile material සාරවත් ද්‍රව්‍ Isotopes which can be transformed into fissile material by the absorption of neutrons.
FET, field effect transistor ක්ෂේත්‍ර බලපෑම් ට්‍රාන්සිස්ටරය A three terminal semiconductor device that depends on the action of an electric field to control its conductivity. In a "FET" the current is from source to drain because a conducting channel is formed by a voltage field between the gate and the source.
fibre optics තන්තු ප්‍රකාශ විද්‍යාව The use of thin flexible fibres of glass or other transparent solids to transmit light signals, mainly for telecommunications.
field coil ක්ෂේත්‍ර දඟර A coil of wire used for magnetising an electromagnet.
field emission ක්ෂේත්‍ර විමෝචනය The emission of electrons from an unheated surface as a result of a strong electric field existing at that surface.
field intensity, field strength ක්ෂේත්‍ර තීව්‍රතාව, ක්ෂේත්‍ර ප්‍රබලතාව The vector sum of all the forces exerted by an electrical or magnetic field (on a unit mass or unit charge or unit magnetic pole) at a given point in the field.
field ක්ෂේත්‍රය The region in which an electrically charged body (electric field), or a magnetised body (magnetic field) exerts its influence.
field-effect transistor, FET ක්ෂේත්‍ර බලපෑම් ට්‍රාන්සිස්ටරය A three terminal semiconductor device that depends on the action of an electric field to control its conductivity. In a "FET" the current is from source to drain because a conducting channel is formed by a voltage field between the gate and the source.
filament lamp සූත්‍රිකා පහන A lamp in which light is produced by a tungsten filament heated to incandescence by an electric current. The glass bulb enclosing the filament contains a low pressure of inert gas, usually argon.
filament සූතිකා A thin thread. A wire of high melting point heated by the passage of current inside a vacuum tube, incandescent lamp or other similar device.
file ගොනුව A computer resource for recording discrete data in a computer storage device. A file may be designed to store a picture, a written message, a video, a computer program, or a wide variety of other kinds of data.
filter පෙරහන A circuit that is designed to pass signals with desired frequencies and reject or attenuate other frequencies.
final circuit අවසාන පරිපථය The final circuits in an electrical wiring system. A circuit connected directly to current using equipment, or to a socket outlet or socket outlets or other outlet points for the connection of such equipment.
financial attributes මූල්‍ය ගුණාංග Attributes that measure the financial health of the company. Key financial attributes include capital requirements, earnings per share of common equity, capitalization ratios, and interest coverage ratios.
finite element method, FEM පරිමිත අංග ක්‍රමය FEM is a numerical method for solving many engineering problems. FEM is used to compute numerical solutions to partial differential equations governing real systems. Divides the problem domain into a set of subdomains, with each subdomain represented by a set of elemental equations. The global system of equations is solved with initial values of the original problem to obtain a numerical answer.
firm energy ස්ථිර ශක්තිය Power or power-producing capacity covered by a commitment to be available at all times during the period.
fissile material විඛණ්ඩන ද්‍රව්‍ය Isotopes which are capable of undergoing nuclear fission. Sometimes the term is restricted to apply only to isotopes which are capable of undergoing fission upon impact with a slow neutron.
fission විඛණ්ඩනය Division or splitting into two or more parts. Nuclear fission is the process in which a large nucleus splits into two smaller nuclei with the release of energy.
fission products විඛණ්ඩන නිෂ්පාදන Both stable and unstable isotopes produced as a result of nuclear fission.
fixed cost ස්ථාවර පිරිවැය The annual (or sometimes monthly) costs associated with the ownership of property such as depreciation, taxes, insurance, and the cost of capital.
fixed equipment ස්ථාවර උපකරණ Equipment designed to be fastened to a support or otherwise secured in a specific location.
flame ගිනි දැල්ල, ගිනිදැල්ල A hot glowing body of ignited gas that is generated by something on fire.
flash point දැල්ලුම් අංකය The lowest temperature at which a substance gives off sufficient inflammable vapour to produce a momentary flash when a small flame is applied.
flashover පිටිසැණෙළීම Arcing that is caused by the high voltage breakdown of insulation between two conductors, resulting in high current.
flat rate සමවර්ත අනුපාතිකය A fixed charge for goods and services that does not vary with changes in the amount used, volume consumed, or units purchased.
Fleming's rules ෆ්ලෙමින්ගේ නියම If the forefinger, second finger, and thumb of the right hand are extended at right angles to each other, the forefinger indicates the direction of flux, the second finger the direction of the emf and the thumb the direction of the motion in an electric generator. If the left hand is used, the fingers indicate the conditions for an electric motor.
flexible cable නම්යශීලී කේබලය A cable whose structure and materials make it suitable to be flexed while in service.
flexible cord නම්යශීලී රැහැන් ලණුව A flexible cable in which the cross sectional area of each conductor does not exceed 4 mm2.
flexible load shape නම්‍යශීලී බලශක්ති හැඩය The ability to modify the utility's load shape on short notice. When resources are insufficient to meet load requirements, load shifting or peak clipping may be appropriate.
flexible retail pool නම්‍යශීලී සිල්ලර සංචිතයක් A model for the restructured electric industry that features an Independent System Operator (ISO) operating in parallel with a commercial Power Exchange, which allows end-use consumers to buy from a spot market or "pool" or to contract directly with a particular supplier.
flexible wiring system නම්යශීලී රැහැන් පද්ධතිය A wiring system designed to provide mechanical flexibility in use without degradation of the electrical components.
flicker මන්දීප්තිය, චංචලනය Light shines unsteadily, varying rapidly in brightness.
flip flop පිළිපොළ A memory device capable of storing a logic level.
floppy disk නම්ය තැටිය Flexible magnetic disk used for mass storage.
fluctuation උච්චාවචනය A surge or sag in voltage amplitude, often caused by load switching or fault clearing.
fluorescence ප්‍රතිදීප්ත Property of many substances, of absorbing light of one wavelength (or colour) and emitting light of another wavelength (or colour).
fluorescent ප්‍රතිදීපන Defined as emitting light due to absorbing radiation from an external source.
fluorescent lamp ප්‍රතිදීප්ත පහනක් Discharge lamp of the low-pressure mercury type in which most of the light is emitted by a layer of fluorescent material excited by the ultraviolet radiation from the discharge.
flux linkage ස‍්‍රාවය සම්බන්ධතාවය The linking of the magnetic flux with the conductors of a coil. The value obtained by multiplying the number of turns in the coil by the flux passing through the coil.
fluxmeter ස‍්‍රාවමානය An instrument for the measurement of magnetic flux.
flyback පසු පිම්ම The movement of the electron beam back to its initial position between scans in a cathode-ray oscilloscope display.
focal නාභීය Relating to the focus of a lens.
focus නාභිය A control that converges beams to produce a sharp display.
foot ( ft) අඩිය Imperial unit of length. 1 foot = 12 inches = 304.8 mm exactly
foot candle අඩි ඉටිපන්දම Unit of illumination at a point one foot distance from a one candela source. (in the imperial system of units) 1 foot candle = 1 lumen per square foot.
foot lambert අඩි ලැම්බර්ට් Unit of luminance. It is the luminance of a uniform diffuser emitting a foot candle.
foot pound (ft. lb.) අඩි රාත්තල Unit of energy. 1 ft.lb. = 1.356 J
force බලය Any action that tends to maintain or alter the motion of a body or to distort it. [Unit: newton or N]
forced outage බලහත්කාරයෙන් ඇනහිටීම් An outage that results from emergency conditions that requires a component to be taken out of service automatically or as soon as switching operations can be performed. The forced outage can be caused by improper operation of equipment or by human error. If it is possible to defer the outage, the outage becomes a scheduled outage.
form factor ආකෘති සාධකය Ratio of the rms value to the rectified average value in a periodic waveform.
Fortin barometer ෆෝටින් වායු පීඩනමානය (බැරෝමීටරය) A mercury in glass barometer, which used in conjunction with correction tables enables accurate measurement of atmospheric pressure to be made.
forward bias ඉදිරි නැඹුරුව dc voltage applied to a pN junction semiconductor so that the positive terminal of the voltage source connects to the p-type material and the negative terminal to the N-type material. It produces forward current in the circuit.
forward current ඉදිරි ධාරාව Current in a circuit of a semiconductor device due to conduction by majority carriers across the pN junction.
fossil fuel plant පාෂාණීය ධාතු ඉන්ධන බලාගාරය, ෆෝසිල් ඉන්ධන බලාගාරය A plant using coal, oil, gas and other fossil fuel as its source of energy.
fossil fuel පාෂාණීය ධාතු ඉන්ධන, ෆෝසිල් ඉන්ධන​ Any naturally occurring organic fuel, such as petroleum, coal, and natural gas. Remains of organisms embedded in the surface of the Earth, with high carbon and/or hydrogen content, used as fuels.
Fourier analysis ෆූරියෙර් විශ්ලේෂණය The analysis of a complex waveform expressed as a series of sinusoidal functions, the frequencies of which form a harmonic series.
Fourier series ෆූරියර් ශ්‍රේණිය Resolution of a periodic function into its direct component, its fundamental sinusoidal component and an infinite series of harmonic sinusoidal components.
Fourier transform ෆූරියර් පරිණාමනය An integral transformation from the time domain to the frequency domain.
fps system අඩි පවුම් තත්පර පද්ධතිය The foot pound second system of units is an imperial set of units derived from the fundamental units of the foot, the pound mass and the second.
fractal ෆ්‍රැක්ටල් A geometrical shape, each part of which has the same statistical character as the whole. They are useful in modelling structures in which similar patterns recur at progressively smaller scales, and in describing partly random or chaotic phenomena.
free electron නිදහස් ඉලෙක්ට්‍රෝනය An electron which is not attached to an atom, molecule or ion, but is free to move under the influence of an electric field.
freezing point හිමාංකය The temperature of equilibrium between solid and liquid substance at a pressure of one standard atmosphere.
frequency counter සංඛ්‍යාත කවුන්ටරය, සංඛ්‍යාත ගණනය​ A circuit that can measure and display the frequency of a signal.
frequency domain analysis සංඛ්‍යාත වසම් විශ්ලේෂණය Analysis of mathematical functions or signals with respect to frequency, rather than time. Results in the frequency-domain are converted back to a time function.
frequency modulation, FM සංඛ්‍යාන මූර්ජනය (සං ) FM A process whereby the frequency of the carrier is controlled by the modulating signal.
frequency response analysis, FRA සංඛ්‍යාත ප්‍රතිචාර විශ්ලේෂණය Used to calculate the steady-state response due to a sinusoidal load applied to a structure at a single frequency.
frequency response සංඛ්‍යාත ප්‍රතිචාරය The frequency response of a circuit is the variation of its behaviour (voltage or current) with change in frequency.
frequency spectrum සංඛ්‍යාත ප්‍රේක්ෂාවලිය The frequency spectrum of a signal consists of the plots of the amplitude and phases of the harmonics against frequency.
frequency සංඛ්‍යාතය The number of complete cycles of an alternating voltage or current per unit of time. [Unit: hertz or Hz]
fuel adjustment charge ඉන්ධන ගැලපුම් ගාස්තුව A clause in the rate schedule that provides for adjustment of the amount of a bill as the cost of fuel varies from a specified base amount per unit. The specified base amount is determined when rates are approved. This item is shown on all consumer bills and indicates the current rate for any adjustment in the cost of fuel used by the utility. It can be a credit or a debit. The fuel adjustment lags usually lags one or two months behind the actual price of the fuel. For example, the cost of oil in January will be reflected in March's fuel adjustment.
fuel cell ඉන්ධන කෝෂය A electrochemical energy conversion device for producing electricity converting hydrogen and oxygen into electricity. These cells convert chemical energy directly into electrical energy.
fuel diversity ඉන්ධන විවිධත්වය Utility or power supplier that has power stations using several different types of fuel. Avoiding over-reliance on one fuel helps avoid the risk of supply interruption and price spikes.
fuel element ඉන්ධන මූලද්‍රව්‍යය An element of nuclear fuel for use in a nuclear reactor, usually uranium encased in a case.
fuel escalation ඉන්ධන පිරිවැය වැඩිවීම The annual rate of increase of the cost of fuel, including inflation and real escalation, resulting from resource depletion, increased demand, etc.
fuel expenses ඉන්ධන වියදම් Costs associated with the generation of electricity using a fuel.
fuel ඉන්ධන Any substance which is used for producing heat energy, either by means of the release of its chemical energy by combustion or its nuclear energy by nuclear fission.
full load current පූර්ණ භාර ධාරාව The largest current that a motor or other device is designed to carry under specific conditions. Also current at rated conditions.
full wave rectifier පූර්ණ තරංග සෘජුකාරකය A rectifier with a centre tapped secondary windings and two diodes, or a bridge rectifier circuit.
function generator ශ්‍රිත උත්පාදක යන්ත්රය A circuit that produces a variety of electrical waveforms, over a wide range of frequencies
functional earth conductor ක්‍රියාකාරී භූමි සන්නායකය Conductor to be connected to a functional earth terminal.
functional earth terminal ක්‍රියාකාරී පෘථිවි සම්බන්ධතා පර්යන්තය Terminal directly connected to a point of a measuring supply or control circuit or to a screening part which is intended to be earthed for functional purposes.
functional earthing ක්‍රියාකාරී බිම් ගන්නන Connection to Earth necessary for proper functioning of electrical equipment.
functional extra low voltage, FELV ක්‍රියාකාරී අමතර අඩු වෝල්ටීයතාවය An extra low voltage system in which not all of the protective measures required for SELV or PELV have been applied.
functional switching ක්‍රියාකාරී ස්විච්චිලෑම An operation intended to switch 'on' or 'off' or vary the supply of electrical energy to all or part of an installation for normal operating purposes.
fundamental displacement factor, FDF මූලික විස්ථාපන සාධකය Cosine of the phase difference between the fundamental components of voltage and current. For non distorted sinusoids, it is also equal to the power factor.
fundamental unit මූලික ඒකකය Each of a set of unrelated units of measurement, in the SI system of units, which are independantly defined and from which other units are derived.
fuse සේවනූල, විලායකය, ෆියුස් A safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds a specified level.
fuse carrier විලායක වාහකය The movable part of a fuse designed to carry a fuse link.
fuse element විලායකමූලද්‍රව්‍යය A part of a fuse, which is designed to melt and thus open a circuit
fuse link විලායක සබැඳිය Part of a fuse, which comprises a fuse element and a cartridge (or other container) and is capable of being attached to the fuse contacts
fusing current විලායකද්‍රවාංක ධාරාව The minimum current that will cause the fuse element to heat up. melt or blow
fusing factor විලායක ද්‍රවාංක ගුණකය The ratio of the fusing current to current rating
fusion විලයනය, හාවීම The process or result of joining two or more things together to form a single entity.
G මුලට TOP
gain වාසිය A measure of amplification of a device, usually expressed in dB.
gallon (gal) ගැලුම Imperial gallon. A measure of volume. 1 gal = 4.54596 litre
gallon (US) ගැලුම A measure of volume. 1 US gallon = 3.785 litre
galvanised iron ගැල්වනිත යකඩ Iron coated with a layer of zinc to prevent corrosion, usually by hot dipping into the molten metal.
galvanometer විද්‍යුත්ශක්තිමාපකය (ගැල්වනෝමීටරය) An instrument for detecting, comparing, or measuring small electric currents, but not usually calibrated. Usually depends on the magnetic effect produced by an electric current.
gap හිඩැස An empty space or opening in the middle of something or between two things.
gas discharge lamp වායු විසර්ජක පහන Gas-discharge lamp is an artificial light source that generates light by sending an electric discharge through an ionized gas or plasma.
gas turbine plant වායු තලබමරය බලාගාරය A plant in which the prime mover is a gas turbine.
gas turbine වායු තලබමරය Consists typically of an axial-flow air compressor, one or more combustion chambers (where liquid or gaseous fuel is burned). The hot gases are passed to the turbine and expanded to drive the generator and run the compressor.
gas වායු A substance whose physical state (gaseous state) is such that it always occupies the whole of the space in which it is contained.
gaseous වායුමය Relating to or having the characteristics of a gas.
gate කඩුල්ල The terminal of a FET that controls drain current. Also the terminal of a thyristor used to turn on the device.
gauss G ගවුසය An old unit for measuring magnetic flux density (or magnetic induction). 1 G = 10-4 T
generating station, generating plant උත්පාදන බලාගාරය The location of prime movers, electric generators, and auxiliary equipment used for converting mechanical, chemical, and nuclear energy into electric energy.
generating unit උත්පාදන ඒකකය Any combination of physically connected generators, reactors, boilers, combustion turbines, or other prime movers operated together to produce electric power.
generation company, genco උත්පාදනය සමාගම A regulated or non-regulated entity (depending upon the industry structure) that operates and maintains existing generating plants. The Genco may own the generation plants or interact with the short term market on behalf of plant owners. In the context of restructuring the market for electricity, Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a vertically-integrated utility. A company, group or individual who plan to connect or has already connected an Embedded Generator to the CEB distribution network.
generation dispatch and control උත්පාදනය යැවීම සහ පාලනය කිරීම, ජනන ස්ථාපනය හා පාලනය​ Aggregation and dispatching (sending off to some location) generation from various generating facilities, providing backup and reliability of services.
generation උත්පාදනය The process of producing electrical energy by transforming non electrical forms of energy.
generator විදුලි ජනකය A machine for converting mechanical energy into electrical energy.
geometrical ජ්‍යාමිතික Relating to geometry, or according to its methods.
geothermal plant භූතාප බලාගාරය A plant in which the prime mover is a steam turbine driven by steam that derives its energy from heat found in rocks or fluids beneath the surface of the earth. The energy is extracted from naturally occurring geothermal fields or by drilling and/or pumping.
gibi (Gi) ගිබි Binary multiple prefix corresponding to gigabinary or 230 or (210)3 or 10243. [IEC 1998]
giga (G) ගිගා Decimal multiple prefix corresponding to a billion(US) or 109.
gigawatt ගිගාවොට් Unit of electric power equal to one billion watt, or one thousand megawatt.
gilbert ගිල්බට් The c.g.s. unit of magnetomotive force in electrostatic units. 1 gilbert = 10 A.
glare එළිකණ, දීප්තිය Condition of vision in which there is discomfort or a reduction in the ability to see significant objects, or both, due to an unsuitable distribution or range of luminance or to extreme contrasts in space or time.
glow දිලිසුම A steady radiance of light or heat.
glow discharge දීප්තිය විසර්ජනය Electric discharge in which the secondary emission from the cathode is much greater than the thermionic emission.
good conductor සුසන්නායකය A good conductor has loosely bound outer ‘valence’ electrons.
good electrical contact විද්‍යුත් සුස්පර්ශය A good electrical contact in electrical circuit components such as in electrical switches, should have a low electrical contact resistance.
good utility practice හොඳ උපයෝගිතා ක්‍රියාව Methods and practices that are approved by a significant portion of the utility industry.
governor සංයාමකය A device used to measure and regulate the speed of a machine.
graph ප්‍රස්තාරය A diagram showing the relation between two variables, each measured along one of a pair of axes at right angles.
graph of network ජාලයේ ප්‍රස්තාරය The geometric structure of the interconnection of the network elements which completely characterises the number of independent loop currents or the number of independent node-pair voltages necessary to study the network.
graticule ජාලිකාව The CRT grid lines that facilitate the location and measurement of oscilloscope traces.
greenhouse effect හරිතාගාර ආචරණය The greenhouse effect allows solar radiation to penetrate but absorbs the infrared radiation returning to space. It thus increases the mean global surface temperature of the earth caused by gases in the atmosphere (including carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbon).
greenhouse gases හරිතාගාර වායු Greenhouse gases include carbon dioxide, methane, nitrous oxide, hydrocarbons, and chlorofluorocarbons. These provide the greenhouse effect.
grid ජාලකය, කොටුම An interconnected network for delivering electricity from producers to consumers.
grid interconnection ජාලක අන්තර් සම්බන්ධතාවය, කොටුමා අන්තර් සම්බන්ධතාවය A link between CEB Electricity system and Embedded Generator's Electricity System, made for the purpose of Exporting or Importing Electrical Energy.
gross generation දළ උත්පාදනය Amount of electric energy produced by generating units as measured at the generator terminals.
ground fault interruption භූගත දොෂ කැඩීම A unit or combination of units which provides protection against ground fault currents below the trip levels of the breakers of a circuit.
ground fault භූගත දොෂය An undesired path that allows current to flow from a line to ground.
ground loop භූගත පුඩුවක් The condition of having two or more ground references in a common system. When two or more grounds have a potential difference between them, current can flow. This flow of current is a new circuit or loop which can interfere with the normal operation of the system.
ground state භූමි අවස්ථාව The most stable energy state of a nucleus, atom or molecule.
ground භූමිය A conducting connection, either intentional or accidental, between an electric circuit or equipment and the Earth or some conducting body serving in place of the Earth.
grounded neutral භූගත උදාසීන The common neutral conductor of an electrical system which is intentionally connected to earth to provide a current carrying path for the line to neutral load devices.
H මුලට TOP
hairspring කෙහෙදුන්න A slender spiraled recoil spring that regulates the motion of the balance wheel of a timepiece.
half life අර්ධ ආයු කාලය Time required for any specified property to decrease by half.
half wave rectifier අර්ධ තරංග සෘජුකාරකය A type of rectifier that only allows one half-cycle of an AC voltage waveform to pass, blocking the other half-cycle.
half wave symmetry අර්ධ තරංග සමමිතිය A function has half-wave symmetry when one half of its waveform is exactly the negation of the previous half of the waveform.
half-life අර්ධ ආයු The time taken for the activity of a radioactive isotope to decay to half of its original value. In other words the time taken for half the atoms present to disintegrate.
halide හැලයිඩ් Binary compound of one of the halogen elements (fluorine, chlorine, bromine or iodine).
Hall effect හෝල් ආචරණය If an electric current flows in a wire placed in a strong transverse magnetic field, a potential difference is developed across the wire, at right angles to both the magnetic field and the wire.
halogen lamp හැලජන් ලාම්පුව Gas-filled lamp containing a tungsten filament and a small proportion of halogens.
hard disk දෘඩ තැටිය rigid metal magnetic disk used for mass storage.
hardware දෘඩාංග The machines, wiring, and other physical components of a computer or other electronic system.
harmonic ප්‍රසංවාදී, අනුවර්තී A component whose frequency is an integral multiple of the base frequency of the reference waveform.
harmonic analysis අනුවර්තී විශ්ලේෂණය Concerned with the representation of waveforms as the superposition of basic waves to produce the Fourier series.
harmonic distortion ප්‍රසංවාදී විකෘතිය The presence of harmonics that change the AC voltage waveform from a simple sinusoidal to complex waveform. Total harmonic distortion (THD) is a measurement that tells you how much of distortion of a voltage or current is due to harmonics.
harmonic අනුවර්තිය, ප්‍රසංවාදී; හරාත්මක A frequency that is a multiple of the fundamental frequency. For example, 100 Hz is the second harmonic of 50 Hz, 150 Hz is the third harmonic, and so forth.
harmonized standard එකඟවූ ප්‍රමිතිය A standard which has been drawn up by common agreement between national standards bodies notified to the European Commission by all member states and published under national procedures.
heat exchange තාප හුවමාරුව A system used to transfer heat between two or more fluids.
heat rate තාප අනුපාතය A measure of generating station thermal efficiency and generally expressed as BTU per net kWh. The heat rate is computed by dividing the total BTU content of the fuel burned (or of heat released from a nuclear reactor) by the resulting net kWh generated.
heat sink තාප නිවාරකය A mass of metal attached to the case of a transistor or other device to allow the heat to escape more easily and prevent overheating of the transistor or device.
heavy oil ඝන තෙල් The fuel oils remaining after the lighter oils have been distilled off during the refining process. Except for start-up and flame stabilization, virtually all petroleum used in steam plants is heavy oil.
hectare භෙක්ටාරය A measure of large area. 1 hectare = 100 are = 104 m2
hecto (h) භෙක්ටො Decimal multiple prefix corresponding to a hundred or 102. This is not a preferred suffix.
hemisphere අර්ධගෝලය A half of a sphere.
henry (H) භෙන‍්‍රිය SI unit of electric inductance. One henry is equal to the inductance of a closed circuit in which an electromotive force of 1 volt is produced when the electric current in the circuit varies uniformly at the rate of 1 ampere per second.
hertz (Hz) හට්ස් SI unit of frequency. One hertz is equal to one cycle per second.
heuristic ස්වතෝන්වේෂණ, විවරණෝපයෝගී (අත්දැකීමෙන් විනිශ්චය කරන) A method of solving mathematical problems for which no algorithm exists. Involves the narrowing down of the field of search for a solution by inductive reasoning from past experience of similar problems.
hexadecimal ෂඩ්දශම A number system consisting of 16 symbols, namely 0 to 9 and A to E.
high intensity discharge, HID lamp අධිතීව්‍රතා විසර්ජන ලාම්පුව A type of lamp that may consist of mercury vapor, metal halide, high pressure sodium, or low pressure sodium.
high pass filter අධිතරණ පෙරහන (ෆිල්ටරය) A filter designed to pass all frequencies above its cut-off frequency.
high rupturing capacity fuses, HRC fuses ඉහළ කැඩී යාමේ ධාරිතාව විලායකය (ෆියුස්) The HRC fuse is usually a high-grade ceramic barrel containing the fuse element. The barrel is usually filled with sand, which helps to quench the resultant arc produced when the element melts. They are used for high current applications.
high tension , HT අධි වෝල්ටීයතාව High voltage.
high voltage direct current transmission, hvdc transmission අධි වෝල්ටීයතා සරල ධාරා සම්ප්‍රේෂණය Power transmission carried out at high voltage direct current.
high voltage test අධි වෝල්ටීයතා පරීක්ෂණය A test which consists of the application of a specified voltage higher than the rated voltage between windings and frame, or between two or more windings, for the purpose of determining the adequacy of insulating materials and spacing against breakdown under normal conditions. [It is not the test of the conductor insulation of any one winding.
high pressure mercury lamp, high pressure mercury vapour lamp අධි පීඩන රසදිය (වාෂ්ප) ලාම්පුව Mercury vapor lamp, with or without a coating of phosphor, in which during operation the partial pressure of the vapor is of the order of 105pa
high pressure sodium lamp, high pressure sodium vapour lamp අධි පීඩන සෝඩියම් (වාෂ්ප) ලාම්පුව Sodium vapour lamp in which the partial pressure of the vapour during operation is of the order of 104 pa.
histogram ජාලලේඛනය (හිස්ටෝග්‍රෑම්) A type of graphical representation, used in statistics, in which the frequency distribution is expressed by rectangles.
hole සිදුර In a crystal lattice, a point which has been vacated by an electron.
hole හිල, සිදුර, තව්ව, කුහරය A position that needs to be filled because something is no longer there. It is also the name given to a missing electron in certain solids, especially semiconductors.
Hooke's law හූක්ගේ නියමය Within the elastic limit, a strain is proportional to the stress producing it.
horizontal sweep තිරස් පිරිසැරුම The sweep of the electron beam from left to right across the screen of a cathode-ray tube.
horse power, horsepower, hp අශ්ව ජවය, අශ්වබල An imperial unit of power equal to 550 foot-pounds per second (about 0.746 kW), originally related to the power of work horses. A common method of rating motors.
hot spot රත් තැන A small area or spot with a relatively high temperature (usually highest temperature) in comparison to its surroundings.
hot wire ammeter රත් කම්බි ඇමීටරය An ammeter which measures current by sending it through a fine wire, causing the wire to heat and to expand or sag, deflecting a pointer.
hot wire instrument රත් කම්බි උපකරණය An electrical instrument which depends upon the expansion (or change of resistance) of a wire which is heated by the passage of an electric current.
house service meter නිවාස සේවා මීටරය Energy meter at a consumer's premises, measuring power in kWh.
HRC fuse ඉහළ කැඩී යාමේ ධාරිතාව පෙරහන (ෆියුස්) [see high rupturing capacity fuse]
hub කේන්ද්‍රස්ථානය A wiring concentrator used in local area networks.
humidity ආර්ද්‍රතාව A quantity representing the amount of water vapour in the atmosphere.
HV, high voltage අධි වෝල්ටීයතාව Voltage exceeding 1000 V between conductors and 600 V between conductors and earth in low voltage distribution applications.
hydrocarbon හයිඩ්‍රොකාබන් Organic compounds which contain only carbon and hydrogen.
hydroelectric plant ජලවිදුලි බලාගාරය A plant in which the turbine/generators are driven by the kinetic energy of water. One common type of hydropower plant involves using a dam to store water in a reservoir and when released spins a turbine, creating electricity.
hydroelectricity ජල විදුලිය Produced when moving water rotates a turbine shaft and converts potential or kinetic energy to electrical energy with an electrical generator.
hydrometer ද්‍රවමානය, හයිඩ්‍රොමීටරය An instrument for measuring the density of liquids.
hydropower ජල විදුලිය Hydropower or hydroelectricity refers to the conversion of energy from flowing water into electricity. It is considered a renewable energy source because the water cycle is constantly renewed by the sun.
hygrometer ආර්ද්‍රතාමානය, හයිග්‍රෝමීටරය An instrument used to measure the humidity or amount of water vapour in the air.
hysteresis මන්දායනය A physical phenomena wherein the path followed during relieving an applied stress lags that during applying the stress, so that on complete removal of the applied stress a strain remains. This particularly occurs in magnetic materials - the lagging of induced magnetism behind the magnetizing force.
hysteresis curve මන්දායන චක්‍රය A closed curve showing the variation of the magnetic flux density of a ferromagnetic material with the external magnetic field producing it, when this field is changed through a complete cycle.
hysteresis loop මන්දායන වලයය A hysteresis loop shows the relationship between the induced magnetic flux density (B) and the magnetizing force (H). It is often referred to as the B-H loop. The area of the loop corresponds to the energy loss per cycle.
hysteresis loss මන්දායන හානිය Power loss in the magnetic core due to hysteresis.
I මුලට TOP
IC engine අභ්යන්තර දහන එන්ජිම [see internal combustion engine]
IC, integrated circuit ඒකාබද්ධ පරිපථය A type of circuit in which all the components are integrated on a single silicon chip of very small size.
ideal current source පරිපූර්ණ ධාරා ප්‍රභවයක් A source which maintains the source current at a predefined value independent of the load conditions.
ideal dependent source පරිපූර්ණ යැපෙන ප්‍රභවයක් An element in which the source voltage or current is controlled precisely by another voltage or current.
ideal Op Amp පරිපූර්ණ කාරකාත්මක වර්ධකය An operational amplifier (Op Amp)with infinite open-loop gain, infinite input impedance and zero output impedance.
ideal source පරිපූර්ණ ප්‍රභවය An ideal independent source is an active element that provides a specified voltage or current that is completely independent of the remaining circuit elements.
ideal voltage source පරිපූර්ණ වෝල්ටීයතා ප්‍රභවයක් A source which maintains the source voltage at a predefined value independent of the load conditions. In other words the terminal voltage is maintained equal to the internal emf.
identity matrix ඒකක න්‍යාසය A square matrix in which all the elements of the principal diagonal are ones and all other elements are zeros.
IEE wiring regulations IEE රැහැන් රෙගුලාසි Regulations framed for wiring installations for the protection of persons, property and livestock from electric shock, fire, burns and injury from mechanical movement of electrically actuated equipment. It is a joint publication of the IEE/IET and the British Standards Institute.  It is a legal requirement in Sri Lanka.
IEE, IET විදුලි ඉංජිනේරු ආයතනය. Institution of Electrical Engineers/Institution of Engineering and Technology, based in Savoy Place, London, UK.
IEEE විදුලි හා ඉලෙක්ට්‍රොනික ඉංජිනේරු ආයතනය Institute of Electrical and Electronic Engineers. Based in New York, USA.
IESL, Institution of Engineers, Sri Lanka. ශ්‍රී ලංකා ඉංජිනේරු ආයතනය The multidisciplinary professional engineering institution in Sri Lanka based in Wijerama Mawatha, Colombo..
ignition potential ජ්වලන විභවය The electrical potential at which ignition or sparking can occur.
illuminance ප්‍රදීප්තතාව The quantity of light at one point on a surface. It is the quotient of the luminous flux incident on an element of the surface containing the point, and the area of that element. [Unit lux, lx]
illumination ප්‍රදීපනය A measure of the light falling upon a surface. Emission of optical radiation by the process of thermal radiation.
imaginary කල්පිත, අතාත්ත්වික A number that, when squared, has a negative result. Essentially, an imaginary number is the square root of a negative number and does not have a tangible value.
imaginary axis අතාත්ත්වික අක්ෂය The y-axis in the complex plane.
imaginary operator j අතාත්ත්වික ක්‍රියාකරු An multiplier or operator with a magnitude of unity and an anticlockwise rotation of 90o. It also has the value S-1 in the complex domain.
impedance සම්බාධනය The total opposition a circuit offers to the flow of alternating or other current in an electrical circuit. It is the ratio of the voltage to the current. [Unit: ohm , W]
impregnation නිසේවනය The process of filling the pores of paper and similar material in order to improve its insulation properties.
impulse ආවේගය A sudden high amplitude short duration occurrence that can cause a reaction in a dynamic system. For example, a lightning impulse. A disturbance of the voltage waveform that is less than about one millisecond. Voltages can rise to hundreds or even thousands of volt in a very short period of time. An impulse may be additive or subtractive.
impulse function ආවේග ශ්‍රිතය A mathematical function with zero magnitude other than at zero time, where it has an infinite magnitude. The magnitude of an impulse function is defined as its time integral.
impulse generator ආවේග ජනකය An electrical apparatus which produces very short high-voltage or high-current surges. In most impulse generators, certain capacitors are charged in parallel through high series resistances, and then discharged through a combination of resistors and capacitors, giving rise to the required surge waveform (usually double exponential) across the test device.
impulse response ආවේගාත්මක ප්‍රතිචාරය Behaviour of a circuit when the excitation is the unit impulse function. The excitation function may be a voltage or a current.
incandescent තාප දීප්ත Emitting light as a result of being heated.
incandescent (electric) lamp තාපදීප්ත (විදුලි) ලාම්පුව Lamp in which light is produced by means of an element heated to incandescence by the passage of an electric current.
incentive දිරි දීමනා A rebate or some form of payment used to encourage consumers to implement a given demand-side management (DSM) technology. The incentive is usually calculated as the amount of the technology costs that must be paid by the utility to achieve the desired benefit/cost ratio to drive the market.
inch අඟල A measure of length in the imperial system. It is now defined as 1 inch = 25.400 mm
incidence matrix සිදුවීම් න්‍යාසය A connection matrix having elements 1, -1 or 0 dependent on whether a particular connection is present and having the same sign as the reference, has the opposite sign to the reference or not connected at all.
incident පතන An instance of something happening.
incident wave පතන තරංගය An incident wave is a current or voltage wave that travels through a transmission line towards the junction under consideration.
independent power producer, IPP ස්වාධීන බලශක්ති නිෂ්පාදකයා Private entrepreneurs who develop, own or operate electric power plants fueled by alternative energy sources such as biomass, cogeneration, small hydro, waste-energy and wind facilities.  Organisations with generating capacity that are not associated with traditional electricity utilities.
independent system operator, ISO ස්වාධීන පද්ධති ක්‍රියාකරු An entity responsible for the reliable operation of the grid and provision of open transmission access to all market participants on a non-discriminatory basis.
index දර්ශකය The number indicating the power to which the quantity is raised.
indicating instrument ඇඟවුම් මනුව A piece of equipment in which the output is given as the deflection of a needle or the reading of a counter.
indicator සූචකය A thing that indicates the state or level of something, such as an indicator lamp.
indirect contact වක්‍ර සම්බන්ධතා Contact of persons or livestock with exposed conductive parts which have become live under fault conditions.
indirect lighting වක්‍ර ආලෝකකරණය Lighting by means of luminaires with a light distribution such that not more than 10 per cent of the emitted luminous flux reaches the working plane direct, assuming that this plane is unbounded.
indirect utility cost වක්‍ර උපයෝගිතා පිරිවැය Any cost that is not identified with a specific DSM category such as Administration, Marketing, etc.
induced ප්‍රේරිත The process by which an electric or magnetic effect is produced in an electrical conductor or magnetizable body when it is exposed to the variation of a field.
induced emf ප්‍රේරිත වි.ගා.බ. The production of voltage in a coil because of the change in a magnetic flux through a coil.
inductance ප්‍රේරණය The property of a circuit or coil that causes an emf to be set up due to a rate of change of current in the circuit or coil. The constant of proportionality is the inductance.
induction heating ප්‍රේරණ තාපනය A form of heating in which electrically conducting material is heated as a result of the electric currents induced in it by an alternating magnetic field.
induction machine ප්‍රේරණ යන්ත්‍රය Induction machines run at a speed slightly different to synchronous speed as the difference speed, known as slip, is required to generate torque. Induction motors run at sub-synchronous speed where as induction generators run at super-synchronous speed.
induction meter ප්‍රේරණ මීටරය The induction meter depends on the torque produced by the reaction between a flux (whose value depends on the value of the current in one coil) and the eddy currents which are induced in a non-magnetic disc (usually aluminium) by another flux (produced by current in a second coil). Since the action depends on induction, they can be used to measure alternating quantities only. The meter would have a deflection proportional to the product of the two currents.
inductive reactance ප්‍රේරතා ප්‍රතිබාධනය The ratio of the voltage across an inductor to an electric current through it. With alternating current, the current will lag the voltage by an an angle of 900.
inductor ප්‍රේරකය A passive electrical component that stores energy in the form of a magnetic field, usually in a coil.
inertia අවස්ථිතිය A property of an object that causes it to resist changes in speed including reversal. Tendency of a body to preserve its state of rest or uniform motion. For example, inertia causes a motor to rotate at constant speed even with alterning inputs.
infinite අපරිමිත Limitless in extent and impossible to measure or calculate.
infinite busbar අපරිමිත නිය දඬුව A bus bar which has effectively an infinite capacity. Thus keeps constant voltage and frequency independant of load variations. It may behaves like a voltage source with zero internal impedance and infinite rotational inertia.
infinitesimal අත්‍යණුක An indefinitely small quantity. A value approaching zero, but not zero.
infinity අනන්තය A very large quantity greater than any assignable quantity and tending to the inverse of zero.
infrared අධෝරක්ත The form of radiation that has a wavelength just greater than that of the red end of the visible light spectrum. Infrared radiation has a wavelength from about 800 nm to 1 mm, and is emitted particularly by heated objects.
infrared radiation අධෝරක්ත කිරණ Optical radiation for which the wavelengths are longer than those for visible radiation and shorter than those for radio waves. It corresponds to invisible heat radiation.
initial ආරම්භක Existing or occurring at the beginning
initial conditions ආරම්භක අවශ්‍යතා A set of starting-point values imposed upon the variables in an equation that has one or more arbitrary constants.
inlet ඇත්දොර, ආයමුඛය A place or means of entry.
inorganic අකාබනික Not belonging to the large class of carbon compounds which are termed organic.
inphase සමකලාස්ථ Having the same electrical phase angle.
input impedance ප්‍රදාන සම්බාධනය Is the measure of the opposition to current into the load network that is external to the electrical source.
inrush current ආදාන ධාරාව The instantaneous high input current drawn by a transformer or other electrical equipment at turn-on. This arises due to the high initial currents required to magnetise inductors or transformers, or to charge the capacitors.
insertion loss ඇතුළුකිරීමේ හානිය This is the loss that occurs as signals pass through a passive device. Insertion loss occurs in all devices which do not amplify the signal. Also called "feed through loss".
instability අස්ථායිතාව The state of being unstable.
installation ස්ථාපනය An electrical installation is a combination of electrical equipment installed to fulfil a specific purpose and having coordinated characteristics.
installed capacity ස්ථාපිත ධාරිතාව The total generating units' capacities in a power plant or on a total utility system.  The capacity can be based on the nameplate rating or the net dependable capacity.
instantaneous ක්ෂණික Existing or measured at a particular instant.
instantaneous frequency ක්ෂණික සංඛ්‍යාතය The rate of change of phase angle (in rad/s) or additionally divided by 2p (in Hz).
instantaneous value ක්ෂණික අගය The value of an alternating current or voltage at any specified instant in a cycle.
instructed person උපදෙස් ලැබූ අය person adequately advised or supervised by skilled persons to enable him/her to avoid dangers which electricity may create.
instrument උපකරණය An instrument is a device for measuring a physical quantity.
instrument transformer උපකරණ පරිණාමකය (ට්‍රාන්ස්ෆෝමර්) A transformer specifically designed to be used with instruments. Their design ensures high accuracy for the quantity to be measured.
insulated පරිවෘත Covered in non-conducting material to prevent the passage of electricity.
insulation පරිවරණය Material that retards the transmission of electricity, heat, moisture, shock, or sound from one item to another.
insulation co-ordination පරිවාරක සම්බන්ධීකරණය Insulation co-ordination now comprises the selection of the electric strength of the various equipment in relation to the voltages which can appear on the system for which the equipment is intended. The overall aim is to reduce to an economically and operationally acceptable level the cost and disturbance caused by insulation failure and resulting system outages.
insulation failure පරිවාරක ඇනහිටීම Fault between the phase conductor and non-current carrying metallic parts of an electrical equipment, as a result of which high voltages may appear on the frames of equipment and may be dangerous to a person coming in contact with it.
insulation level පරිවාරක මට්ටම It defines the level of insulation with regard to power frequency and with regard to surges. For equipment rated at less than 300 kV, it is a statement of the Lightning impulse withstand voltage and the short duration power frequency withstand voltage. For equipment rated at greater than 300 kV, it is a statement of the Switching impulse withstand voltage and the power frequency withstand voltage.
insulator පරිවාරකය A material or device that inhibits the flow of electrical current (or heat)
integer නිඛිල A whole number (not a fraction) that can be positive, negative, or zero
integrated circuit සංගෘහික පරිපථය A device that contains its own transistors, resistors, and diodes within itself.
integrating meter අනුකලනමානය A meter whose output is proportional to the integrated value of a quantity over time. They are usually with rotating discs where the revolutions correspond to the time of integration.
integrator අනුකලනය An op amp whose output is proportional to the integral of the input signal.
intensity තීව්‍රතාව The measurable amount of a property, such as force, brightness, or a magnetic field.
intercept අන්ත: ඛණ්ඩය; අතුරු ඇරීම The point where the graph of the function crosses, or intercepts the y-axis.
interconnection (electric utility) අන්තර් සම්බන්ධතාවය (විදුලි උපයෝගීතාව) The linkage of transmission lines between two utilities, enabling power to be moved in either direction. Interconnections allow the utilities to help contain costs while enhancing system reliability.
interconnection voltage අන්තර් සම්බන්ධතා වෝල්ටීයතාවය The nominal voltage at which the grid interconnection is made.
interface අතුරුමුහුණත A device or a system through which unrelated entities can interact with each other.
interference නිරෝධන The combination of two or more electromagnetic waveforms to form a resultant wave in which the displacement is either reinforced or cancelled.
interlock අන්තරු බද්ධවිම A device connected in such a way that the motion of one part is held back by another part.
interlocking අතුරුගුළු ලෑම A feature that makes the state of two mechanisms or functions mutually dependent.
intermediate load (electric systems) අතරමැදි භාර (විදුලි පද්ධති) A load in the range from base load to peak load.
intermittency වරෙන් වර බාවය Non continuous availability due to external factors that cannot be controlled. Stopping and starting repeatedly or with periods in between.
intermittent සවිරාම Occurring at irregular intervals; not continuous or steady.
intermittent resources වරින්වර පවත්නා සම්පත් Resources whose output depends on some other factor that cannot be controlled by the utility, such as wind or sun. Thus, the capacity varies by the hour.
internal combustion engine, IC engine අභ්‍යන්තර දහන එජීන්ම An engine in which energy supplied by a burning fuel is directly transformed into mechanical energy by the controlled combustion of the fuel in an enclosed cylinder behind a piston. Usually used in petrol and diesel engines.
internal discharge අභ්‍යන්තර විසර්ජනය An electrical discharge occurring within a material.
international candle අන්තර්ජාතික ඉටිපන්දම [An old unit of luminous intensity, now replaced by the candela.] A point source emitting light uniformly in all directions at one-tenth the rate of the Harcourt pentane lamp burning under specific conditions.
internet අන්තර්ජාලය A global communications network, connecting by cable, wireless and fiber-optic technologies, to provide a variety of information and communication facilities, computers and other devices (such as mobile phones) to the World Wide Web. It consists of interconnected networks using standardized communication protocols.
internet of things, IoT දේවල් අන්තර්ජාලය A network of internet physical objects (embedded with sensors, software and other technologies) with an IP address for internet connectivity. Physical objects include ordinary household objects to sophisticated industrial devices. They have the ability to transfer data over a network without requiring human interaction.
interpolation අන්තර් නිවේශනය An estimation of a value within two known values in a sequence of values.
interruptible loads අතුරුබිඳුම් කළ හැකි භාර Loads that can be interrupted in the event of capacity or energy deficiencies on the supplying system.
interruptible power බාධා කළ හැකි ජවය Power whose delivery can be curtailed by the supplier, usually under some sort of agreement by the parties involved.
interruptible rate බාධා කළ හැකි අනුපාතය Tariff rate for the provision of power at a lower rate to large industrial and commercial consumers who agree to reduce their electricity use in times of peak demand.
interruptor බාධකය A device that automatically breaks an electric circuit if a fault develops.
interval අන්තරය A distinct measure of time, or physical distance, between two things.
intrinsic නිසග, නිජ Belonging to a something by its very nature.
intrinsically safe device සහජයෙන්ම ආරක්ෂිත උපාංගය A device, instrument or component that will not produce any spark or thermal effects under any conditions that are normal or abnormal that will ignite a specified gas mixture.
intrinsically safe නිසගයෙන් නිරාපද A term used to define a level of safety associated with the electrical controls or circuits.
inverse square law ප්‍රතිලෝම වර්ග නියමය States that a specified physical quantity is inversely proportional to the square of the distance from the source of that physical quantity.
inverter අපවර්තකය A device that converts direct current electricity to alternating current either for stand-alone systems or to supply power to an electricity grid.
inverting amplifier අපවර්තක වර්ධක​ (ඇම්ප්ලිෆයර්) Reverses the polarity of the input signal while amplifying it.
ionisation by collision ගැටීමෙන් අයනීකරණ වීම When the kinetic energy of an electron in collision with a neutral gas molecule exceeds the ionisation energy of the molecule, then ionisation can occur.
ionisation අයනීකරණය Process by which an electron is removed or added to an atom, leaving the atom with a nett negative charge (negative ion) or a nett positive charge (positive ion). A process of formation of ions.
ionising අයනීකරණ The process in which an electron is given enough energy to break away from an atom.
irradiance ප්‍රවිකිරණතාව A measurement of solar power and is defined as the rate at which solar energy falls onto a surface.
irradiation ප්‍රවිකිරණය Process by which an object is exposed to radiation.
irradiation ප්‍රකිරණය Exposure to radiation of any kind.
irreversible process අපතිවර්ත්‍ය ක්‍රියාවලිය A process that is not fully reversible.
islanded operation දූපත් මෙහෙයුම The situation that arises when a part of the electrical system is disconnected from the main grid and is energised by one or more generators connected to it.
islanding දූපතක් කිරීම The process whereby a power system is separated into two or more parts, with generators supplying loads connected to some of the separated systems
isochronous governor සමකලාවර්ත සංයාමකය A governor that maintains the same speed in the controlled machine regardless of the load.
isochronous සමකලාවර්ත Isochronous means that the governer keep always the same frequency. Droop is used to guarantee a fall of frequency according to the load.
isokeraunic level සම අශනි මට්ටම, ගිගුරුම් සහිත දින නියත මට්ටම Contours of constant keraunic level or thunder days. The keraunic (or ceraunic) level is the average number of days per year when thunder is heard in a given area. A map of isokeraunic contours is used to give an estimate of relative lightning occurrences.
isolated system ඒකලිත පද්ධතිය A physical system that does not interact with other systems as other systems are considered to be so far removed.
isolation transformer හුදකලා පරිණාමකය (ට්රාන්ස්ෆෝමර්) A transformer with physically separate primary and secondary windings. An isolation transformer does not transfer unwanted noise and transients from the input circuit to the output windings.
isolation ඒකලනය The degree to which a device can separate the electrical environment of its input from its output, while allowing the desired transmission to pass across the separation. A function intended to cut off for reasons of safety the supply from all, or a discrete section, of the installation by separating the installation or section from every source of electrical energy.
isolator හුදකලාව Mechanical switching device which, in the open position, complies with the requirements specified for isolation. An isolator is otherwise known as a disconnector.
isothermal සමෝෂ්ණ Possessing the same or constant temperature
isotropic සමාවර්තනික Substances exhibiting uniform properties throughout, in all directions.
IT system IT පද්ධතිය A system having no direct connection between live parts and Earth, the exposed conductive parts of the electrical installation being earthed.
iteration පුනඃකරණය Repetition of a computational procedure applied to the result of a previous application, typically as a means of obtaining successively closer approximations to the solution of a problem.
J මුලට TOP
J-K flip flop J-K පිළිපොළ A type of flip-flop that can operate in the 'no change', 'set', 'reset' and 'toggle' modes.
joint, junction සන්ධිය A point at which two or more things or circuit elements are joined.
joule (J) ජූල් SI unit of work or energy. One joule is defined to be the work done by a force of one newton acting to move an object through a distance of one meter in the direction in which the force is applied.
Joule's equivalent ජුල් සමකය The amount of energy necessary to raise the temperature of a given mass of water by 1 degree Celsius. It has a value of 4186 Joules/kilocalorie.
junction box සන්දි පෙට්ටිය An enclosure where conductors or wires an spliced or terminated.
junction diode සන්දි දියෝඩය Diode consisting of a pN junction and suitable connecting leads.
K මුලට TOP
Karnaugh map කර්නෝග් අනුරූපණය An arrangement of cells representing the combinations of variables in a Boolean expression and used for a systematic simplification of the expression.
kelvin (K) කෙල්වින් The kelvin is unit of thermodynamic temperature. It is a fundamental unit. It is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water [1967]
Kelvin double bridge කෙල්වින් ද්විත්ව සේතුව It is a double bridge arrangement, which is an extension of the Wheatstone bridge, for the precise measurement of low resistance (below 1 ohm). The errors due to contact and lead resistances are eliminated by the additional bridge incorporated.
keraunic level ගිගුරුම් සහිත දින Number of days in the year in which thunder is heard.
kibi (Ki) කිබි Binary multiple prefix corresponding to kilobinary or 210 or (210)1 or 1024. [IEC 1998]
kilo (k) කිලෝ Decimal multiple prefix corresponding to a thousand or 103.
kilogram (kg) කිලෝග්‍රෑම් The kilogram is the SI unit of mass. It is a fundamental unit. It is equal to the mass of the international prototype of the kilogram preserved in France [1901]
kilovolt ampere, kVA කිලෝ වෝල්ට් ඇම්පියර් The practical unit of apparent power, which is 1,000 volt-ampere.
kilowatt-hour (kWh) කිලෝවොට් පැය The standard unit of electricity supplied to the consumer. Equal to 1 kilowatt acting for 1 hour. 1 kWh = 3.60 x 106 J
kinetic energy චාලක ශක්තිය Energy which a body possesses by virtue of being in motion.
Kirchoff's current law, KCL කර්චොෆ්ගේ විද්‍යුත් ධාරා නියමය States that the algebraic sum of the currents entering a node (or a closed boundary) is zero.
Kirchoff's voltage law, KVL කර්චොෆ්ගේ වෝල්ටීයතා නියමය States that the algebraic sum of the voltages around a closed loop is zero.
klydonograph ක්ලයිඩනොග්‍රාපය A device that records the presence of high voltage surges. across a combination of rod and plate electrones. on a photographic film. An instrument used for the detection and recording of the occurrence of lightning in transmission lines.
knife edge balance පිහිදාරය තුලාව A wedge of metal used as a low-friction fulcrum for a balancing beam or lever.
L මුලට TOP
laboratory පරීක්ෂණාගාරය A room or building equipped for scientific experiments, research, or teaching.
lag විලම්බය, අවුරනවා Used to mean that current lags the voltage.
lag පමාව, විලම්බය, අවුරනවා The time delay between the output signal and the response time of the receiver of the signal.
lag ප්‍රමාද කෝණය The angle delay between voltage signal and the corresponding current signal.
lagging ඇවිරීම, විලම්බනය A lagging waveform is one that occurs after another. It is usually measured as an angle, but may also be measured as the corresponding time period. Is the property of an electrical circuit in which the current flowing through the circuit will be lagging the voltage in an alternating power system.
lagging load පසුගාමී විදුලි හාරය An inductive load with current lagging voltage.
Lagrange multiplier ලග්රාන්ජ් ගුණය The method of Lagrange multipliers is a strategy for finding the local maxima and minima of a function subject to equality constraints.
lambert ලැම්බර්ට් An old unit of luminance. The luminance of a uniform diffuser of light which emits one lumen per square centimetre. 1 lambert = 10-4 lux
Lambert's cosine law ලැම්බට් කොසයින් නියමය Lambert's cosine law states that the luminous intensity observed from an ideal diffusely reflecting surface is directly proportional to the cosine of the angle θ between the direction of the incident light and the normal to the surface.
lamination ආස්තරණය, තුනී ස්ථර Thin layers or sheets. Steel rolled into thin sheets and used to build up a magnetic core, such as in a transformer. Instead of having one solid iron magnetic core, the magnetic path is split up into many thin paths to reduce eddy currents.
lamp පහන A device for giving light, usually consisting of an electric bulb together with its holder and shade.
LAN, Local Area Network ප්‍රාදේශීය ජාලය A data communications system confined to a certain area. The area served may consist of a single building, or a cluster of buildings.
Laplace transform ලප්ලාස් පරිණාමනය, ලප්ලාස් පරිණාමිතය An integral transform, named after its inventor Pierre-Simon Laplace, and transforms a function of a real variable t (usually time) to a function of a complex variable s. Laplace transform converts linear differential equations to algebraic equations for easy solution. Used to analyse transients in circuits.
laser ලේසර් (විකිරණ උත්තේජනය කිරීමෙන් ආලෝක විස්තාරණය) Acronym for Light Amplification by Stimulated Emission of Radiation. The laser produces a powerful, highly directional, monochromatic, and coherent beam of light.
laser, laser beam ලේසරය, ලේසර කදම්බය An intense beam of coherent monochromatic light (or other electromagnetic radiation) by stimulated emission of photons from excited atoms or molecules. The term "laser" is an acronym for "light amplification by stimulated emission of radiation".
latch තරංකය (ඔරලෝසු රහිත ෆ්ලිප්-ෆ්ලොප් ) A non-clocked flip-flop.
latent heat ගුප්ත තාපය Quantity of heat required to effect a change of state of a unit mass of a substance from solid to liquid (latent heat of fusion) or from liquid to vapour (latent heat of vaporisation) without change of temperature.
lattice දැලිස් A regular network of fixed points arranged in a geometrical pattern of straight lines.
layer ස්තරය, තට්ටුව A layer is one of the different levels at which you can place something.
LCD ද්රව ස්පටික සංදර්ශකය. [see Liquid crystal diode ]
leach ක්ෂීරණය To drain away from soil, or similar material by the action of percolating liquid, especially rainwater.
leaching කාන්දුවීම Washing out of a soluble constituent of a material.
lead accumulator ඊයම් ඇකියුමිලේටරය A secondary cell, or accumulator, in which the electrodes are made of lead and the electrolyte consists of dilute sulphuric acid. Electrical energy is not generated within the cells themselves, but previously stored, or charged, using an external source.
lead ඉදිරි කෝණය The angle advance between voltage signal and the corresponding current signal.
leader stroke නියමු පහර The propagation of a leader carrying down charge from a cloud to ground in a lightning discharge.
leading load ඉදිරි විදුලි භාර A capacitive load with current leading voltage.
leading phase ප්‍රමුඛ කලාව A leading phase is one that occurs before a reference phase or another. It is usually measured as an angle.
leading පුරෝගාමී, ප්‍රමුඛ leading refers to an alternating current in which the peak occurs before the associated voltage peak..
leads නියමු Leads are used to connect together two components or a component to a piece of equipment.
leak කාන්දු To accidentally lose or admit contents, especially liquid or gas, through a hole or crack.
leakage current කාන්දුවන ධාරාව Electric current in an unwanted conductive path under normal operating conditions.  Current flowing from the enclosure, or parts thereof, accessible to the operator in normal use, through an external conductive connection other than the protective earth conductor to earth or to another part of the enclosure. The current that flows from either an ac or dc circuit in an equipment to the frame or to the earth.
leakage factor කාන්දුවන සාධකය Ratio of the total flux to the useful flux is defined as the leakage factor. It has a value of around 1.2 for electrical machines.
leakage inductance කාන්දුවන ප්‍රේරණය A small inductance associated with the flux of a transformer winding which are not magnetically coupled to the other windings of the transformer.
leased line කල්බදු රැහැන් A dedicated circuit, typically supplied by the telephone company, that permanently connects two or more user locations. These lines are used to transmit data.
least cost alternatives අවම පිරිවැය විකල්ප The lowest cost option for providing for incremental demands. In least cost planning to serve electric demands, the least cost alternatives are often construed broadly to include demand-side management as well as various generation and purchased power options.
least squares අඩුතම වර්ග Overall solution minimizes the sum of the squares of the residuals made in the results of each equation.
LED, light emitting diode ආලෝක විමෝචක දියෝඩ emits light when current is passed through it. A semiconductor light source that radiates light such as red, green, yellow and white, or invisible light such as infra red.
left hand rule වමත් නීතිය If the thumb and first two fingers of the left hand are held mutually at right angles to each other and if the index finger indicates the direction of field, and if the middle finger indicates the direction of current flowing through the conductor, then the thumb indicates the direction of force exerted on the conductor.
lens කාච Any device which causes a beam of rays to converge or diverge on passing through it.
Lenz's law ලෙන්ස් නියමය States that the direction of an induced current is such as to oppose the change in the magnetic field that produces it.
Leyden jar ලෙඩන් සරාව An early device (invented 1745) for storing electric charge consisting of a glass jar lined inside and out with tinfoil and having a conducting rod connected to the inner foil lining and passing out of the jar through an insulated stopper. Benjamin Franklin used a Leyden jar in his famous kite experiments with lightning.
Lichtenberg figures ලිචන්බග් රූප Branching tree-like patterns that are created by the passage of high voltage electrical discharges along the surface, or through dielectrics.
life time ආයුෂ කාලය The duration of a thing's existence or usefulness.
light oil සැහැල්ලු තෙල් Lighter fuel oils distilled off during the refining process. Virtually all petroleum used in internal combustion and gas turbine engines use light oil.
light year ආලෝක වර්ෂය A measure of astronomical distances. 1 light year = 9.461 x 1015 m
light ආලෝකය Any radiation capable of causing a visual sensation direct i.e. Visible electromagnetic radiation in the wavelength range 400 to 700 nano meter.
lighting arrester අකුණු නිවාරකය A device used on electric power systems and telecommunication systems to protect the insulation and conductors from the damaging effects of lightning. A device used to pass large impulses to ground. It is vital that this device be placed upstream from the equipment to be protected.
lighting conductor අකුණු සන්නායකය A metal rod fixed to an exposed part of a building (or other tall structure) to divert lightning harmlessly into the ground.
lightning discharge අකුණු විසර්ජනය A naturally occurring electrostatic discharge from a thundercloud, either within it, or from it to the atmosphere or to the earth, causing the instantaneous release of a great amount of energy.
lightning flash අකුණු එළිය A typical lightning flash culminates in the formation of an electrically conducting plasma channel through the air and producing a brilliant flashe of visible light.
lightning protection අකුණුවලින් ආරක්ෂාව A system to enable the high electrical discharge due to lightning to be conducted safely to earth by one or more conductors.
lightning rod අකුණු කූර A grounded metallic rod set up on a structure (like a building) to protect it from lightning.
lightning අකුණු A form of visible electric discharge between thunder clouds or thunder cloud to air or between a thunder cloud and the earth. Ninety percent of all lightning never touches the ground - it occurs inside the thunder cloud or jumps from cloud to cloud or to air.
line conditioner විදුලි රැහැන් සකසනය line conditioner contains multiple protection devices in one package to provide, for example, electrical noise isolation and voltage regulation.
line spectrum වර්ණාවලි රේඛාව A spectrum consisting of discrete lines, rather than continuous.
line to line අදියර සන්නායකයක් සිට අදියර සන්නායකයකට A term used to describe a given condition between conductors of a multiphase feeder.
line to neutral අදියර සන්නායකයක් සිට උදාසීන සන්නායකයකට A term used to describe a given condition between a phase conductor and a neutral conductor.
line voltage අදියර සන්නායකයක් සිට අදියර සන්නායකයකට The voltage between two lines (or phases) of a three phase system is defined as the line-to-line voltage or more commonly as the line voltage. For a balanced three phase system, the line voltage is Ö3 times the phase-to-neutral voltage.
line විදුලි මාර්ගය A line is a system of poles, conduits, wires, cables, transformers, fixtures, and accessory equipment used for the distribution of electricity to the public.
line සන්නායක කම්බිය A designation of one or more power-carrying conductors for power distribution. The brown (or red) wire is the line conductor, the blue (or black) wire is the neutral, and the green-yellow (or green) wire is the ground. The voltage difference between the line conductor and the neutral is the supply voltage.
linear රේඛීය Arranged in or extending along a straight or nearly straight line.
linear circuit රේඛීය පරිපථය One whose output is linearly related to the input. A circuit which obey's Ohm's law.
linear motor රේඛීය මෝටරය A form of motor (normally induction motor) in which the stator and rotor are linear instead of cylindrical and parallel instead of coaxial.
liquid ද්‍රවය A substance that flows freely but is of constant volume, such as water or oil. Liquids assume the shape of the vessel containing them, other than the top surface which will assume a horizontal position when free to air. They are only slightly compressible.
liquid crystal display, LCD ද්රව ස්පටික සංදර්ශකය Displays made from liquid crystals which usually change from transparent to opaque in the presence of electric or magnetic fields. They are commonly used in digital displays.
Lissajous figures, Lissajous pattern ලිසාජු රූප, ලිස්සාජස් රටාව Characteristic looped figures traced out by a point undergoing two independent simple harmonic motions at right angles with frequencies in a simple ratio. The pattern appearing on an oscilloscope when harmonically related signals are applied to the horizontal and vertical inputs of an oscilloscope.
live part සජීවී කොටස A conductor or conductive part intended to be energised in normal use, including a neutral conductor but, by convention, not a PEN conductor.
live wire සජීව කම්බිය Live wire is the wire with standard voltage(also called phase wire), while the neutral wire has zero or negligible voltage.
load භාර, විභර An electrical load is an electrical device that consumes active electric power.
load භාර Any passive electrical device connected to a power source may be called by the general term of "load". It is the amount of electric power delivered or required at any specific point or points on a system. The requirement originates at the energy consuming equipment of the consumers. [Unit: kW or MW]
load center භාර මධ්‍යස්ථානය A limited geographical area where large amounts of power are used by consumers.
load diversity භාර විවිධත්වය The load condition that exists when the peak demands of a variety of electric consumers occur at different times.
load duration curve, LDC භාර කාල වක්‍රය A curve that displays load values on the horizontal axis in descending order of magnitude against percent of time (on the vertical axis) the load values are exceeded.
load factor භාර සාධකය The ratio of the average load supplied (kW) during a designated period to the peak or maximum load (kW) occurring during that period.
load flow භාර ප්‍රවාහය Steady state analysis of power system network. Load flow study determines the operating state of the system for a given loading..
load forecast භාර පුරෝකථනය Estimate of electrical demand or energy consumption at some future time.
load line පැටවුම් රේඛාව Locus of instantaneous operating points used to find the exact operating values of voltage and current.
load management භාර කළමනාකරණය Techniques used by utilities to manage daily and/or seasonal fluctuations in customer demand. Managing the level and shape of demand for electrical energy so that demand conforms to present supply situations and long-run objectives and constraints.
load profile භාර පැතිකඩ Information on a consumer's usage over a period of time, sometimes shown as a graph.
load shape භාර හැඩය A curve showing power (kW) supplied (on the horizontal axis) plotted against time of occurrence (on the vertical axis), and illustrating the varying magnitude of the load during the period covered.
load shedding භාර වැගිරීම Action to reduce the connected load, especially the interruption of an electricity supply to avoid excessive load on the generating plant which may cause it to trip.
load shifting පැටවීමේ සීරුමාරු A load shape objective that involves moving loads from peak periods to off-peak periods. If a utility does not expect to meet its demand during peak periods but has excess capacity in the off-peak periods, this strategy can be considered.
loading effect භාර බලපෑම Connection of a meter (an ammeter in series or a voltmeter in shunt) to a circuit to make a measurement alters the original circuit in that it draws some energy from the circuit. The error caused is known as the loading effect.
local lighting ස්ථානික ආලෝකනය Lighting for a specific visual task, additional to and controlled separately from the general lighting.
location of fault දෝෂ නිවේෂණය Process of locating faults where the fault cannot be seen, such as insulation faults in underground cables.
lockout පිටගුහ ලෑම A mechanical device which may be set to prevent the operation of a push-button or other device.
locus පථය A curve formed by all the points satisfying a particular relationship according to mathematically defined conditions.
lodestone කාන්දම් ගල A piece of naturally magnetized mineral, such as magnetite, able to be used as a magnet.
logarithm ලඝුගණකය A quantity representing the power to which a fixed number (the base) must be raised to produce a given number. The chief advantage is that multiplications and divisions are converted toadding and subtracting logarithms.
logic circuit තාර්කික පරිපථය A circuit that behaves according to a set of logic rules.
logic level තාර්කික මට්ටම State of a voltage variable. States HIGH and LOW correspond to the two usable voltage levels of a digital device.
LOI, letter of intent අභිප්‍රාය ලිපිය Issued by CEB to a Generating Company to signify CE13's intent to purchase power from a Generating Company at a particular location.
LOM protection, loss of mains protection ජව මූලික ආරක්ෂාව නැතිවීම Used to detect a loss of the main utility electricity supply (including under voltage, over voltage and frequency protection) and prevent power islanding.
loop පුඩුව A loop is a closed path of a circuit formed by starting at a node, passing through a set of nodes, and returning to the starting node without passing through any node more than once.
loop current පුඩු ධාරාව A component of current common to the complete loop.
loop or mesh පුඩුව හෝ දැල A closed path of elements in a circuit.
loss හානිය Power loss or energy loss refers to convertion of part of the energy to a non-useful form, and is effectively lost.
loss angle හානි කෝණය Angle of deviation of the current from the ideal current for a dielectric for a sinusoidal input.
loss factor හානි සාධකය A factor which defines the loss component of a dielectric.
loss of load probability, LOLP පැටවීමේ සම්භාවිතාව නැතිවීම A measure of the probability that system demand will exceed capacity during a given period; this period is often expressed as the expected number of days per year over a long period, frequently taken as ten consecutive years. An example of LOLP is one day in ten years.
loss tangent හානි ටැන්ජනය The loss factor, which also corresponds to the tangent of the loss angle.
losses හානි The general term applied to energy (kWh) and capacity (kW) lost in the operation of an electric system. Losses occur principally as energy transformations from kWh to waste-heat in electrical conductors and apparatus. This power expended without accomplishing useful work occurs primarily on the transmission and distribution systems.
low noise earth අඩු ශබ්ද භූමිය An earth connection in which the level of conducted or induced interference from external sources does not produce an unacceptable incidence of malfunction in the data processing or similar equipment to which it is connected. The susceptibility in terms of amplitude/frequency characteristics varies depending on the type of equipment.
low pass filter අවච තැරුම් පෙරහන A filter designed to pass only frequencies from d.c. up to the cut-off frequency.
low-pressure mercury lamp, low-pressure mercury vapor lamp අඩු පීඩන රසදිය (වාෂ්ප) ලාම්පුව Mercury vapor lamp, with or without a coating of phosphor, in which during operation the partial pressure of the vapor does not exceed 100 pa.
low-pressure sodium lamp, low-pressure sodium vapor lamp අඩු පීඩන සෝඩියම් (වාෂ්ප) ලාම්පුව Sodium vapor lamp in which the partial pressure of the vapor during operation does not exceed 5 pa.
lumen (lm) ලුමනය SI unit for measuring the flux of light. One lumen is equal to the luminous flux emitted in unit solid angle (steradian) by uniform point source having a luminous intensity of 1 candela.
luminaire efficiency ආලෝකකරණ සවිකෘත කාර්යක්ෂමතාව The ratio of total lumen output of a luminaire to the lumen output of the lamps, expressed as a percentage.
luminaire ආලෝකකරණ සවිකෘත Apparatus that distributes, filters or transforms the light given by a lamp or lamps and which includes all the items necessary for fixing and protecting these lamps and for connecting them to the supply circuit.
luminescence සන්දීප්තිය A spontaneous emission of light by a substance not resulting from heat. Substances which emit luminescent light are called phosphors.
luminosity දීප්තිය The total energy per unit time emitted by an object. For example, the Sun's luminosity is equivalent to 3.8 x 1026 W.
luminous efficacy ආලෝකවත් සඑලත්වය Quotient of the luminous flux emitted by a source and the power consumed. [Unit lumen per watt, lm/W] Visible light output of a luminary measured relative to power input.
luminous flux දීප්ත ස‍්‍රාවය The quantity derived from radiant flux by evaluating the radiation according to its action upon the standard photometric observer. [Unit lumen, lm].
luminous intensity distribution දීප්තිමත් තීව්‍රතා ව්‍යාප්තිය Distribution of the luminous intensities of a lamp or luminaire in all spatial directions.
lumped parameter පිඩු පරාමිතිය Simplifies the description of the behaviour of spatially distributed physical systems into a topology consisting of discrete lumped entities that approximate the behaviour of the distributed system under certain assumptions.
lumped representation පිඩු නිරූපණය In ideal transmission line, resistance,inductance, leakage conductance and capacitance are distributed parameters. However for short and medium length lines, all parameters are assumed to concentrated at a few points and represented by T or π circuit.
lux (lx) ලක්සය SI unit for measuring the illumination of a surface. One lux is defined as an illumination of one lumen per square meter.
LV, low voltage අඩු වෝල්ටීයතාවය Voltage not exceeding 1000 V between conductors and 600 V between conductors and earth.
M මුලට TOP
machine යන්ත්‍රය A device that will change one form of energy to another form of energy.
macroscopic මහේක්ෂ Objects or phenomena that are large enough to be visible with the naked eye, without magnifying optical instruments.
magnetic චුම්බක Exhibiting or relating to magnetism.
magnetic field චුම්බක ක්ෂේත්‍රය A region of space that surrounds a moving electrical charge or a magnetic pole, in which the electrical charge or magnetic pole experiences a force that is above the electrostatic ones associated with particles at rest.
magnetic flux චුම්බක ස‍්‍රාවය A measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field. [Unit: weber]
magnetic hysteresis චුම්බක මන්දායනය A characteristic of ferromagnetic materials, consisting of the lack of retraceability of the initial magnetization curve when the magnetic field is relaxed.
magnetic mechanism චුම්බක උපක්‍රමය The magnetic mechanism uses a solenoid with an iron piece to operate the circuit breaker in the event of an overcurrent.
magnetic reluctance චුම්බක විරමණය The obstruction offered by a magnetic circuit to the magnetic flux. Magnetic reluctance in a magnetic circuit is analogous to electrical resistance in an electrical circuit, with magnetic flux corresponding to electric current, magnetomotive force corresponding to electromotive force and magnetic reluctance corresponding to electrical resistance.
magnetic saturation චුම්බක සන්තෘප්තිය Saturation is the state reached when an increase in applied external magnetic field H cannot increase the magnetization of the material further, so the total magnetic flux density B more or less levels off and continues to increase very slowly due to the permeability of free space.
magnetic shield චුම්බකීය වළහනය A protection from the influence of an external magnetic field.
magnetic susceptibility චුම්බක ග්‍රාහිතාව A dimensionless proportionality constant that indicates the degree of magnetization of a material in response to an applied magnetic field. It is defined as the ratio of magnitude of the internal polarization divided to the strength of the external field.
magnetisation චුම්බකනය The process of making a substance temporarily or permanently magnetic, as by insertion in a magnetic field.
magnetisation curve චුම්බක වක්‍රය The relationship between the magnetic flux density and the applied magnetic field (or the magnetic flux and the applied mmf) is called the magnetisation curve.
magnetising current චුම්බකන ධාරාව The total current that flows into the primary of a transformer when the transformer is energized at a specific voltage and frequency, with the secondaries on open circuit.
magnetism චුම්භකත්වය The property of certain materials to attract iron and other magnetic materials.
magneto-hydrodynamics, MHD චුම්බක-ජලවිදුලි විද්‍යාව A method of generating electricity by subjecting the free electrons in a high velocity flame or plasma to a strong magnetic field. The free electron concentration in the flame is increased by the thermal ionisation of added substances of low ionisation potential.
magnetomotive force, mmf චුම්බකගාමක බලය, චු ගා බ Magnetic potential required to drive the magnetic flux in the magnetic circuit. The magnitude of the mmf is equivalent to the product of the current through the turns and the number of turns of the coil.
magnetostriction චුම්බක කුංචනය A change in the dimensions of ferromagnetic substances on magnetisation.
main earthing terminal ප්‍රධාන පෘථිවි පර්යන්තය , ප්‍රධාන බිම් ගන්නන පර්යන්තය The terminal or bar provided for the connection of protective conductors, including equipotential bonding conductors, and conductors for functional earthing, if any, to the means of earthing.
main switch ප්‍රධාන ස්විච්චය A master switch that connects or disconnects the circuits in the electrical installation.
mains ජව මූලික Refers to the electricity supply from power stations to households or businesses and is supplied as alternating current (a.c.) of frequency 50 Hz.
maintenance factor නඩත්තු සාධකය Ratio of the average illuminance on the working plane after a specified period of use of a lighting installation to the average illuminance obtained under the same conditions for a new installation.
make/break contact සැදුම්/බිඳුම් ස්පර්ශකය These contacts have a stationary part and a moving part. By bringing the moving part to touch the stationary one, electric current flows and the breaker is closed. By driving the moving contact away from the stationary contact the electric arc develops and by quenching it the current stops flowing and the breaker is open.
malleability ආහන්‍යතාව Capacity of being hammered out into thin sheets.
manometer පීඩනමානය A manometer is a scientific instrument used to measure gas pressure.
manual transfer switch අතින් කරන මාරුව A switch designed so that it will disconnect the load from one power source and reconnect it to another source while at no time allowing both sources to be connected to the load simultaneously.
marginal cost ආන්තික පිරිවැය The sum that has to be paid for the next increment of product of service. The marginal cost of electricity is the price to be paid for kilowatt-hour above and beyond those supplied by presently available generating capacity irrespective of sunk costs.
market-based-price වෙළඳපල පදනම් මිල A price set by the mutual decisions of many buyers and sellers in a competitive market.
mass ස්කන්ධය A measure of the amount of matter in an object, usually measured in grams or kilograms.
matching transformer ගැළපන පරිණාමකය (ට්‍රාන්ස්ෆෝමරය) A device used to convert impedance between two levels. A common use is between a 75 ohm impedance and a 300 ohm impedance.
material ද්‍රව්‍යය, ද්‍රව්‍යයමය The matter from which a thing is or can be made.
matrix න්‍යාසය A matrix is a rectangular array of numbers for which operations such as addition and multiplication are defined.
matrix element න්‍යාස අවයවය Numbers that appear in the rows and columns of a matrix.
matrix equation න්‍යාස සමීකරණය An equation in which a variable is a matrix. Matrix equations can be solved by matrix manipulation.
matter පදාර්ථය It is any substance which has mass and occupies space.
maximum and minimum උපරිම සහ අවම The maximum and minimum of a function are the largest and smallest value that the function takes at a given point. Together they are known as the extrema.
maximum demand උපරිම ඉල්ලුම The largest of all demands of the load (usually expressed in kVA or MVA) that has occurred within a specified period of time.
Maxwell, Mx මැක්ස්වෙල් An old unit of magnetic flux. 1 Mx = 10-8 Wb
Maxwells equations මැක්ස්වෙල් සමීකරණ Maxwell's equations are a set of four differential equations that form the theoretical basis for describing classical electromagnetism.
mcb කුඩා පරිපථ කඩනය [see miniature circuit breaker]
mccb අච්චු කළ පරිපථ කඩනය [see moulded case circuit breaker]
mean මධ්‍යයනය The mean is the average of a set of numbers, or of a continuous variable.
mean square deviation මධ්‍යන්‍ය වර්ග අපගමනය Measure of the average of the squares of the difference between the estimated values and the actual value.
mean time between failure අසමත් වීම අතර මධ්‍යන්‍ය කාලය A statistical estimate of the time a component, subassembly, or operating unit will operate before failure will occur.
mebi (Mi) මෙබී Binary multiple prefix corresponding to megabinary or 220 or (210)2 or 10242. [IEC 1998]
mechanical breakdown යාන්ත්‍ර භංජනය Inability of a mechanical part to perform the function for which it was designed.
medical electrical equipment වෛද්‍ය විදුලි උපකරණ Electrical equipment, provided with no more than one connection to a particular supply mains, and intended to diagnose, treat or monitor the patient under medical supervision and which makes physical or electrical contact with the patient and/or transfers energy to or from the patient and/or detects such energy transfer to or from the patient. The equipment includes those accessories as defined by the manufacturer which are necessary to enable the normal use of the equipment.
mega (M) මෙගා Decimal multiple prefix corresponding to a million or 106.
megawatt (MW) මෙගාවොටය One million watts.
megawatt-hour (MWh) මෙගාවොට්-පැය One thousand kilowatt-hours or one million-watt hours.
Megger, megohmeter මෙගරය A high resistance range specially designed ohmmeter for measuring insulation resistance of conductors and other electrical equipment.
melting point ද්‍රවාංකය The constant temperature at which the solid and liquid phase of a substance are in equilibrium at a given pressure. The temperature at which a given solid will melt.
membrane පටලය A membrane is a selective barrier which allows some things to pass through but stops others.
mercury arc rectifier රසදිය චාප සෘජුකාරකය Original mercury arc rectifiers consisted of a glass tube with three or more electrodes. The cathode was a pool of mercury and the anodes were carbon rods, not touching the mercury but separated by a gap.
mercury barometer රසදිය වායුපීඩනමානය A barometer in which the weight of a column of mercury in a glass tube with a sealed top is balanced against that of the atmosphere pressing on an exposed cistern of mercury at the base of the mercury column, the height of the column varying with atmospheric pressure.
mercury thermometer රසදිය උෂ්ණත්වමානය Thermometer consisting of mercury contained in a bulb at the bottom of a graduated sealed glass capillary tube marked in degrees Celsius or Fahrenheit. With increase in temperature, the mercury expands causing a thin thread of mercury to rise in the tube.
mercury vapour lamp රසදිය වාෂ්ප පහන Lamp emitting a strong bluish-white light by the passage of an electric current through mercury vapour in a bulb.
mesh, loop දැලස, දැල A path through a circuit that starts and ends at the same place.
mesh analysis දැල් විශ්ලේෂණය A method of analysis of circuits based on defining mesh currents as the variables.
metal ලෝහය An element that readily forms positive ions and has metallic bonds. They conduct electricity and heat relatively well. Metals are typically malleable.
metal halide lamp ලෝහ හැලයිඩ් ලාම්පුව Discharge lamp in which the major portion of the light is produced by the radiation from a mixture of a metallic vapor (for example, mercury) and the products of the dissociation of halides (for example, halides of thallium, indium or sodium).
metal oxide semiconductor FET ලෝහ ඔක්සයිඩ් අර්ධ සන්නායක FET [see MOSFET]
metal oxide varistor, MOV ලෝහ ඔක්සයිඩ් විචලනය MOV is a voltage dependent, nonlinear device that is designed to protect various types of devices from switching and induced lightning voltage surges.
metal vapor lamp ලෝහ වාෂ්ප ලාම්පුව Discharge lamp such as the 'mercury (vapor) lamp' and the 'sodium (vapor) lamp' in which the light is mainly produced in a metallic vapor.
meter මානය, මීටරය Is an instrument to display or record only values that have been presented to it.
meter (m) මීටරය The meter is the SI unit of length. It is a fundamental unit. It is defined as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second [1983]
metering මැනීම Monitoring of energy or water consumption or other data over a period of time.
metre මීටරය The fundamental unit of length in the metric system, originally intended to be equal to one ten-millionth of the distance from the equator to the pole measured on a meridian. Now defined in terms of the velocity of light.
metre bridge මීටර සේතුව Also called a slide wire bridge, is an instrument that works on the principle of a Wheatstone bridge. Part of the meter bridge consists of a long slide wire of 1m length on which a slider is adjusted for balance.
metre kilogram second ampere system of units, M.K.S. system of units මීටර කිලෝග්‍රෑම් තත්පර ඇම්පියරය (මි.කි.ත) ඒකක ක්‍රමය A physical system of measurement that uses the metre, kilogram, and second as base units.
metric system මීටර ක්‍රමය The metric system is an internationally recognised decimalised system of measurement. The SI units are a sub-system of this.
mica තලාතු මිනිරන්, මයිකා Mica is a mineral name given to a group of minerals that are physically and chemically similar. They are all silicate minerals, known as sheet silicates because they form in distinct layers.
micro (m) මයික්‍රෝ Decimal sub-multiple prefix corresponding to one-millionth or 10-6.
microgrid මයික්‍රෝ ජාලකය A microgrid is a localized group of electricity sources and loads that normally operates connected to and synchronous with the traditional wide area synchronous grid, but can also disconnect to "island mode" — and function autonomously as physical or economic conditions dictate.
micrometer screw gauge මයික්‍රෝමීටර ඉස්කුරුප්පු ආමානය A device incorporating a calibrated screw widely used for accurate measurement of components such as the diameter of a thin wire or the thickness of a sheet of metal.
micron මයික්‍රෝනය A unit of length equal to one millionth of a metre, used in many technological and scientific fields.
microphone මයික්‍රෝපෝනය An instrument for converting sound waves into electrical energy variations which may then be amplified, transmitted, or recorded.
microphone ශබ්දවාහිනිය An electromechanical transducer that converts sound pressure into an electrical signal.
microprocessor ක්ෂුද්‍ර සකසනය (මයික්‍රොප්‍රොසෙසරය) A large scale integrated circuit that can be programmed to perform arithmetic and logic functions and to manipulate data.
microscope අණ්වීක්ෂය An optical instrument used for viewing very small objects, such as mineral samples or animal or plant cells, typically magnified several hundred times.
microscopic අණ්වීක්ෂීය So small as to be visible only with a microscope.
microwave සූක්ෂ්ම තරංග An electromagnetic wave with a frequency of 1 GHz or more, with a wavelength in the range 1-300mm, shorter than that of a normal radio wave but longer than those of infrared radiation.
microwave heating සූක්ෂ්ම තරංග තාපනය In the case of microwaves, the electric field is primarily responsible for generation of heat, interacting with molecules via two modes of action: dipolar rotation and ionic conduction. Microwaves instantly heat any solvent, solute, or material in solution through dipolar rotation and/or ionic conduction, resulting in a more efficient, more precise, and safer mode of heating.
microwave සූක්ෂ්ම තරංග Electromagnetic radiation with wavelengths ranging from very short radio waves to almost infra-red region. Wavelengths from 300 mm to 1 mm.
mil මිලය A unit of small length in the imperial system equal to one-thousandth of an inch. 1 mil = 2.54 x 10-5 m
mile සැතපුම Unit of distance in the imperial system. 1 mile = 1.609 km
miles per hour,  mph පැයට සැතැප්ම Unit of speed in the imperial system. 1 mph = 0.44704 m/s = 1.60934 km/h
milli (m) මිලි (දාභෙන් පංගුව) Decimal sub-multiple prefix corresponding to one-thousandth or 10-3.
mineral ඛනිජ A mineral is a naturally occurring inorganic solid, with a definite chemical composition, and an ordered atomic arrangement.
mineral oil ඛනිජ තෙල් General name given to the various mixtures of natural hydrocarbons.
miniature circuit breaker, mcb කුඩා පරිපථ කඩනය A device designed to perform the same function as a fuse but resettable. When the circuit breaker activates, or trips out, it disconnects the circuit. The fault condition must be found and rectified before the mcb can be reset. Usually for ratings less than 63 A.
mirror galvanometer දර්පණ ගැල්වනෝමීටරය A mirror galvanometer is an electromechanical instrument that indicates that it has sensed an electric current by deflecting a light beam with a mirror. The beam of light projected on a scale acts as a long massless pointer.
mks system මී කි ඒකක ක්‍රමය The metric system in which the meter, kilogram and the second are the fundamental units.
mobile සචල Able to move or be moved freely or easily.
mobile substation ජංගම උපපොළ A movable substation which is used when a substation is not working or additional power is needed.
mode විධිය A way or manner in which something occurs or is experienced, expressed, or done.
mode of propagation ප්‍රචාරණ විධිය The manner in which signals or gurges can travel from a transmitting end to the receiving end.
modem මොඩමය A hardware device that converts digital computer data into analog tones that can be transmitted over dial-up telephone circuits.
moderator උපපරිපාලක A substance used in nuclear reactors to reduce the speed of fast neutrons produced by nuclear fission.
modulator මූර්ඡකය The process of varying some characteristic of one wave (carrier wave) in accordance with some characteristic of another wave.
modulus මාපාංකය The absolute value of a real or complex number
moisture තෙතමන Water or other liquid diffused in a small quantity as vapour, within a solid, or condensed on a surface.
mole (mol) මෞල The mole is the SI unit of the amount of substance. It is defined as the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12; [1971]
molecule අණුව A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
moment ඝූර්ණය A moment is the turning effect of a force.
momentary overvoltage or swell තාවකාලික අධි වෝල්ටීයතාව හෝ ඉදිමීම An increase in voltage outside the normal tolerance for a few seconds or less. Voltage swells are often caused by sudden load decreases or turn-off of heavy equipment.
momentum ගම්‍යතාව The quantity of motion of a moving body, measured as a product of its mass and velocity.
monochromatic light ඒකවර්ණ ආලෝකය Monochromatic light is optical radiation containing only a single optical frequency. Light sources can also be called monochromatic, if they emit monochromatic light.
monochromatic radiation ඒකවර්ණ විකිරණය Radiation characterized by a single frequency. In practice, radiation of a very small range of frequencies that can be described by stating a single frequency.
monopole ඒකධ්‍රැවය A single electric charge or magnetic pole, especially a hypothetical isolated pole.
monopoly ඒකාධිකාරය The only seller with control over market sales.
mortality rate මර්ත්‍යතා අනුපාතිකය The number of operating hours elapsed before a certain percentage of the lamps fail.
MOSFET ලෝහ ඔක්සයිඩ් අර්ධ සන්නායක FET Metal oxide semiconductor FET often used in switching amplifier applications. This transistor provides extremely low power dissipation even with high currents.
motor generator set මෝටර් ජනක යන්ත්‍ර කට්ටලය A motor generator set consists of an ac motor coupled to a generator. The utility power energizes the motor to drive the generator, which powers the critical load. Motor generator sets provide protection against noise and spikes, and, if equipped with a heavy flywheel, they may also protect against sags and swells.
motor මෝටර් A rotating device which converts electrical power into mechanical power.
moulded case circuit breaker, mccb අච්චු කළ පරිපථ කඩනය A circuit breaker with a moulded case originally designed for currents exceeding 100 A.
MOV , metal oxide varistor ලෝහ ඔක්සයිඩ් විචලනය A solid state device which becomes conductive when the voltage across it exceeds a certain level. When the voltage exceeds the MOV's threshold, a heavy current flows through the MOV instead of the load.
moving coil galvanometer සල දඟර ගැල්වනෝමීටරය A galvanometer that is operated by the force exerted by an electric current flowing in a movable coil suspended in a magnetic field.
moving coil meter චලන දඟර මීටරය In this instrument, a moving coil is suspended between the poles of a permanent magnet. When a current is passed through the coil, the coil becomes an electromagnet and tries to align with the permanent magnet. The deflecting becomes proportional to the current.
moving iron meter චලන යකඩ මීටරය An instrument working on the principle of a moving iron placed within an electromagnet getting an induced emf and with the deflection being proportional to the square of the current. The meter is calibrated with the square root of the deflection and hence has basically a non-linear scale.
multiplex බහුකාර්ය To put information from several sources on to a single line or transmission path.
multiplier ගුණකය A quantity by which a given number (the multiplicand) is to be multiplied.
municipal electric utility නාගරික විදුලි උපයෝගීතාව A power utility system owned and operated by a local jurisdiction or local authority.
municipal solid waste නාගරික ඝණ අපද්‍රව්‍ A Biomass resource that can be used to produce energy by the process of incineration.
mutual inductance අන්‍යෝන්‍ය ප්‍රේරණතාව The coefficient of mutual induction, usually expressed in henries. The ability of one conductor to induce an emf in a nearby conductor when the current in the first conductor changes. It is the constant of proportionality between the induced voltage in the second inductor and the rate of change of current in the first inductor.
N මුලට TOP
NAND gate NAND ගේට්ටුව The logic gate that outputs a 0 only when all its inputs are 1s. It gives the complement of the AND gate.
nano (n) නැනෝ Decimal sub-multiple prefix corresponding to one-trillionth (US) or 10-9.
natural ස්වාභාවික Existing in or derived from nature. Not made or caused by humankind.
natural gas ස්වාභාවික වායු A naturally occurring mixture of hydrocarbon and non-hydrocarbon gases found in porous geological formations beneath the earth's surface, often in association with petroleum. The principal constituent is methane.
natural response ස්වාභාවික ප්‍රතිචාර The natural response of a circuit refers to be behaviour of the circuit (in terms of voltage and current), in the absence of external excitation.
NEC, national electrical code ජාතික විදුලි කේතය A set of rules and regulations that are put out by the National Fire protection Association. Generally accepted as the building wiring standard in the US.
needle කටුව, සූචිය, කූර A slender bar of steel, usually suspended on a low-friction mounting, and used in various instruments, to indicate the magnitude of a variable.
negative ඍණ A negative number is a real number which is less than zero.
negative feed back, negative feedback ඍණ ප්‍රතිපෝෂණය The return of part of an output signal to the input, which is completely out of phase with it, so that amplifier gain is reduced and the output is improved.
negative sequence සෘණ අනුක්‍රමය A balanced set of three phase components which have the same magnitude, opposite sequence to the original unbalanced set, and phase angle differing from each other by 120o. The frequency is of course the same as the original unbalanced three phase system.
negative terminal ඍණ අග්‍රය The terminal of a battery or other voltage source that has more electrons than normal. Electrons flow from the negative terminal through the external circuit to the positive terminal.
NEMA, National Electrical Manufacturers Association ජාතික විදුලි නිෂ්පාදකයින්ගේ සංගමය A non-profit trade association supported by the manufacturers of electrical apparatus and supplies in the US. NEMA promulgates standards to facilitate understanding between the manufacturers and users of electrical products.
neon lamp නියොන් ලාම්පුව Neon lamps are gas discharge lamps that contain neon gas at a low pressure, enveloped in a glass capsule. Neon lamps have been used widely in neon sign boards.
net capability ශුද්ධ හැකියාව Maximum load carrying ability of the equipment, excluding station use.
net generation ශුද්ධ උත්පාදනය Gross generation minus the energy consumed at the generating station for its use.
network synthesis ජාල සංස්ලේෂණය Finding a network that represents a given transfer function.
network ජාල A system of transmission and distribution lines cross-connected and operated to permit multiple power supply to any principal point on it.
neutral උදාසීන Neutral is a circuit conductor that normally carries current back to the source, and is connected to earth at the main electrical panel. The point common to all phases of a polyphase circuit, a conductor to that point, or the return conductor in a single phase circuit.
neutral conductor උදාසීන සන්නායකය A conductor connected to the neutral point of a system and contributing to the transmission of electrical energy. The term also means the equivalent conductor of an IT or d.c. system unless otherwise specified in the Regulations and also identifies either the mid wire of a three wire d.c. circuit or the earthed conductor of a two wire earthed d.c. circuit.
neutral point displacement voltage උදාසීන ලක්ෂ්‍ය විස්ථාපන වෝල්ටීයතාවය The voltage between the real or virtual neutral point and the earth.
newton (N) නිව්ටනය SI unit of force. One newton is equal to the force required to accelerate a body with the mass one kilogram by one metre per second per second.
nodal analysis නෝඩල් විශ්ලේෂණය A method of analysis of circuits based on defining node voltages as the variables.
node නිෂ්පන්දය, මංසල, සංදිය, නෝඩුව A node is any point on a circuit where the terminals of two or more circuit elements meet. In circuit diagrams, connections are ideal wires with zero resistance, so a node may consist of the entire section of wire between elements, not just a single point.
noise ඝෝෂාව, ශබ්දය Irregular fluctuations that accompany a transmitted electrical signal but are not part of it and tend to obscure it. An unwanted random signal (in the form of a voltage or current) in an electrical circuit making the information more difficult to identify.
noise level ඝෝෂා මට්ටම Noise level is the background sound pressure level at a given location, normally specified as a reference level.
nominal voltage නාමික වෝල්ටීයතාවය A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage rating. The actual voltage at which a circuit operates can vary from the nominal within a range that permits satisfactory operation of equipment. A suitable approximate value of voltage used to designate or identify a System.
non inductive අප්‍රේරක A non-inductive resistance is a resistance which has no inductance. A non-inductive resistor is wound one way then again in the other direction (bi-filar winding) to cancel any inductive effect.
non linear, non-linear නිරේජක, අරේඛීය, රේඛීය නොවන A nonlinear system is a system in which the change of the output is not directly proportional to the change of the input.
non uniform අනේකාකාර Used to describe something that is not the same in all places and situations.
non-coincidental peak load අහම්බෙන් නොවන උපරිම භාරය The sum of two or more peak loads on individual systems, not occurring in the same time period.
non-firm power ස්ථිර නොවන ජවය Power supplied or available under terms with limited or no assured availability.
non-inductive load ප්‍රේරක නොවන භාරය A non-inductive load is a load in which the current is in phase with the voltage across the load. (See Inductive Load)
non-utility generator උපයෝගිතා නොවන උත්පාදකය Independent power producers, exempt wholesale generators and other companies in the power generation business that have been exempted from traditional utility regulation.
non-utility power producer උපයෝගිතා නොවන බලශක්ති නිෂ්පාදකයා A legal entity that owns electric generating capacity, but it not an electric utility.
NOR gate NOR ගේට්ටුව A logic circuit that outputs a 1 only when each one of its inputs is a 0.
norm ප්‍රතිමානය Informal guideline about what is considered normal.
normal temperature and pressure, NTP සාමාන්‍ය උෂ්ණත්වය හා පීඩනය Normal temperature and pressure (NTP) is commonly used as a standard condition for testing and documentation in electrical industry. It commonly corresponds to 20oC and 760 torr.
normally open and normally closed සාමාන්‍යයෙන් විවෘතව ඇති, සාමාන්‍යයෙන් වසා ඇති The terms "Normally Open" and "Normally Closed" are applied to a magnetically operated switching device (such as a contactor or relay, or to the contacts thereof) to signify the position taken when the operating magnet is de-energized.
normal-mode noise සාමාන්‍ය මාදිලියේ ශබ්දය noise signal which appears between a set of phase conductors.
Norton's theorem නෝටන්ගේ ප්‍රමේය States that a linear two-terminal circuit can be replaced by an equivalent circuit consisting of an equivalent current source and a shunt equivalent admittance.
NOT circuit NOT පරිපථය A logic circuit that inverts its only input.
notation අංකනය A system of symbols used to represent special things.
NTP, Normal temperature and pressure condition සාමාන්‍ය උෂ්ණත්වය සහ පීඩනය Normal temperature may be taken as 0oC (physics) or 20oC (engineering) while normal pressure is taken as 760 torr.
nuclear energy න්යෂ්ටික ශක්තිය Energy produced in the form of heat during the fission process in a nuclear reactor. When released in sufficient and controlled quantity, this heat energy may be used to produce steam to drive a turbine-generator and thus be converted to electrical energy.
nuclear fission න්යෂ්ටික විඛණ්ඩනය A nuclear reaction in which a heavy atomic nucleus splits into two parts, and at the same time emitting neutrons and releasing very large amounts of nuclear energy.
nuclear fuel න්‍යෂ්ටික ඉන්ධන Fissionable materials that have been enriched to such a composition that, when placed in a nuclear reactor, will support a self-sustaining fission chain reaction, producing heat in a controlled manner for process use.
nuclear fusion න්‍යෂ්ටික විලයනය A nuclear reaction between light atomic nuclei as a result of which a heavier nucleus is formed and a large quantity of nuclear energy is released.
nuclear power plant න්‍යෂ්ටික බලාගාරය A facility in which heat produced in a reactor by the fissioning of nuclear fuel is used to drive a steam turbine.
nuclear power න්‍යෂ්ටික ජවය Power released in exothermic (a reaction which gives off heat) nuclear reactions which can be converted to electric power by means of heat transformation equipment and a turbine-generator unit.
nucleus න්‍යෂ්ටිය The positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass.
null method අභිශුන්‍ය ක්‍රමය A method of measurement in which an unknown quantity is compared with a known quantity of the same kind to yield a zero response of the detector.
numerical integration සංඛ්‍යාත්මක කලනය An approximate computation of an integral using numerical techniques.
NVD, neutral voltage displacement උදාසීන වෝල්ටීයතා විස්ථාපනය A technique to measure the displacement of the neutral voltage with respect to earth.
O මුලට TOP
obligation to serve සේවය කිරීමට බැඳීම The obligation of a utility to provide electric service to any consumer who seeks that service, and is willing to pay the rates set for that service. Traditionally, utilities have assumed the obligation to serve in return for an exclusive monopoly franchise.
observer නිරීක්ෂකයා A state observer is a system that provides an estimate of the internal state of a given real system, from measurements of the input and output of the real system.
obstacle බාධකය An obstacle is something, material or nonmaterial, that stands in the way of literal or figurative progress.
octal අෂ්ටක A group of 8 symbols from 0 to 7.
odd symmetry, odd function ඔත්තේ සමමිතිය හෝ ක්‍රියාකාරීත්වය A function has odd symmetry when its plot is anti-symmetrical about the vertical axis. f(t) = - f(-t)
oerstead (Oe) ඔඑස්ටෙඩය An old unit of magnetic field in the c.g.s. system. 1 Oe = 7.958 x 10-1 A/m
off-line UPS මාර්ග අපගත UPS An uninterruptible power supply (UPS) which feeds power to the load directly from the utility and then transfers to battery power via an inverter after utility drops below a specified voltage. The delay between utility power loss and inverter startup can be long enough to disrupt the operation of some sensitive loads.
off-peak කාර්යබහුල නොවන Periods of relatively low system demands.
ohm ඕමය SI unit of electric resistance. One ohm is equal to the electric resistance between two points of a conductor when a constant potential difference of 1 V, applied to these points, produces in the conductor a current of 1 A, the conductor not being the seat of any electromotive force.
ohmic heating ඕමික තාපනය Ohmic heating is an electroheating technique based on the passage of electrical current through a product having electrical resistance.
ohmic resistance ඕමික ප්‍රතිරෝධය A material's opposition to the flow of electric current and obeying Ohm's law.
ohmmeter ඕම්මානය An instrument that measures electrical resistance directly in ohm. Megohmmeters measure large values of resistance, such as in insulation.
Ohm's law ඕම්ගේ නියමය States that the voltage across a resistor is directly proportional to the current flowing through the resistance.
online UPS මාර්ගගත UPS A UPS in which the inverter is on during normal operating conditions supplying conditioned power to the load through an inverter or converter that constantly controls the AC output of the UPS regardless of the utility line input. In the event of a utility power failure, there is no delay or transfer time to backup power.
on-peak energy කාර්යබහුල ඉල්ලුමකදී සපයනු ලබන ශක්තිය Energy supplied during periods of relatively high system demand as specified by the supplier.
op amp, operational amplifier කර්මක වර්ධකය (ඇම්ප්ලිෆයර්) An electronic circuit element that behaves like a voltage-controlled voltage source. It is designed to perform mathematical operations of addition, subtraction, multiplication, division, differentiation and integration.
open circuit විවෘත පරිපථය Any circuit which is not complete, or the passage of current interrupted, is considered an open circuit.
operating point කාරක ලක්ෂ්‍යය The operating point is a specific point within the operation characteristic of a technical device.
operating temperature කාරක උෂ්ණත්වය The range of temperature over which a device may be safely used. The temperature range which the device has been designed to operate.
operating voltage කාරක වෝල්ටීයතාවය The value of the voltage under normal conditions at a given instant and at a given point in the system.
operation and maintenance expenses, O & M , O and M මෙහෙයුම් සහ නඩත්තු වියදම් Costs that relate to the normal operating, maintenance and administrative activities of a business.
operational amplifier කර්මක වර්ධකය [see op amp]
operator ක්‍රියාකරු person handling equipment.
optical ප්‍රකාශ Refers to anything that relates to light, both visible light and infrared light, that performs a specific function.
optical radiation දෘශ්‍ය විකිරණ Electromagnetic radiation at wavelengths between the region of transition to Xrays (l » 1 nm) and the region of transition to radio waves (l » 1 mm).
optimum ප්‍රශස්තය The most favourable situation or level for growth, reproduction, or success.
options විකල්ප Options are potential decisions over which a utility has a reasonable degree of control.
optocoupler ඔප්ටෝ කප්ලර් A combination of an LED and a photodiode to give high isolation between the input and the output.
optoelectronics ඔප්ටෝ ඉලෙක්ට්‍රොනික්ස් A technology that combines optics and electronics, including many devices based on the action of a pn junction. Examples are LEDs, photodiodes, and optocouplers.
OR gate OR ගේට්ටුව A logic circuit that outputs a HIGH whenever one of its inputs is a HIGH.
orbit කක්ෂය The curved path of a celestial object or spacecraft round a star, planet, or moon, especially a periodic elliptical revolution.
order ගණය The arrangement things in relation to each other according to a particular sequence, pattern, or method.
origin ප්‍රභවය, මූල ලක්ෂ්‍යය Something from which anything arises or is derived.
origin of an installation ස්ථාපනයක ආරම්භය The position at which electrical energy is delivered to an electrical installation.
orthogonal ප්‍රලම්බ Of or involving right angles.
oscillating දෝලන Vary in magnitude or position in a regular manner about a central point.
oscillator දෝලකය A device for generating oscillatory electric currents or voltages by non-mechanical means.
oscilloscope ද්‍යෝලනේක්ෂය An instrument for making visible the instantaneous values of one or more rapidly varying electrical quantities as a function of time or of another electrical or mechanical quantity.
outage ඇනහිටීම් The period during which a generating unit, transmission line, or other facility is out of service.
outlet බිහිදොර, පිටවාන, පිටමුව An electrical outlet or receptacle is a socket that connects an electrical device to an electricity supply. A point on the wiring system at which current is taken to supply utilization equipment.
output ප්‍රතිදානය A place where power or information leaves a system.
overcurrent detection අධි ධාරා හඳුනාගැනීම A method of establishing that the value of current in a circuit exceeds a predetermined value for a specified length of time.
overcurrent අධි ධාරා Any current in excess of the rated current of equipment or the ampacity of a conductor. It may result from overload, short circuit, or ground fault.
overdamped අධිපරිමන්දිත The system returns to equilibrium without oscillating.
overhead උඩිස් Above the level of the head; in the sky.
overlapping අතිච්ඡාදනය Having some parts that are the same or happen at the same time.
overload current අධි භාර ධාරාව An overcurrent occurring in a circuit which is electrically sound.
overload protection අධි භාර ආරක්ෂණය Effect of a device operating on excessive current, but not necessarily on short circuit, to cause and maintain the interruption of current flow to the device being managed.
overload relay අධි භාර පිළියවනය (රිලේ ) A relay that responds to electric load and operates at a pre-set value of overload.
overload අධික භාර Over-loading occurs when extra power is taken from the supply. The increased current due to over-loading will have an immediate effect on the cables; they will begin to heat up. If the over-loading is sustained the result could be an accelerated deterioration of the cable insulation and its eventual breakdown to cause an electrical fault.
overloading අධිහරණය To put too great a demand on an electrical system.
overvoltage අධි වෝල්ටීයතාව A voltage that exceeds the maximum value of operating voltage. Similar to a surge but for a longer period of time, over 2.5 second.
P මුලට TOP
panel board, panelboard, distribution board පනේල පුවරුව A component of an electricity supply system that divides an electrical power feed into subsidiary circuits, while providing individual protection for each circuit in a common enclosure.
paper කඩදාසි Normally consists of sheets of cellulose, mainly obtained from wood pulp from which lignin and other non-cellulosic materials have been removed.
parabolic පරාවලියක In the shape of a part of a parabola
parallax අසම්පාතය Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines.
parallax error අසම්පාත දෝෂය An error in reading an instrument due to the eye of the observer and pointer not being in a line perpendicular to the plane of the scale.
parallel සමාන්තර Side by side and having the same distance continuously between them. Thus parallel lines never meet other than at infinity.
parallel (circuit) සමාන්තර Two or more elements are connected in parallel if they are connected to the same pair of nodes. parallel elements have the same voltage across them.
parallel resonance සමාන්තර අනුනාදය A resonance condition usually occurring in parallel RLC circuits, where the voltage becomes a maximum for a given current.
parity bit සමතා බිට් An additional bit that is attached to each code group so that the total number of 1s being transmitted is either odd or even.
partial discharge ආංශික විසර්ජනය, අර්ධ විසර්ජනය A localized dielectric breakdown, which does not completely bridge the space between the two conductors, of a small portion of a solid or liquid electrical insulation under high voltage stress. Discharges which are partial and are not flash overs across electrodes.
partition විභේදනය, විභාජකය, විභාග A structure dividing a space into two parts.
pascal (pa) පැස්කල් SI unit of pressure. One pascal is equal to the force of one newton exerted on one square meter.
passive element අකර්මන්‍ය අවයවය, උදාසීන අංගය An electrical component that does not generate power, but instead dissipates, stores, and/or releases it. Passive elements include resistances, capacitors, and inductors.
payback period ආපසු ගෙවීමේ කාලය The length of time it takes for the savings received to cover the cost of implementing the technology.
peak උපරිම, උච්ච Maximum value of an alternating or other waveform.
peak clipping මුදුන කප්පාදුව Peak clipping is used to reduce a utility's system peak, reducing the need to operate peaking units with relatively high fuel costs. Peak clipping is pursued only when the resources are not expected to be able to meet the impending load requirements.
peak day උපරිම දිනය The day of highest customer demand for electricity during a year.
peak demand උපරිම ඉල්ලුම The maximum load during a specified period of time.
peak factor උපරිම සාධකය Ratio of the peak value to the r.m.s. value of an alternating waveform.
peak inverse voltage උච්ච ප්‍රතිලෝම වෝල්ටීයතාව Is the maximum voltage a diode or other device can withstand in the reverse-biased direction before breakdown.
peak load උච්ච භාරය Peak load is the highest amount of energy that a consumer draws from the grid in a set period of time.
peak shaving උපරිම ඉල්ලුම අඩු කිරීම Techniques used by electric utilities to lower the peak demand on the system.
peak to peak amplitude උච්චයක සිට උච්චයක විස්තාරය The change occuring from a negative peak to a positive peak.
peak value උච්ච අගය The highest or maximum value of an alternation of alternating current or voltage. This peak value occurs twice during each cycle.
peak time උපරිම කාලය Period of relatively high system demand.
peaking capacity උපරිම ධාරිතාව Capacity of generating plants normally reserved for operation during the hours of highest daily, weekly, or seasonal loads. This equipment is usually designed to meet the portion of load that is above base load.
peaking plants උපරිම ඉල්ලුම කාලය තුළ ක්‍රියාත්මක වන බලාගාර Power plants that operate for a relatively small number of hours, usually during peak demand periods. Such plants usually have high operating costs and low capital costs.
peak-to-peak value උච්චයක සිට උච්චයක අගය The maximum voltage change occurring during one cycle of alternating voltage or current. The total amount of voltage between the positive peak and the negative peak of one cycle or twice the peak value.
pebi(pi) පෙබි Binary multiple prefix corresponding to petabinary or 250 or (210)5 or 10245. [IEC 1998]
Pelton wheel පෙල්ටන් රෝදය An impulse-type water turbine which extracts energy from the impulse of moving water.
PEN conductor PEN සන්නායකය A conductor combining the functions of both protective conductor and neutral conductor.
pendulum අවලම්බය A bob hung from a stationary point such that it can swing freely back and forth. A simple pendulum is one where the bob is treated as a point mass, and the string from which it hangs is of negligible mass and undergoes simple harmonic motion.
per unit, pu ඒකකයකට Per unit is a method of expressing the value of a quantity in terms of a reference or base quantity. It is very similar to percentage, except that there is no multiplying constant of 100.
percentage ප්‍රතිශතය A portion of a whole expressed as a number between 0 and 100 rather than as a fraction.
percentage error ප්‍රතිශත දෝෂය Difference between an experimental and theoretical value, divided by the theoretical value, multiplied by 100.
performance කරණය, කාර්ය ඵලය The accomplishment of a given task measured against preset known standard conditions such as accuracy.
performance attributes කාර්ය සාධන ලක්ෂණ Performance attributes measure the quality of service and operating efficiency. Loss of load probability, expected energy curtailment, and reserve margin are some of the performance attributes.
period කාලච්ඡේදය Duration between repetitions of a waveform cycle. It is also equal to the inverse of frequency).
periodic ආවර්තක, කාලාවර්තය Recurring at regular intervals.
periodic function ආවර්තිතා ශ්‍රිතය A function which repeats itself after a definite period.
permanent නිත්‍ය, ස්ථිර Lasting or intended to last or remain unchanged indefinitely.
permanent magnet නිත්‍ය චුම්බකය A magnet that retains its magnetic properties in the absence of an inducing field or current.
permanent magnet moving coil meter, pmmc ස්ථිර චුම්බක චලනය වන දඟර මීටරය [see moving coil meter]
permeability පාරගම්‍යතාව A quantity measuring the influence of a substance on the magnetic flux in the region it occupies. It is the constant in the proportionality between magnetic flux density and magnetic field intensity.
permeability of free space නිදහස් අවකාශයේ පාරගම්යතාව eo = 8.854 x 10-12 F/m
permeance පාරගමනය Inverse of reluctance [Unit: H]
permittivity පාරවේද්‍යතාව The ability of a substance to store electrical energy in an electric field. It is the constant of proportionality between electric displacement and electric field intensity. The permittivity of a material is defined as the constant of proportionality between the electric flux density and the electric field. It is a constant for a given dielectric.
permittivity of free space නිදහස් අවකාශයේ පාරවේද්‍යතාව µo = 4π x 10-7 H/m
peta (P) පෙටා Decimal multiple prefix corresponding to 1015.
petroleum, crude oil ඛණිජ තෙල් A naturally occurring, oily, flammable liquid composed principally of hydrocarbons. Crude oil is occasionally found in springs or pools but usually is drilled from wells beneath the earth's surface. A mixture of hydrocarbons existing in the liquid state found in natural underground reservoirs often associated with gas. petroleum includes crude oil, fuel oil, kerosene and jet fuel.
phase conductor අදියර සන්නායකය A conductor of an a.c. system for the transmission of electrical energy other than a neutral conductor, a protective conductor or a PEN conductor. The term also means the equivalent conductor of a d.c. system unless otherwise specified in the Regulations.
phase difference කලා අන්තරය Difference in phase angle between two sinusoids or phasors.
phase modulation අදියර මොඩියුලේෂන් Modulation of the phase angle of a sinusoidal carrier by an amount proportional to the instantaneous value of the modulating wave.
phase sequence, phase rotation අදියර අනුක්‍රමය, අදියර භ්‍රමණය The time order in which the voltages (or currents) pass through their respective maximum values (or any other definable position).
phase voltage අදියර වෝල්ටීයතාවය The voltage between the phase and neutral of a three phase system is defined as the phase-to-neutral voltage or more commonly as the phase voltage. For a balanced three phase system, the phase voltage is 1/S3 times the line-to-line voltage. The voltage across one arm of either a star-connected load or a delta-connected load is also sometimes referred to as the voltage across a phase or phase voltage. This latter quantity is the same as the phase-to-neutral voltage for a star-connected load, and the line-to-line voltage for a delta-connected load.
phase, phase angle කලාව, කලා කෝණය The phase of a waveform is the angle between the first zero-crossing and the point in space defined as the origin.
phasor diagram අවධික සටහන A diagram representing alternating current and voltage of the same frequency as phasors with the phase angle between them. Phasors are the arrows rotating in the anti-clockwise direction.
phasor අවධිකය Representation of a sinusoid on the Argand diagram in the form of the magnitude (usually r.m.s.) and phase angle. It may be represented as a complex number in either cartesian co-ordinates or polar co-ordinates.
phone බණුව A device that uses either a system of wires along which electrical signals are sent or a system of wireless signals to make it possible for you to speak to someone in another place who has a similar device
phonograph ශබ්දවාහිනිය An early form of gramophone using cylinders and able to record as well as reproduce sound.
phosphor ෆොස්ෆර් A substance which is capable of luminescence. That is storing energy and later releasing it in the form of light.
photocell, photo-electric cell පකාශ කෝෂය, ඡායා විද්‍යුත් කෝෂය Device used for the detection and measurement of light.
photoconductivity ප්‍රකාශ සන්නායකතාව Increased electrical conductivity caused by the presence of light.
photodiode ප්‍රකාශ දියෝඩය A reverse biased diode that is sensitive to incoming light.
photoelectric ප්‍රකාශ විද්‍යුත් Characterized by or involving the emission of electrons from a surface by the action of light.
photoionization ප්‍රකාශ අයනීකරණය Ionization produced in a medium by the action of electromagnetic radiation.
photon පෝටෝනය A particle representing a quantum of light or other electromagnetic radiation. A photon carries energy proportional to the radiation frequency but has zero rest mass and energy equal to the product of the frequency of radiation and planck's constant.
photovoltaic effect ප්‍රකාශ වෝල්ටීය ආචරණය A process that generates electricity in a photovoltaic cell when it is exposed to sunlight.  For example, photovoltaic cells transform light directly into electricity. Direct conversion systems have no moving parts and usually produce direct current.
photovoltaic ප්‍රකාශ වෝල්ටීයතාව A technology that directly converts light into electricity. The process uses modules, which are usually made up of many cells (thin layers of semiconductors).
physical භෞතික A property of a material or system that can be quantified by measurement.
pico (p) පිකෝ Decimal sub-multiple prefix corresponding to one trillionth (US) or 10-12.
PID සමානුපාතික, සමෝධානික සහ ව්‍යුත්පන්න A three mode control consisting of time Proportioning, Integral and Derivative rate action.
piecewise continuous waveforms කෑලි-අඛණ්ඩ තරංග Waveforms which are essentially continuous but in which multi-values occur over finite bounds. The waveform is single-valued and continuous in pieces.
piezo electric effect පීඩවිද්‍යුත් ආචරණය Vibrtion that occurs when a crystal is excited by an ac signal across its plates.
piezoelectric crystal පීඩවිද්‍යුත් ස්ඵටිකය Whenever piezoelectric crystals are mechanically deformed or subject to vibration they generate a small voltage, commonly know as piezoelectricity.
pilot program මඟ පෙන්වන වැඩසටහන A utility program offering a limited group of consumers their choice of certified or licensed energy suppliers on a one year minimum trial basis.
pin hole සුචි සිදුර A very small hole. A pore-like penetration that maybe present in coatings due to the entrapment of moisture, air or other fluids.
pipe line නළ මඟ A long pipe, typically underground, for conveying oil, gas, cables etc. over long distances.
pivot විවර්තනිය, විවටුව A short shaft or pin supporting something that turns. The hands of a large clock are usually supported on pivots.
Planck's constant h ප්ලාංක් නියතය Relates the energy in a photon of electromagnetic radiation to the frequency of that radiation. h = 6.6262x10-34 Js = 4.1357x10-15 eVs, Planck's constant (h/2p) = 1.05459x10-34 Js
plane තලය, තල A flat surface on which a straight line joining any two points on it would wholly lie.
planned generator සැලසුම්කළ ජනකය Proposal to install generating equipment at an existing or planned facility or site.
Plant යන්ත්‍රෝපකරණ A facility containing prime movers, electric generators, and other equipment for producing electric energy.
plasma ප්ලාස්මය An ionized gas containing about equal numbers of positive and negative charges, which is a good conductor of electricity, and is affected by a magnetic field.
plug පේනුව, ප්ලග් A device, provided with contact pins, which is intended to be attached to a flexible cable, and which can be engaged with a socket outlet or with a connector. The movable connector attached to an electrically operated device, and the socket is fixed and connected to an energised electrical circuit. The plug is a male connector with protruding pins that match the openings and female contacts in a socket.
pN junction pN සන්දිය A junction between an N-type semiconductor and a p-type semiconductor made by some method of diffusing, fusing or melting.
point ලක්ෂ්‍යය It indicates a location with zero size. It has no width, no length and no depth. A point is usually shown by a dot.
point (in wiring) ලක්ෂ්‍යය (රැහැන්වල) A termination of the fixed wiring intended for the connection of current using equipment.
point charge ලක්ෂ්‍යාකාර ආරෝපණය An electric charge regarded as concentrated at a point, without spatial extent.
point of common coupling, PCC පොදු සම්බන්ධතාවයේ ලක්ෂ්‍යය Power supplier-consumer metering point at which power is supplied to the electrical equipment of the consumer. The location of the connection between the CEB network and the Embedded Generator, beyond which other customer loads may be connected on the CEB side. The PCC may be separate from the Point of Supply where a line is dedicated to the connection of an Embedded Generator.
point of delivery භාරදීමේ ස්ථානය Point for interconnection on the Transmission Provider's System where capacity and/or energy are made available to the end user.
point of supply, POS සැපයුම් ස්ථානය The location of the connection between the CEB network and the Embedded Generator.
polar ධ්‍රැවක Having electrical or magnetic polarity.
polar coordinates, polar co-ordinates ධ්‍රැවක ඛණ්ඩාංක A two-dimensional coordinate system in which each point on a plane is determined by a distance from an origin (reference point) and an angle from a reference direction.
polar diagram ධ්‍රැවීය ප්‍රස්තාරය A diagram employing polar coordinates to show the magnitude of a quantity in some or all directions from a point.
polarisation ධ්‍රැවණය, වීකරණය Polarization occurs when an electric field distorts the negative cloud of electrons around positive atomic nuclei in a direction opposite the field.
polarity ධ්‍රැවීයතාව The property of having poles or being polar. Magnetically, opposite poles, north and south. In electricity, oppositely charged poles, positive and negative.
pole pieces ධ්‍රැව හිස් A mass of iron forming the end of an electromagnet, through which the lines of magnetic force are concentrated and directed.
polygon of forces බල බහුඅස්රය If the forces acting on an object can be represented by the sides of a polygon taken in order, the forces will be in equilibrium.
polyphase බහුකලා A general term applied to any system of more than a single phase. This term is ordinarily applied to symmetrical systems.
polythene පොලිතින් Tough thermoplastic material, made by the polymerisation of ethylene. It is flexible, transparent, chemically resistance and a good electrical insulator.
polyvinyl chloride, PVC පොලිවිනිල් ක්ලෝරයිඩ් A synthetic transparent thermoplastic material made by polymerizing vinyl chloride.
porcelain පෝසිලේන් Hard, white material made by the firing of a mixture of pure kaolin (china clay) with felspar and quartz, or with other materials containing silica.
porosity සවිවරතාව A measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0 and 1.
port තොට A pair of terminals through which a single current may enter or leave a network.
portable equipment අතේ ගෙන යාහැකි උපකරණ Electrical equipment which is moved while in operation or which can easily be moved from one place to another while connected to the supply.
positive ධන Numbers that are greater than zero.
positive feedback ධනාත්මක ප්‍රතිපෝෂණය Feedback where the returning signal aids the effect of the input signal.
positive ion ධන අයනය An electrically charged atom or group of atoms formed by the loss or gain of one or more electrons.
positive sequence ධනාත්මක අනුක්‍රමය A balanced set of three phase components which have the same magnitude, same sequence as the original unbalanced set, and phase angle diferring from each other by 120o. The frequency is of course the same as the original unbalanced three phase system.
potential විභවය Electric potential at a point is defined as the amount of work done in moving a unit positive charge from infinity to that point.
potential difference විභව අන්තරය The difference of electrical potential between two points. The work done in moving a unit positive electric charge from one point to another. [Unit: volt or V]
potential divider විභව බෙදුම්කරු A combination of impedances which allows a fraction of the input voltage to be taken as output.
potential energy විභව ශක්තිය Energy which a body possesses by virtue of its position. The potential energy of water in a reservoir is usually measured with respect to sea level.
potential equalization conductor විභව සමීකරණ සන්නායකය Conductor providing a connection between equipment and the potential equalization busbar of the electrical installation.
potential transformer විභව පරිණාමකය (ට්‍රාන්ස්ෆෝමර්) An instrument transformer specifically designed to give an accurate voltage ratio for measurement and/or control purposes. They are always connected in parallel with the circuit (like a voltmeter).
potentiometer විභවමානය A three terminal device with a wiper that is positioned along a resistive element, making it a voltage divider. A piece of apparatus by means of which emfs are compared using null deflection.
pound lb රාත්තල The imperial unit of weight. 1 lb = 0.453,592 kg
poundal පවුන්ඩලය The imperial unit of force. It is that force which acting on a mass of 1 lb will impart to it an acceleration of 1 ft/s2.
power ජවය,බලය The amount of energy produced in a unit amount of time.
power conditioning systems ජවයඅනුකුලීකරණය A broad class of equipment that includes filters, isolation transformers, and voltage regulators. Generally, these types of equipment offer no protection against power outages.
power dissipation ජවයඋත්සර්ජනය The amount of power that is consumed and converted to heat.
power distribution unit බල බෙදාහැරීමේ ඒකකය A portable electrical distribution unit that provides an easily expandable and flexible electrical environment for an equipment and its associated peripherals.
power exchange බල හුවමාරුව This is a commercial entity responsible for facilitating the development of transparent spot prices for energy capacity, and/or ancillary services.
power factor correction capacitor බල සාධකය නිවැරදි කිරීමේ ධාරිත්‍රකය This is a device that helps improve the efficiency of the flow of electricity through distribution lines by reducing energy losses. It is installed in substations and on poles. Usually it is installed to correct an unwanted condition in an electrical system.
power factor correction බල සාධකය නිවැරදි කිරීම Process of increasing the power factor to near unity without altering the original load.
power factor, PF බල සාධකය Ratio of the active power consumed by a component or circuit to the apparent power. For purely sinusoidal waveforms, this is also equal to the cosine of the phase angle between the voltage and the current.
power grid, National Grid විදුලිබල ජාලය (ජාතික ජාලකය) A network of power lines and associated equipment used to transmit and distribute electricity over a geographic area (or country).
power house විදුලි පොළ, ජව පොළ A building that produces electrical power.
power marketers බලශක්ති අලෙවිකරුවන් Entities engaged in buying and selling electricity.
power plant බලාගාරය A generating station where electricity is produced.
power pool බල සංචිතය An association of two or more interconnected electric systems having an agreement to coordinate operations and planning for improved reliability and efficiencies.
power purchase agreement, PPA ජවයමිලදී ගැනීමේ ගිවිසුම A contract entered into by an independent power producer and an electric utility. The power purchase agreement specifies the terms and conditions under which electric power will be generated and purchased. Power purchase agreements generally include: specification of the size and operating parameters of the generation facility; contract terms; price mechanisms; service and performance obligations; dispatchability options; and conditions of termination or default.
power supply ජව සැපයුම, බල සැපයුම An electrical device that supplies electric power to an electrical load. The part of a circuit that supplies power to the entire circuit or part of the circuit.
power system බල පද්ධතිය A network of electrical components deployed to supply, transfer, and use electric power.
power transformer ජව පරිණාමකය A static apparatus with two or more windings which, by electromagnetic induction, transforms a system of alternating voltage and current into another system of voltage and current.
power ජවය​ (බලය) The time rate of consuming or absorbing energy. The active component of power in an alternating circuit is usually referred to as power or active power. [Unit: watt or W]
precision යාථාතථ්‍, නියතාර්ථය The degree to which several measurements provide answers very close to each other.
prediction පුරෝකථනය A prediction is a guess what might happen based on observation and sometimes evidence.
present value වර්තමාන වටිනාකම The amount of money required to secure a specified cash flow on a future date at a given rate of return.
present worth factor වර්තමාන වටිනා සාධකය The adjustment factor that discounts a sum of future dollars back to the current year.
pressure පීඩනය A measure of the force applied over unit area.
price cap මිල සීමාව Situation where a price has been determined and fixed.
primary circuit ප්‍රාථමික පරිපථය Distribution circuit (less than 69,000 volts) on the high voltage side of the transformer.
primary winding ප්‍රාථමික වෙළුම The winding of a transformer that is connected to and receives energy from an external source.
primary ප්‍රාථමික That winding of a transformer which is connected to and receives energy from an external source of electrons.
prime mover ප්රාථමික චාලකය The engine, turbine, water wheel, or similar machine that drives an electric generator; or, for reporting purposes, a device that converts energy to electricity directly (e.g., photovoltaic solar and fuel cells).
principle of duality ද්වෛත මූලධර්මය A dual of a relationship may be formed by interchanging variables of two systems.
printed circuit මුද්‍රිත පරිපථය A method of manufacturing parts of electronic equipment in which the wiring between components, and certain fixed components themselves, are printed on to an insulating board.
prism ප්‍රිස්මය A transparent solid body, often having triangular bases, used for dispersing light into a spectrum rays of light.
probability සම්භාවිතාව The extent to which an event is likely to occur, measured by the ratio of the favourable cases to the total number of cases possible.
probe ඒෂණිය An oscilloscope input device, usually having a pointed metal tip for making electrical contact with a circuit element and a flexible cable for transmitting the signal to the oscilloscope.
production costing නිෂ්පාදන පිරිවැය A method used to determine the most economical way to operate a given system of power resources under given load conditions.
production නිෂ්පාදනය The act or process of generating electric energy.
profile පැතිකඩ A brief description of the characteristics of something.
project financing ව්‍යාපෘති මූල්‍යකරණය Most commonly used method to finance the construction of independent power facilities. Typically, the developer pledges the value of the plant and part or all of its expected revenues as collateral to secure financing from private lenders.
pROM0 වැඩසටහන්ගත කළ හැකි කියවීමට පමණක් මතකය A ROM that can be programmed by the user. It cannot be reprogrammed.
propagation constant ප්‍රචාරණ නියතය The propagation constant of a sinusoidal electromagnetic wave is a measure of the change undergone by the amplitude and phase of the wave as it propagates in a given direction.
propagation ප්‍රචාරණය The movement or spread of a wave or surge in some direction or through a medium.
proportion සමානුපාතය A part, share, or number considered in comparative relation to a whole
prorated bills අනුමත බිල්පත් The computation of a bill based upon proportionate distribution of the applicable billing schedule.
prospective fault current අනාගත දෝෂ ධාරාව The value of overcurrent at a given point in a circuit resulting from a fault of negligible impedance between live conductors having a difference of potential under normal operating conditions, or between a live conductor and an exposed conductive part.
protective coating ආරක්ෂක ආලේපය A layer of material applied to the surface of another material with the intent of inhibiting or preventing a destrutive effect such as corrosion or flashover.
protective conductor current ආරක්ෂිත සන්නායක ධාරාව Electric current which flows in a prospective conductor under normal operating conditions:
protective conductor ආරක්ෂිත සන්නායකය Conductor used for some measures of protection against electric shock and intended for connecting together any of the following parts:
protective earth conductor ආරක්ෂිත බිම් ගන්නන සන්නායකය Conductor to be connected between the protective earth terminal and an external protective earthing system.
protective earth terminal ආරක්ෂිත බිම් ගන්නන පර්යන්තය Terminal connected to conductive parts of Class I equipment for safety purposes. This terminal is intended to be connected to an external earthing system by a protective earth conductor.
protective extra low voltage, PELV අතිරේක අඩු වෝල්ටීයතාවයක් An extra low voltage system which is not electrically separated from earth, but which otherwise satisfies all the requirements for SELV.
protective multiple earthing, PME ආරක්ෂිත බහු බිම් ගන්න An earthing arrangement, found in TN C S systems, in which the supply neutral conductor is used to connect the earthing conductor of an installation with Earth, in accordance with the Electricity Safety, Quality and Continuity Regulations 2002.
proximity sensor or proximity switch සමීපතා සංවේදකය හෝ සමීපතා ස්විචය A sensor or switch with the ability to detect it's relationship to a metal target without making physical contact.
psi lb/in2 වර්ග අඟලකට රාත්තල් Unit of pressure in the imperial system.1 psi = 6895 pa
public utility commission මහජන උපයෝගිතා කොමිෂන් සභාව State regulatory agencies that provide oversight, policy guidelines and direction to public utilities including electricity.
public utility මහජන උපයෝගීතාව A utility operated by a non-profit governmental or quasi-governmental entity. Public utilities include municipal utilities, cooperatives, and power marketing authorities.
publicly owned utilities පොදු සතු උපයෝගිතා Municipal utilities (utilities owned by branches of local government) and/or co-operatives (utilities owned cooperatively by consumers).
pulse ස්පන්දය A single short burst electric current or other wave.
pulse width modulation, PWM ස්පන්දන පළල මූර්ඡනය Control of the width of pulses for the purpose of information transmission.
pumped storage hydroelectric plant පොම්ප ගබඩා ජල විදුලි බලාගාරය A plant that usually generates electric energy during peak-load periods by using water previously pumped into an elevated storage reservoir during off-peak periods when excess generating capacity is available.
pumped storage පොම්ප කළ ගබඩාව A facility designed to generate electric power during peak load periods with a hydroelectric plant using water pumped into a storage reservoir during off-peak periods.
puncture ඡිද්‍රකය A permanent failure caused by the breakdown of insulation.
purchased power adjustment මිලදී ගත් බල ගැලපුම A clause in a rate schedule that provides for adjustments to a bill when energy from another system is acquired.
pure ශුද්ධ, සංශුද්ධ Not mixed or adulterated with any other substance or material.
pushbutton ඔබන බොත්තම Part of an electrical device, consisting of a button that must be pressed to effect an operation.
Q මුලට TOP
Q factor, quality factor Q සාධකය, ගුණ සාධකය Relates the maximum energy stored in the circuit to the energy dissipated during a cycle of the waveform.
Q meter Q මානය An older piece of equipment used in the testing of radio frequency circuits.
quadrant electrometer පාදක විද්‍යුත්මානය An electrostatic meter for measuring small potential differences. It consists of an electrometer in the form of a broad, shallow metal cylinder composed of four mutually insulated quadrants, within which there is a suspended vane which turns when a voltage is applied to some of the quadrants when the others are earthed.
quadrant ක්වන්ද්‍රාන්තුව Quarter circle. Sector of a circle bounded by an arc and two radii at right angles.
quadratic equation වර්ග සමීකරණය A second order algebraic equation containing a squared term and lesser order terms of the form ax2 + bx + C = 0. It has two roots which satisfy the equation.
quadrature ඍජුකෝණියතාව වර්ගාමාතිය Two quantities which are at right angle to each other. A quadrature component of a wave is 90° out of phase with the main or in-phase component.
qualitative ගුණාත්මක Relating to the measurement or expression of the quality of something rather than its quantity.
quality control තත්ත්ව පාලනය Inspection, analysis and action required to ensure quality of output.
quality factor Q ගුණාත්මක සාධකය, ගුණ සාධකය The quality factor of a resonant circuit is the ratio of its resonant frequency to its bandwidth. The higher the quality factor, the lower the losses in the circuit and higher the resonant peak.
quantisation ක්වොන්ටීකරණය The process of converting a continuous range of values into a finite range of discrete values.
quantisation error ප්‍රමාණකරණ දෝෂය The error caused by non-zero resolution of an analog to digital converter. It is an inherent error of the device.
quantitative ප්‍රමාණාත්මක Relating to the measurement of expression of a quantity by giving a numerical value.
quantum electronics ක්වොන්ටම් ඉලෙක්ට්‍රොනික Applying molecular physics to electronics.
quantum mechanics ක්වොන්ටම් යාන්ත්‍ර විද්‍යාව The branch of mechanics that deals with the mathematical description of the motion and interaction of subatomic particles, incorporating the concepts of quantization of energy, wave–particle duality, the uncertainty principle, and the correspondence principle.
quantum ක්වොන්ටම් One of the very small discrete packets into which many forms of energy are subdivided.
quark මූලික අංශුවක කොටස (ක්වාර්ක්) Any subatomic particle carrying a fractional electric charge, postulated as building blocks of the hadrons. Quarks have not been directly observed but theoretical predictions based on their existence have been confirmed experimentally.
quartz තිරුවාණ, ක්වෝට්ස් A hard mineral consisting of silica, found widely in igneous and metamorphic rocks and typically occurring as colourless or white hexagonal prisms. A form of silicone dioxide.
quartz crystal ක්වෝට්ස් ස්ඵටිකය A small crystal of quartz accurately cut along certain axes so that it can be vibrated at a particular frequency, used for its piezoelectric properties to produce an electric signal of constant known frequency.
quenching මර්දනය Rapid cooling of a workpiece in water, oil or air to obtain certain material properties.
quotient එලය Ratio. A result obtained by dividing one quantity by another.
R මුලට TOP
raceway ධාවන පථය An enclosed channel of metal or nonmetallic materials designed expressly for holding wires, cables, or busbars. Raceways include, but are not limited to, rigid metal conduit, rigid nonmetallic conduit, intermediate metal conduit, liquidtight flexible conduit, flexible metallic tubing, flexible metal conduit, electrical nonmetallic tubing, electrical metallic tubing, underfloor raceways, cellular concrete floor raceways, cellular metal floor raceways, surface raceways, wireways, and busways.
rad රැඩය The unit of absorbed dose of ionising radiation. One rad is equal to the energy absorption of 100 ergs per gram of irradiated material.
radar රේඩා An acronym for RAdio Detection And Ranging. A general term now used to include any system employing microwaves for the purpose of locating, identifying, navigating, or guiding such moving objects as ships, aircraft, etc.
radial circuits කේන්ද්‍රගාමී පරිපථ Each circuit commences from the consumer unit/distribution board through an MCB/fuse of specific rating (e.g. 20A), loop into each socket outlet but ends at a socket outlet (does not return to the original fuse/mcb). No loops are formed.
radial අරීය Arranged like rays diverging from a common centre.
radian (rad) රේඩියනය The radian is SI unit of the plane angle. It is a supplementary unit. It is defined as the plane angle between two radii of a circle that cut off on the circumference an arc equal in length to the radius.
radiance විකිරණය A type of glowing from a light source like the sun.
radiant efficiency විකිරණශීලී කාර්යක්ෂමතාව Ratio of the radiant flux (power) emitted from a source to the power consumed.
radiant heat විකිරණ තාපය Heat energy transmitted by electromagnetic waves in contrast to heat transmitted by conduction or convection.
radiation විකිරණය Emission of energy as electromagnetic waves or as moving subatomic particles, especially high-energy particles which cause ionization.
radio waves රේඩියෝ තරංග Electromagnetic waves of a frequency between about 104 and 1012 Hz, as used for long-distance communication.
radio ගුවන් විදුලි The use of electromagnetic radiation to communicate electrical signals without wires. In the widest sense the term incorporates sound broadcasting, television and radar.
radioactive විකිරණශීල Emitting or relating to the emission of ionizing radiation or particles.
radio-activity විකිරණශ්‍රීලතාව The property of spontaneous disintegration possessed by certain unstable types of atomic nucleii.
radio-frequency interference, RFI ගුවන්විදුලි සංඛ්‍යාත අතුරුබාධනය Electromagnetic signals of a frequency associated with electromagnetic radiation which are coupled to a conductor either directly or as with an antenna.
radius අරය The distance from the center to the circumference of a circle or the outer surface or a sphere.
RAM, random access memory අහඹු ප්‍රවේශ මතකය A memory in which the access time is the same for all locations.
random සසම්භාවී Occurring without definite aim, reason, or pattern.
random error සසම්භාවී දෝෂය An error in measurement caused by factors which vary from one measurement to another.
rankine oR scale of temperature රැන්කයින් උෂ්ණත්ව පරිමාණය It is the absolute Fahrenheit scale, starting from absolute zero at - 459.69 oF. Can be converted to degree Fahrenheit by the addition of 459.69 oF.
rate සීඝ්‍රතාව, අනුපාතිකය Ratio between two related quantities in different units.
rated voltage ශ්‍රේණිගත වෝල්ටීයතාවය, ප්‍රමත වෝල්ටීයතාවය The voltage of electrical apparatus at which it is designed to operate.
rated ශ්‍රේණිගත, ප්‍රමත The designed value, as usually stated on the nameplate in appropriate power units.
ratepayer ප්‍රමාණ ගෙවන්නා A retail consumer of the electricity distributed by an electric utility. This includes residential, commercial and industrial users of electricity.
rating ප්‍රමාණනය, වැගයීම A classification of something based on a comparative assessment of their quality, standard, or performance. Specification of normal parameters of an electrical device such as voltage, frequency, power, power factor, current
RCCB අවශේෂ ධාරා පරිපථ කඩනය [see residual current circuit breaker]
RCD අවශේෂ ධාරා උපාංගය [see residual current device]
reactance ප්‍රතිබාධනය The non-resistive component of impedance in an AC circuit, arising from the effect of inductance or capacitance or both and causing the current to be out of phase with the voltage causing it. The part of the impedance that does not consume active power. It is the imaginary part of the impedance.
reactive power ප්‍රතික්‍රියක ජවය That component of complex power which corresponds to storage and retrieval of energy rather than consumption.
read කියවනවා The process of retrieving information from a memory.
real number තාත්වික අංකය A value of a continuous quantity that can represent a distance along a line, both in the positive and negative directions. They are distinuguishable from imaginary numbers such as quare root of minus one.
real-time pricing යතා කාලීන මිලකරණය The instantaneous pricing of electricity based on the cost of the electricity available for use at the time the electricity is demanded by the consumer.
receiver ආදායකය, රිසීවරය A receiver is the part of a radio or television set that picks up signals and converts them into sound or pictures. The part of a communications system which converts electrical waves into visible or audible form.
reciprocal පරස්පර An expression or function that is the inverse of a given quantity. It is the quantity obtained by dividing the number one by a given quantity.
recombination ප්‍රති සංයෝජනය The process of recombining things.
recovered energy නැවත ලබා ගන්නා ශක්තිය Reused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.
recovery time ප්‍රතිසංවේදන කාලය The time required for something to resume its former or usual condition following an action
rectification සෘජුකරණය The conversion of an alternating current to direct current, usually pulsating dc..
rectifier සෘජුකාරකය A rectifier is an electrical device that converts alternating current to direct current.
rectifier type meter සෘජුකාරක මීටරය A moving coil meter used together with a bridge rectifier to measure the average value of the waveform. They are usually calibrated to read the rms value of a sinusoidal waveform by multiplication by the form factor 1.1107 during calibration.
reduced low voltage system ඌනිත අඩු වෝල්ටීයතා පද්ධතිය A system in which the nominal phase to phase voltage does not exceed 110 volt and the nominal phase to earth voltage does not exceed 63.5 volt.
reduction ඌනනය The action of making something smaller or less in amount, degree, or size.
redundancy අතිරික්තතාව Duplication of elements in a system or installation to enhance the reliability or continuity of operation.
redundant විචල්‍යය Able to be omitted without loss of meaning or function.
reflected wave පරාවර්තිත තරංග A wave reflected from a junction of two or more lines. The wave that travels back to the source end of a mismatched transmission line.
reflection පරාවර්තනය Reflection is the change in direction of a wave at a boundary between two different media, so that the wave moves back into the medium it came from. The most common examples include the reflection of light, sound and surge waves.
reflection coefficient පරාවර්තන සංගුණකය A parameter that describes how much of an electromagnetic wave is reflected by an impedance discontinuity in the transmission medium.
refraction වර්තනය The bending of a wave when it enters a medium where its speed is different.
refractive index වර්තන අංකය Measure of the bending of a ray of light when passing from one medium into another.
refresh නැවත ප්‍රාණවත් කිරීම The process of renewing the contents of a dynamic memory.
refrigerator ශීතකරය A refrigerator (or fridge) is a thermally insulated compartment and a heat pump that transfers heat from the inside of the fridge to its external environment so that the inside of the fridge is cooled to a temperature below the room temperature.
regeneration පුනර්ජනනය The action or process of regenerating or being regenerated.
regenerative පුනර්ජනක Tending to or characterized by regeneration.
register ලේඛණ, අනුලැකීම, අනුලැකිය A register is an official list or record of people or things. A register is also a temporary storage area built into a CPU. A group of flip-flops capable of storing data.
register ලේඛණ A group of flip-flops capable of storing data.
regulation රෙගුලාසි, යාමනය A rule or directive made and maintained by an authority. The action or process of regulating.
regulation යාමනය, නියාමනය A term used to describe the action of holding a constant electrical value in the face of fluctuations.
regulator යාමනය,, යාමක A device for automaticaly controlling something such as to maintain a constant voltage level in a voltage regulator.
reheat ප්‍රතිතාපය To heat something again.
reinforced insulation ශක්තිමත් කරන ලද පරිවරණය Single insulation system applied to live parts which provide a degree of protection against electric shock equivalent to double insulation under the conditions specified in the relevant standard. The term 'single insulation' does not imply that the insulation must be one homogeneous piece. It may comprise several layers which cannot be tested singly as supplementary or basic insulation.
reinforcement වැර ගැන්නුම The action or process of reinforcing or strengthening.
relative සාපේක්ෂ Considered in relation or in proportion to something else.
relative humidity සාපේක්ෂ ආර්ද්රතාව The ratio of the pressure of water vapour actually present in the atmosphere to the pressure of the vapour which would be present if the vapour were saturated at the same temperature. [This is also sometimes expressed in terms of masses rather than pressure].
relative permeability සාපේක්ෂ පාරගම්යතාව Ratio of the permeability of the magnetic material to that of free space. The permeability of free space is 4p´10-7 H/m. The permeability of air is very nearly equal to the permeability of free space.
relative permittivity සාපේක්ෂ පාරවේද්‍යතාව Ratio of the permittivity of the dielectric material to that of free space. The permittivity of free space is 8.854´10-12 F/m. The permittivity of air is very nearly equal to the permittivity of free space.
relativity සාපේක්ෂතාව The dependence of various physical phenomena on relative motion of the observer and the observed objects, especially regarding the nature and behaviour of light, space, time, and gravity.
relaxation විශ්‍රාන්තිය The return of a perturbed system into equilibrium.
relay පිළියවනය An electrical switch that uses an electromagnet to move the switch from the off to on position. It takes a relatively small amount of power to turn on a relay but a relay can control something that draws much more power.
reliability; විශ්වාස්‍යතාව The guarantee of system performance at all times and under all reasonable conditions to assure constancy, quality, adequacy and economy of electricity. It is also the assurance of a continuous supply of electricity for customers at the proper voltage and frequency. Electric system reliability has two components - adequacy and security.
reluctance විරමණය A concept used in the analysis of magnetic circuits. Magnetic reluctance in a magnetic circuit is analogous to electrical resistance in an electrical circuit. Marhematically, reluctance = mmf/magnetic flux. It is the constant of proportionality between the applied mmf and the flux produced. [Unit: henry-1]
remanence අවශේෂය, ධාරණශීලතාව The magnetization left behind in a ferromagnetic material after an external magnetic field is removed.
remanent flux density අවශේෂ ස්‍රාව ඝනත්වය The value of the magnetic flux density remaining in a magnetized body when, in the absence of a self-demagnetizing field, the applied magnetic field strength is brought to zero.
remote control දුරස්ථ පාලකය The Control of an electrical device from a remote point.
renewable energy පුනර්ජනනීය බලශක්ති Energy sources that are derived from the sun or other natural processes and which can be naturally replenished. Examples include wind, solar, geothermal, hydro, photovoltaic, wood and waste. [Non-renewable energy sources include coal, oil, and gas which all exist in finite amounts.]
repowered plant නැවත යථා තත්ත්වයට පත්කර ඇති බලාගාරය An existing power facility that has been substantially rebuilt to extend its useful life.
repulsion විකර්ෂණය A force under the influence of which objects tend to move away from each other.
reregulation නැවතනියාමනය The design and implementation of regulatory practices to be applied to the remaining regulated entities after restructuring of the vertically-integrated electric utility. Reregulation could employ the same or different regulatory practices as those used before restructuring.
resellers නැවත විකුණුම්කරුවන් Companies that purchase utility service from a wholesaler and resell it to consumers.
reserve capacity සංචිත ධාරිතාව Capacity in excess of that required to carry peak load.
reserve margin සංචිත ආන්තිකය The percentage of installed capacity exceeding the expected peak demand during a specified period.
reservoir කටාරය, ආශය Most commonly, an enlarged natural or artificial lake, pond or impoundment created using a dam or lock to store water.
residential නේවාසික The residential sector is defined as private household establishments which consume energy primarily for lighting, refrigeration, cooking, heating and air conditioning.
residual ශේෂ, අවශේෂ, අවශිෂ්ට A residual is generally a quantity left over at the end of a process.
residual current circuit breaker, rccb අවශේෂ ධාරා පරිපථ කඩනය [see residual current device]
residual current device, rcd අවශේෂ ධාරා උපාංගය Devices are designed to protect both equipment and users from fault currents between the live and earth conductors. An RCD detects the residual current between the live and neutral conductors and prevents fatal electric shocks by disconnecting the supply if the detected current exceeds a safe limit (typically 30mA).
residual current අවශේෂ ධාරාව Algebraic sum of the currents in the live conductors of a circuit at a point in the electrical installation.
residual fuel oil අවශේෂ ඉන්ධන තෙල් The topped crude oil remaining after the refining operation. Residual fuel oil is used for the production of electric power and various industrial purposes.
residual voltage or discharge voltage අවශේෂ වෝල්ටීයතාවය හෝ විසර්ජන වෝල්ටීයතාවය The voltage that appears between the line and earth terminals of the surge diverter during the passage of discharge currents.
resin දුම්මල Natural resins are amorphous organic compounds which are secreted by certain plants and insects. They are usually insoluble in water but soluble in various organic solvents.
resistance ප්‍රතිරෝධය A measure of the opposition to current flow in an electrical circuit. The magnitude of potential difference (voltage) across the component when a current of one ampere passes through a component it.
resistance area (for an earth electrode only) ප්‍රතිරෝධක ප්‍රදේශය (පෘථිවි ඉලෙක්ට්‍රෝඩයක් සඳහා පමණි) The surface area of ground (around an earth electrode) on which a significant voltage gradient may exist.
resistance thermometer ප්‍රතිරෝධක උෂ්ණත්වමානය A device to measure temperature using the temperature coefficient of the material of the device (usually platinum wire).
resistivity ප්‍රතිරෝධකතාව A measure of the resistance of a given size of a specific material to electrical conduction.
resistor ප්‍රතිරෝධකය A passive two-terminal electrical component that implements electrical resistance as a circuit element.
resolution විභේදනය The abiltiy to distinguish two points as separate structures rather a single fuzzy dot. In practice, resolution is a measure of the level of detail that can be observed. The smallest change that can occur in the output for a change in the input.
resolved part විභින්න කොටස් The components in two or three Mutually independant directions (usually perpendicular).
resonance අනුනාදය Occurs when a electrical circuit naturally oscillates at a high amplitude at a specific frequency called the resonance frequency.
resonance අනුනාද A condition in which a quantity reaches maximum value. In electrical circuits, it is a condition in an RLC circuit in which the magnitude of the voltage or the current becomes a maximum or the circuit becomes purely resistive.
response ප්‍රතිචාරය A reaction to something.
response time ප්‍රතිචාර කාලය, ප්‍රතික්‍රියා කාලය The time taken for a circuit or measuring device, when subjected to a change in input signal, to change its state by a specified fraction of its total response to that change.
rest නිශ්චලතාව, නිශ්චල The state of an object being stationary relative to a particular frame of reference.
rest mass නිශ්චල ස්කන්ධය The mass of a body when at rest relative to the observer.
restoring force ප්‍රතිපාදන බලය, පිළිසකුරු බලය A force that gives rise to an equilibrium in a physical system.
restructuring ප්‍රතිව්‍යුහගතකරණය The reconfiguration of the vertically-integrated electric utility. Restructuring usually refers to separation of the various utility functions into individually-operated and-owned entities.
resultant සම්ප්‍රයුක්තය The vector (or phasor) sum of two or more vectors (or phasors).
retail company බෙදා විකුණන සමාගම A company that is authorized to sell electricity directly to industrial, commercial and residential end-users.
retail competition බෙදා විකුණන තරඟය A system under which more than one electric provider can offer to sell to retail consumers, and retail consumers are allowed to choose more than one provider from whom to purchase their electricity.
retail transaction බෙදා විකුණන ගනුදෙනුව The sale of electric power from a generating company or wholesale entity to the consumer.
retail බෙදා විකුණීම Sales covering electrical energy supplied for residential, commercial, and industrial end-use purposes.
return stroke ආපසු ගමන් පහර The very bright visible flash that we see as lightning, caused by the rapid discharge of electricity. The neutralising and main stroke in a lightning strike.
revenue ආදායම The total amount of money received by an organisation from sales of its products and/or services, gains from the sales or exchange of assets, interest and dividends earned on investments, and other increases in the owner's equity except those arising from capital adjustments.
reverse ප්‍රතිවර්ත Make something the opposite of what it was.
reverse bias ප්‍රතිලෝම නැඹුරුව A dc voltage applied to a pN junction so that the positive terminal of the voltage source connects to the N-type material and the negative terminal to the p-type material. It produces reverse current in the circuit.
reversible ප්‍රතිවර්ත්‍ Capable of being reversed so that the previous state or situation is restored.
reversible process ප්‍රතිවර්ත්‍ය කාර්යාවලිය A process whose direction can be reversed by inducing infinitesimal changes to some property of the system via its surroundings.
rewirable fuse පුනර්ජනනීය ෆියුස් It is a semi-enclosed simple fuse which can be re-wired. It consists of a short length of wire, generally of tinned copper.
rheostat ධාරා නියාමකය, ධාරාස්ථාපනය An adjustable resistor constructed so that its resistance may be changed without opening the circuit. Used to control a current by varying the resistance.
right hand rule සුරත් නීතිය A way to predict the direction of a force in a magnetic field. If your thumb points in the direction of the velocity and your fingers point in the direction of the magnetic field, your palm points in the direction of the force.
ring circuit කව පරිපථය Each circuit commences from consumer unit (or distribution board) through an MCB (or fuse) of specific rating usually 30 A, loops into each socket outlet and returns to the same MCB (or fuse) in the consumer unit (distribution board). Looping must be done for the live conductor, neutral conductor and the protective conductor in separate rings. The ring method of connection is done only for the 13 A socket outlets, as the individual 13A plugs are separately having fuses (fuses may be usually rated at 13 A or 3 A depending on the type of load).
ripple රැළිත්ත A ripple is a disturbance through a medium. A fluctuation in the intensity of a steady current or voltage.
ripple voltage රැළිති වෝල්ටීයතාව The residual periodic variation of the DC voltage within a power supply which has been derived from an alternating current source.
rise time නැඟුම් කාලය Time it takes for the leading edge of a waveform (voltage or current) to rise from its minimum to its maximum value. Usually defined as the time taken for the leading edge of a pulse or waveform to rise from 10% to 90% of its final value.
rms value or root-mean-square value ..මූ. හෝ වර්ග මධ්‍යන්‍ය මූල අගය The rms value of a periodic waveform is obtained by taking the square root of the mean of the squared waveform. It is also the same as the effective value of the waveform. For a.c. waveforms, unless otherwise specified, it is always the rms value that is specified.
ROM කියවන්න පමණක් හැකි මතකය Read only memory. Type of storage medium that permanently stores data on personal computers (PCs) and other electronic devices. ... Because ROM is read-only, it cannot be changed; it is permanent and non-volatile, meaning it also holds its memory even when power is removed.
room index K කාමර දර්ශකය Code number, representative of the geometry of a room, used in calculation of the utilization factor or the utilance. The room index is usually given by the formula K = (l x b)/h(l + b) where: l is the length of the room, b is the width and h is the distance of the luminaires above the working plane.
root mean square error වර්ග මධ්‍යන්‍ය මූල දෝෂය The standard deviation of the residuals (prediction errors). Residuals are a measure of how far from the regression line data points are
root mean square value වර්ග මධ්‍යන්‍ය මූල අගය The RMS value of a set of values (or a continuous-time waveform) is the square root of the arithmetic mean of the squares of the values.
rotor භ්‍රමකය The rotating cylindrical member of a machine, placed inside the stator with a narrow intervening air gap to allow for smooth rotation.
routine tests නෛත්‍යක පරීක්ෂා Routine tests are conducted on each and every single equipment to ensure that each equipment meets a minimum standard of quality.
rpm මිට (මිනිත්තුවට පරිභ්‍රමණ) Speed of rotation of a machine expressed in revolutions per minute.
RS-232 port RS-232 අනුක්‍රමික කවුළුව This is a serial port. A method of communicating digital information in which the data bits are transmitted sequentially over one line.
rule නියමය One of a set of explicit or understood regulations or principles governing conduct or procedure within a particular area of activity.
run of the river, ROR ගඟෙන් දුවන A type of hydroelectric generation plant whereby little or no water storage is provided, but makes use of the kinetic energy of the river flow to generate electricity.
running and quick-start capability ධාවනය සහ ඉක්මන් ආරම්භක හැකියාව Generating units that can be made available to carry load within a 30-minute period.
rupture විදාරණය An instance of breaking or bursting suddenly and completely.
S මුලට TOP
safe current නිරාපද ධාරාව A current of less than 10mA is generally considered inherently safe for humans as only currents above 10 mA can cause a shock and muscle contractions so severe that you cannot let go of whatever is shocking you. A current of 30mA or less is considered safe in the presence of residual current protection.
safety fuse නිරාපද විලායකය A device that operates to provide overcurrent protection of an electrical circuit.
sag එල්ලා වැටුම Sag is the amount of the droop or hanging of a conductor due to its own weight.
sag, voltage වෝල්ටීයතා අගාධය A voltage sag is a momentary (less than 2 seconds and more than 1 cycle) decrease in voltage outside the normal tolerance. Voltage sags are often caused by starting heavy loads, such as motors or welding equipment, and by power system faults.
sample නියැදිය Take a sample of something for analysis.
sample tests නියැදි පරීක්ෂා This is done only on a few samples of the equipment. In these the sample is tested fully, up to and including the point of breakdown.
sampling නියැදීම The reduction of a continuous-time signal to a discrete-time signal.
saponification සඑනීකරණය The chemical process of forming a soap. More particularly a deterioration by softening of caused by the action of aqueous alkali on fatty-acid constituents.
saturation සන්තෘප්තිය සංතෘප්තතාව Saturation is the state reached when an increase in applied external field (magnetic field H or electrostatic field E) cannot significantly increase the flux density (magnetiic B or electric D) of the material, so the total it more or less levels off. (It continues to increase very slowly due to the vacuum permeability or permittivity), Saturation is a characteristic of ferromagnetic and ferrimagnetic materials
sawtooth generator කියත් දැති ජනකය A signal generator whose output voltage has a sawtooth waveform and used to produce sweep voltages for cathode-ray oscilloscopes.
scalar අදිශ A quantity having only magnitude, not direction.
scaling factor පරිමාප සාධකය A number, or aproportionality constant, which multiplies some quantity to scale it.
scanning පරිලෝකනය Cause a surface to be carefully traversed by a detector in order to detect some feature and obtain an overall image.
scatter ප්‍රකිරණ The amount by which many measurements or observations of similar quantities differ.
scheduled maintenance කාලීන නඩත්තුව Any maintenance that is planned to be done ahead of time and within a predetermined period.
scheduled outage උපලේඛනගත ඇනහිටීම් The shutdown of a generating unit, transmission line, or other facility, for inspection or maintenance, in accordance with an advance schedule.
scheme පරිපාටිය A systematic arrangement for putting a particular idea into effect.
Schering bridge ෂෙරිං සේතුව An electrical bridge used for measuring the electrical properties, such as capacitance and loss tangent of components or equipment such as high voltage cables.
Schrodinger's equation ෂ්රේඩිංගර් සමීකරණය A linear partial differential equation that describes the wave function or state function of a quantum-mechanical system.
SCR, Silicone Controlled Rectifier. සිලිකොන් පාලිත සෘජුකාරකය A 3 terminal, 4 layer semiconductor current controlling device, mainly used in devices to control high power.
screen තීරය, නිවාරකය A flat panel on an electrical device, such as a measuring equipment or computer, on which images and data are displayed.
search coil සෙවුම් දඟරය A flat coil of insulated wire connected to a galvanometer, used for finding the strength of a magnetic field from the current induced in the coil when it is quickly turned over or withdrawn.
seasonal variation ආර්තව විචලනය A variable element in forecasting where the production changes on a certain seasonal trend. May be caused by the season of the year, temperature, rainfall and similar variables.
second (angle) විකලාව One second is 1/3600 of a degree, while there are 360 degrees in a circle.
second (time) තත්පරය The SI unit of time. A fundamental unit. One second is the time that elapses during 9,192,631,770 (9.192631770x109 ) cycles of the radiation produced by the transition between two levels of the cesium 133 atom [1967].
secondary ද්විතීයික That winding of a transformer which receives its energy by electromagnetic induction from the primary. A transformer may have one or more secondaries.
Security සුරක්ෂණය Ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities.
selector වරකය, තෝරනය An electric switch that selects a particular circuit or group of circuits.
selector switch තේරීම් ස්විචය A multi-position switch which can be set to the desired mode of operation.
self inductance ස්වයං ප්‍රේරතාව The coefficient of induction of a voltage in a current-carrying wire when the current in the wire is changing.
self-generation ස්වයං උත්පාදනය A generation facility dedicated to serving a particular retail consumer, usually located on the consumer's premises. The facility may either be owned directly by the retail consumer or owned by a third party with a contractual arrangement to provide electricity to meet some or all of the consumer's load.
semiconductor අර්ධ සන්නායකය, අර්ධසන්නායක An electrical conductor whose resistance decreases with rising temperature and the presence of impurities, in contrast to normal metallic conductors for which the reverse is true. Semiconductors which may be elements or compounds include germanium, silicon and selenium.
semi-dispatchable අර්ධ වශයෙන් පිටත් කළ හැකි Resources which are intermittent energy generators, such as wind and solar, combined with a technology that mitigates intermittency issues, such as backup generators and storage.
semi-enclosed fuse අර්ධ සංවෘත විලායකය [see rewirable fuse]
sensitive සංවේදී Quick to detect or respond to slight changes, signals, or influences.
sensitivity සංවේදීතාව Ratio of the output signal or response of the instrument to a change of input or measured variable.
separated extra low voltage, SELV වෙන්කළ අමතර අඩු වෝල්ටීයතාවය An extra low voltage system which is electrically separated from Earth and from other systems in such a way that a single fault cannot give rise to the risk of electric shock.
separation වෙන් කිරීම The action or state of moving or being moved apart.
separator වෙන්කුරුව A device that separates something into its constituent or distinct elements.
sequence අනුක්‍රමය A set of related events that follow each other in a particular order.
sequence components අනුක්‍රමික සංරචක [සමමිතික සංරචක] [see symmetrical components]
series ශ්‍රේණිය A number of events, or objects of a similar kind coming one after another.
series compensation ශ්‍රේණි වන්දි Insertion of reactive power elements into transmission lines to reduce line voltage drops and increases transfer capability. Influence load flow in parallel transmission lines.
series motor ශ්‍රේණි ගත මෝටරය A d.c. motor with a series connected field.
series resonance ශ්‍රේණිගත අනුනාද A resonance condition that usually occurs in series circuits, where the current becomes a maximum for a particular voltage.
series ශ්‍රේණි Two or more elements are connected in series if they are connected sequentially. Series elements have the same current through them.
service agreement සේවා ගිවිසුම An agreement entered into by the transmission customer and transmission provider.
service life සේවා ආයුෂ The length of time a piece of equipment can be expected to perform at its full capacity.
servomotor සේවා මෝටරය An actuator, usually rotary, that allows for precise control of position.
seven segment display කොටස් හතක සංදර්ශකය A display consisting of 7 linear segments arranged in such a way as to be able to produce all the 10 digits from 0 to 9 by proper excitation.
shaft ඊෂාව A long part forming the handle of a tool, a rotating machine element used to transmit power from one part to another.
shape හැඩය A geometric figure such as a square, triangle, or rectangle.
sheath කොපුව, වැස්ම The covering around the insulation of a cable.
sheet lightning පත්ර අකුණු, විහිදි අකුණ Lightning in diffused or sheet form due to reflection and diffusion by the clouds and sky. A single bolt within a cloud or between clouds can illuminate an entire cloud from the inside. This is called sheet lightning.
shellac ෂෙලැක් A yellowish natural resin secreted by the lac insect which is parasitic on certain trees.
shielding වැළහීම The process of shielding pieces of apparatus from the effect of electrostatic fields which are external to the apparatus itself. Also a protective coating that helps eliminate electromagnetic and radio frequency interference.
shift register මාරු ලේඛනය A digital circuit capable of storing and shifting binary data.
shock ප්‍රහාරය A sudden upsetting or surprising event or experience. The physical reaction or trauma caused by a discharge of electricity through a part of the body.
shock current කම්පන ධාරාව A current passing through the body of a person or livestock such as to cause electric shock and having characteristics likely to cause dangerous effects.
short circuit ලුහුවත් කරනවා, ලුහු පරිපථය, (කෙටි පරිපත ​) An electrical circuit in a device of much lower resistance than that of a normal circuit, especially one resulting from the unintended contact of components and consequent accidental diversion of the current to earth. A circuit element which has an impedance approaching zero.
short circuit current ලූහුවත් පරිපථ ධාරාවක් An overcurrent resulting from a fault of negligible impedance between live conductors having a difference in potential under normal operating conditions.
shunt compensation උපපථ වන්දි Change of reactive power at a point of a network by means of reactors, capacitors or synchronous compensators, shunt connected to the network.
shunt motor ෂන්ට් මෝටරය d.c. motor with a shunt connected field.
shunt winding උපපථ එතුම A winding so arranged as to divide the armature current and lead a portion of it through the field coil.
shunt උපපථ A component connected in parallel. A current shunt is a device for altering the amount of electric current flowing through a piece of apparatus, such as a galvanometer.
SI units SI ඒකක, ජාත්‍යන්තර ඒකක පද්ධතිය The International System of Units. A system of physical units based on the metre, kilogram, second, ampere, kelvin, candela, and mole, together with a set of prefixes to indicate multiplication or division by a power of ten.
side band පැති කලාපය The band of frequencies lying on either side of a modulated carrier wave.
siemens (S) සීමන් SI unit of electric conductance. One siemens is equal to the conductance between two points of a conductor having a resistance of 1 W. siemens is the reciprocal of the ohm.
signal සංඥාව An electrical current or voltage that is used for carrying information from one device or network to another. A visual, audible, electrical or other indication used to convey information.
signal-to-noise ratio, S/N ratio ඝෝෂාවට සංඥා අනුපාතය The ratio of desired signal level to the undesired noise level, expressed in dB.
silicon controlled rectifier, SCR සිලිකන් පාලිත සෘජුකාරක A thyristor. A four-layered semiconductor rectifier in which the flow of current between two electrodes is triggered by a signal at a third electrode
simple සරල Plain, basic, or uncomplicated in form, nature, or design.
simple harmonic motion සරල අනුවර්තී චලිතය Periodic oscillatory motion under a force proportional to the amount of displacement from an equilibrium position.
simulation සමාකරණය A research or development project where a model of some authentic phenomenon is created to imitate the operation of a real-world process or system over time and predict results.
simultaneous සමගාමී Two events are simultaneous in a given system of reference, if they occur at the same time.
simultaneously accessible parts එකවර ප්‍රවේශ විය හැකි කොටස් Conductors or conductive parts which can be touched simultaneously by a person or, in locations specifically intended for them, by livestock. Simultaneously accessible parts may be: live parts, exposed conductive parts, extraneous conductive parts, protective conductors or earth electrodes. සජීවී කොටස්, නිරාවරණය වූ සන්නායක කොටස්, බාහිර සන්නායක කොටස්, ආරක්ෂිත සන්නායක හෝ පෘථිවි ඉලෙක්ට්‍රෝඩ.
sine wave සයින් තරංග A sinusoidal periodic oscillation. The fundamental waveform from which other waveforms may be generated by combinations of various group of harmonics. The voltage and current waveforms produced from the power company generators (alternators) are basic sine waves.
sine wave, sinusoid සයින තරංගය A mathematical curve that describes a smooth periodic oscillation.
single phase තනි කලා A system in which all the voltages of the supply has the phase angle and vary in unison.
single phase line තනි අදියර විදුලි රැහැන් Carries electrical loads capable of serving the needs of residential consumers, small commercial consumers, and streetlights. It carries a relatively light load as compared to heavy duty three phrase constructions.
single phase තනි අදියර A circuit having two conductor, one of which is the live conductor and the other the neutral conductor.
single pole switch ඒක ධ්‍රැව ස්විච්චිය A switch that only has a single input and can connect only to one output.
single sweep එක් වරක් හරහා යෑම The ability of an oscilloscope to display just one window of time, thus preventing unwanted multiple displays. Necessary in the display of transient waveforms.
single-point ground තනි ලක්ෂ්‍ය භූමිය The practice of tying the power neutral ground and safety ground together at the same point, thus avoiding a differential ground potential between points in a system.
sinusoid සයිනොසොයිඩ් A signal which is having a sinusoidal waveform.
sinusoidal සයිනාකාර Having the form of a sine curve.
Skilled person පළපුරුදු පුද්ගලයා Person with technical knowledge or sufficient experience to enable him/her to avoid dangers which electricity may create.
skin effect චර්මාචරණය, බාහිරාචරණය A tendency for alternating current to flow mostly near the outer surface of an electrical conductor. The effect becomes more apparent as the frequency increases.
skin resistance චර්ම ප්‍රතිරෝධය The resistance to the flow of electric current through the skin of the human body. More than 90% of the body's resistance is at the skin. While the internal body resistance is around 300Ω,the skin resistance could vary from 1 kΩ to 100 kΩ depending on how wet or dry the skin is.
slide rule සර්පණ රූල A ruler with a sliding central strip, marked with logarithmic scales and used for making rapid calculations, especially multiplication and division.
slide wire bridge සර්පණ කම්බි සේතුව A resistance-measuring device used as part of a Wheatstone bridge and consisting essentially of a straight wire divided by a sliding contact into two parts forming the known portions of adjacent arms of the bridge.
slip ලිස්සීම The difference between the flux speed (Ns) and the rotor speed (N). It is usually expressed as a percentage of synchronous speed (Ns). Per unit speed by which the rotor falls behind the stator field. Slip is positive for induction motors and negative for induction generators.
slip ring ඇතිල්ලුම් විල්ල, ඇතිලි මුදුව An electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure.
small power producer කුඩා බලශක්ති නිෂ්පාදකයා Refers to a producer that generates at least 75% of its energy from renewable sources.
socket කෙවෙනිය A mains electricity power point mounted inside a dwelling (usually on a wall) or other building.
socket outlet බල පිටවාන, කෙවෙනි පිටවාන A device, provided with female contacts, which is intended to be installed with the fixed wiring, and intended to receive a plug. A luminaire track system is not regarded as a socket outlet system.
sodium vapour lamp සෝඩියම් පහන A gas-discharge lamp that uses sodium in an excited state to produce light at a characteristic wavelength near 589 nm.
soft iron මෘදු යකඩ Iron that has a low carbon content and is easily magnetized and demagnetized with a small hysteresis loss.
software මෘදුකාංග Programs and other operating information used by a computer.
solar cell සුර්ය කෝෂ An device which converts energy from the sun directly into electrical energy.
solar energy සූර්ය ශක්ති Energy produced and radiated from the Sun in the form of light and heat capable of producing electricity or heat.
solar thermal electric සූර්ය තාප විදුලි A process that generates electricity by converting incoming solar radiation to thermal energy.
solder පාහනය, පාස්සනවා Solder is a fusible alloy and has a melting point below 840°F, used when melted to join metallic surfaces.
solenoid පරිනාලිකාව A current-carrying coil of wire that acts like a magnet when a current passes through it. A coil of wire wound uniformly on a cylindrical former, having a length which is large compared with its radius.
solid angle ඝන කෝණය The angle subtended at the center of a sphere by an area on its surface numerically equal to the square of the radius. [Unit steradian, sr].
solid state ඝන අවස්ථාව Solid-state physics is the study of rigid matter, or solids, through methods such as quantum mechanics, crystallography, electromagnetism, and metallurgy.
solid state relay ඝන අවස්තා රිලේ Completely electronic switching device with no moving parts or contacts.
solubility ද්‍රාව්‍යතාව A chemical property referring to the ability for a given substance, to dissolve in a solvent.
sound ධ්වනිය, ශබ්දය A vibration that typically propagates as an audible wave of pressure, through a transmission medium such as a gas, liquid or solid.
source ප්‍රභවය A device from which energy or something originates.
space අවකාශය The boundless three-dimensional extent in which objects and events have relative position and direction.
space charge අභ්‍යවකාශ ආරෝපණය A cloud of free electrons (or positive ions) surrounding the cathode in an electrode assembly.
spacial distribution අවකාශයික ව්‍යාප්තිය An arrangement of a geographic phenomenon on representing values across many locations.
spacing පරතරය, පරතර ලෑම The geometric distance between two objects or parts of objects.
spark, spark discharge පුළිඟුව, පුළිඟු විසර්ජනය An abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating mediumsuch as gas or liquid.
sparsity විරලතාවය Sparsity is a database concept that defines the amount of emptiness, or sparseness..
specific gravity විශිෂ්ට ගුරුත්වය Ratio of the density of a substance to the density of a reference substance, usually water.
specific heat විශිෂ්ට තාපය නිශ්චිත තාපය The quantity of heat required to raise the temperature of unit mass through 1oC.
specimen නිදර්ශකය An item considered typical of a group,or a quantity of material for use in testing.
spectrum වර්ණාවලිය, ක්ෂාවලිය A graph or chart of a distribution, such as intensity or energy against frequency or other variable parameter. While a spectrum commonly contains the continuous distribution of a variable with no gaps, a line spectrum is a bar chart of a discrete variable such as frequncy and its harmonics.
speed of light ආලෝකයේ වේගය The speed at which light waves propagate through a material. In particular, the speed of light in a vacuum, now defined as exactly 299,792,458 metres per second.
sphere ගෝලීය A perfectly round geometrical object, where the surface is the same distance from the center at all points, in three-dimensional space.
sphere gap ගෝලාකාර පරතරය A gap between two spherical electrodes. The sphere gap method of measuring high voltage is the most reliable and is used as the standard for calibration purposes.
spheroid උපගෝලාකාර Solid figure generated by an ellipse rotating about one of its axes.
spheroid, ellipsoid ගෝලාභය A solid generated by a half-revolution of an ellipse about one of its axes. It is in fact an elongated sphere.
spike (or impulse, switching surge, lightning surge) ස්පයික් These terms refer to a voltage increase of very short duration (microsecond to millisecond). Spikes can range in amplitude from 200 V to 6,000 V and are caused by lightning, switching of heavy loads, and short circuits or power system faults in the distribution system.
spike suppressor ස්පයික් මර්දනය A device that provides protection against short duration (microsecond to millisecond) voltage increases known as spikes, impulses, transients, or high-frequency surges.
spike ස්පයික් A spike involves a sudden marked jump in voltage, which can damage electronics and corrupt or destroy data.
spinning reserve භ්‍රමණය වන සංචිතය The generating capacity running at no load and synchronized to the electric system and kept as a reserve to meet sudden increases in demand. The difference between the total available capacity of all generating sets already coupled to the system and their total actual loading.
spiral spring සර්පිල දුන්න A spring consisting of a wire coiled as a helix.
split ring පැළි වළල්ල A simple and clever device for reversing the current direction through an armature every half turn. The commutator is made from two round pieces of copper, one on each side of the spindle.
spontaneous ස්වයං Occurring as a result of a sudden impulse without premeditation or external stimulus.
spot price ස්ථාන මිල The price at which the commodity electricity is selling at for immediate delivery at a given time and place.
spot pricing ස්ථාන මිලකරණය Determination every half-hour a new price for electricity in a given region of the network. The spot market essentially schedules the cheapest generators tha are able to supply the load.
spot welding තිත් වෙල්ඩිම A process in which contacting metal surface points are joined or welded by the heat obtained produced by ohmic loss of the resistance across the surfaces to be welded.
spotlight අවධාරිත ආලෝකය, ස්ථාන ආලෝකය A small projector or lamp giving concentrated light of usually not more than 20° divergence.
spring balance දුනු තරාදිය A device in which an object to be weighed is attached to the end of a helical spring, the extension of which indicates the weight of the object on a calibrated scale.
sprites ස්ප්‍රයිට්ස් Massive but weak luminous flashes that appear directly above an active thunderstorm system and are coincident with cloud-to-ground or intra-cloud lightning strokes. Sprites are immense. They can shoot up from the top of a 8 km thundercloud to heights of 40 km or more.
spur නෙරුව A branch from a ring final circuit.
square wave කොටු තරංගය A periodic wave which alternates between two fixed amplitudes for equal lengths of time, with the time of transition between the amplitudes being negligibly small.
squirrel cage ලේන කූඩුව The rotor of an induction motor with a cylindrical winding with copper bars around the edge parallel to the axis.
squirrel cage rotor ලේනු කූඩු රොටර් This type of rotor has the simplest and most rugged construction and is almost indestructible. The rotor consists of a cylindrical core with parallel slots for carrying the rotor conductors which are not wires but heavy bars of copper, aluminium or alloys. The rotor bars are permanently short-circuited at the ends to form the winding or cage. About 90% of induction motors are squirrel cage type.
SRAM, Static RAM ස්ථිතික අහඹු ප්‍රවේශ මතකය A RAM that stores information in flip flop cells in a static manner and do not have to be refreshed unlike those of the DRAM.
St. Elmo's fire සාන්ත එල්මෝ ගින්න A weather phenomenon in which luminous plasma is created by a corona discharge from sharp or pointed objects in a strong electric field in the atmosphere, such as those generated by thunderstorms.
stability ස්ථාවරත්වය The property of a system or element by virtue of which its output will ultimately attain a steady state. The stability of a power system is its ability to develop restoring forces equal to or greater than the disturbing forces so as to maintain a state of equilibrium.
stabilizer ස්ථායිකාරකය Devices responsible for correcting the voltage of the electrical power supply to make it a stable power supply to equipment, reducing problems associated with the mains supply.
stable equilibrium ස්ථායි සමතුලිතතාව A state of equilibrium of a body or a system, such that when it is slightly perturbed it tends to return to its original position.
stable system ස්ථායී පද්ධතිය A system is stable when all the poles (roots of the denominator) of its transfer function H(s) lie in the left half of the s plane.
standard cell සම්මත කෝෂය A specially prepared primary cell which is characterised by a highly constant emf over long periods of time.
standard deviation සම්මත අපගමනය A measure of how much the members of a group differ from the mean value for the group.
standard wire gauge සම්මත කම්බි ආමානය A set of standard wire sizes, abbreviated to SWG, and given as a number from 0000000 (thickest) to 50 (thinnest).
standardization ප්‍රමාණික කිරීම The process of making something conform to a standard.
standby power supply සූදානමින් සිටින බල සැපයුම The power supply that is available to furnish electric power when the normal power supply is not available.
star connection තරු සම්බන්ධතාවය A method of connecting three elements of a three-phase electrical system at a common node, and with the three phases being taken from the remaining nodes of the elements. This is also known as “wye” connection.
starter ස්ටාරය, ක්‍රියාරම්භකය An automatic device for starting a machine.
starter ආරම්භකය A device to assist in the starting process.
static characteristic ස්ථිති ලාක්ෂණිකය An unchanging steady state condition, of a system or physical process, that is attained even after transformation or change.
static electricity ස්ථිති විද්‍යුතය An imbalance of electric charges within or on the surface of a material. The charge remains until it is able to move away by means of an electric current or electrical discharge.
stationary equipment නිශ්චල උපකරණ Electrical equipment which is either fixed, or equipment having a mass exceeding 18 kg and not provided with a carrying handle.
statistical සංඛ්‍යාන Relating to the use of statistics.
statistical impulse voltage සංඛ්යානමය ආවේග වෝල්ටීයතාවය This is the switching or lightning overvoltage applied to equipment as a result of an event of one specific type on the system (line energising, reclosing, fault occurrence, lightning discharge, etc), the peak value of which has a 2% probability of being exceeded.
statistical impulse withstand voltage සංඛ්යානමය ආවේග වෝල්ටීයතාවය This is the peak value of a switching or lightning impulse test voltage at which insulation exhibits, under the specified conditions, a 90% probability of withstand. In practice, there is no 100% probability of withstand voltage. Thus the value chosen is that which has a 10% probability of breakdown.
statistics සංඛ්‍යාතිය The discipline that concerns the collection, organization, display, analysis, interpretation and presentation of data.
stator ස්ථායුකය The stationary member of a machine in the form of an hollow cylinder inside which the rotor will be placed with a narrow intervening air gap.
steady state response ස්ථාවර තත්වයේ ප්‍රතිචාරය Behaviour of a circuit after a long time when steady conditions have been reached after an external excitation.
steam plant (conventional) වාෂ්ප බලාගාරය (සාම්ප්‍රදායික) A plant in which the prime mover is a steam turbine. The steam used to drive the turbine is produced in a boiler where fossil fuels are burned.
steam turbine හුමාල ටර්බයිම A turbine in which a high-velocity jet of steam rotates the blades of a turbine to convert thermal energy to rotational energy.
Steinmetz law ස්ටයින්මෙට්ස් නියමය An emperical equation that gives the hysteresis energy loss per cycle per unit volume caused by a varying magnetic field. Ph = η.Bma where "η" is the Steinmetz coefficient and "a" is the Steinmetz index.
step down transformer අවකර පරිණාමකය A transformer that reduces the voltage from primary to secondary.
step function පියගැට ශ්‍රිතය A function that increases or decreases abruptly from one constant value to another constant value. It is mathematically undefined at the transition point in that it has a range of values between the two limits at that point.
step leaders පියවර නායකයන් Thin, luminous feelers, caused by electrical breakdown in a cloud, that move in short bursts, or steps, and precede lightning strikes. Lightning begins in the negatively charged region at the base of a cloud. Here, thin, barely luminous feelers called step leaders zigzag through the cloud and can travel to the earth.
step response පියවර ප්‍රතිචාරය Behaviour of a circuit when the excitation is the unit step function. The excitation function may be a voltage or a current.
step up transformer අධිකර පරිණාමකය A transformer that increases the voltage from primary to secondary.
step voltage පියවර වෝල්ටීයතාවය The difference in surface potential experienced by a person bridging a distance of 1 m with his feet without contacting any other grounded structure.
step waveform පියවර තරංග A waveform which has one level (usually zero) prior to zero time and another level after time zero.
stepped leader පියවර නියමුවා The initial streamer of a lightning discharge, which advances towards earth in a step-like manner.
steradian (sr) ස්ටරේඩියනය The steradian is SI unit of the solid angle. It is a supplementary unit. It is defined as the solid angle that, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere.
stop watch විරාම ඝටිකාව A special watch designed to measure the amount of time that elapses between its activation (start) and deactivation (stop), with ability to zero the display.
storage ගබඩා කිරීම Energy storage is the capture of energy produced at one time for use at a later time. Storage may be in one of many forms including chemical, gravitational potential, electricity, elevated temperature and kinetic.
strategic conservation උපායමාර්ගික සංරක්ෂණය Strategic conservation results from load reductions occurring in all or nearly all time periods. This strategy can be induced by price of electricity, energy-efficient equipment, or decreasing usage of equipment.
strategic load growth උපායමාර්ගික පැටවීම් වර්ධනය A form of load building designed to increase efficiency in a power system. This load shape objective can be induced by the price of electricity and by the switching of fuel technologies (from gas to electric).
stray capacitance අන්‍යම් ධාරණාව An unwanted capacitance that exists between the parts of an electrical circuit or equipment because of the proximity to each other.
stray coupling අයාලේ සම්බන්ධය Capacitive coupling that may occur between adjacent arms, sources, detector, leads etc.
stray field අනියම් ක්ෂේත්‍රය The field that is present without the presence of energisation.
streamer mechanism දහරුව උපක්‍රමය The development of a spark discharge directly from a single avalanche.
streamer රශ්මි කදම්බය, දහරුව A ribbon like discharge. A filamentary electrical discharge in the air near the electrode creating the electric field.
stress ප්‍රත්‍යාබලය The force per unit area applied to a material. Electric field stress is the stress endured by insulation when exposed to high voltage electrical fields.
stretched wire ඇදි කම්බිය A wire that has been stretched between two points.
stroboscope භ්‍රමේක්ෂය Any device used to study, measure, balance, or otherwise alter the motion of a moving, rotating, or vibrating body by making it appear to slow down or stop with the use of pulsed bursts of light or by viewing it through intermittent openings in a revolving disk.
submarine cable සබ්මැරීන් කේබලය A cable laid on the sea bed to carry telecommunication signals between land-based stations.
subscript යටකුර A character (number or letter) that is printed slightly below and to the side (usually right) of the main character.
substation උපස්ථානය A facility used for switching and/or changing or regulating the voltage of electricity. Service equipment, line transformer installations, or minor distribution or transmission equipment are not classified as substations.
successive අනුයාත Following one another without a break.
sulphur (in coal) ගන්ධක (ගල් අඟුරු වල), ගෙන්දගම්; සල්පර් One of the elements present in varying quantities in coal which contributes to environmental degradation when coal is burned. In terms of sulphur content by weight, coal is generally classified as low (less than or equal to 1 percent), medium (greater than 1 percent and less than or equal to 3 percent), and high (greater than 3 percent).
summation සමාකලනය The process of adding things together.
summing amplifier එකතු කරන වර්ධකය An Op Amp that combines several inputs and produces an output that is the weighted sum of the inputs.
sunspot හිරු ලපය A patch that appears, from time to time, on the surface of the sun. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Thus they appear dark in contrast to its surroundings.
super-conductivity සුපිරි සන්නායකතාව The electrical resistance of a metal or alloy which decreases with decrease in temperature and becoming vanishingly small at a finite temperature.
superconductor අධිසන්නායකය A material that can conduct electricity or transport electrons from one atom to another with no (or negligible) resistance.
supercooling අධිශීතනය The process of lowering the temperature of a liquid or a gas below its freezing point without it becoming a solid.
superficial පෘෂ්ඨීය Existing or occurring at or on the surface.
superheated steam අධිතප්ත හුමාලය Steam at a temperature higher than its vaporization (boiling) point at the absolute pressure where the temperature is measured.
superimposed අධිස්ථාපිත Placed over something else, so that both things are still evident.
superposition අධිස්ථාපනය The superposition principle states that the results in a circuit due to independent sources can be superposed to give the resultant quantity.
supersaturated අධිසන්තෘප්ත A concentration of a vapor that has a higher partial pressure than the vapor pressure of that compound. It can also be solution that contains more of the dissolved material than could be dissolved by the solvent under normal circumstances.
superscript උඩුකුර A character (number or letter) that is printed slightly above and to the side (usually right) of the main character.
supplementary insulation අතිරේක පරිවරණය In dependent insulation applied in addition to basic insulation in order to provide protection against electric shock in the event of a failure of basic insulation.
supplier සැපයුම්කරු A person or corporation, generator, broker, marketer, aggregator or any other entity, that sells electricity to consumers, using the transmission or distribution facilities of an electric distribution company.
supply mains ප්‍රධාන සැපයුම් Permanently installed power source which may also be used to supply electrical apparatus
supply, supply system සැපයුම, සැපයුම් ක්‍රමය A component that supplies power to at least one electric load.
supply-side management සැපයුම් පාර්ශවීය කළමනාකරණය Steps utilities take to manage their generating and transmission facilities for maximum efficiency.
supply-side සැපයුම් පැත්ත Technologies that pertain to the generation of electricity.
surface conductivity පෘෂ්ඨික සන්නායකතාව The conductivity of the surface layer of an insulator having a higher ionic concentration than the bulk of the insulator. Inverse of surface resistivity.
surface contamination මතුපිට දූෂණය Impurities that bond or settle on metal surfaces and affect the properties of the metal.
surface flashover මතුපිට පිටිසැණෙළිය Surface flashover is a breakdown of the medium in which the solid is immersed. The role of the solid dielectric is only to distort the field so that the electric strength of the medium is exceeded.
surface resistivity පෘෂ්ඨික ප්‍රතිරෝධකතාව The resistance to leakage current along the surface of an insulating material, of distance equal to the width of contact.
surface tension පෘෂ්ඨික ආතතිය The tension of the surface film of a liquid caused by the attraction of the particles in the surface layer by the bulk of the liquid.
surge arrester සර්ජන සීමා කිරීමේ ආරක්ෂිත උපාංගය A protective device for limiting surge voltages on equipment by discharging or bypassing surge current. It prevents continued flow of follow through current to earth, and is capable of repeating these functions as specified.
surge diverter සර්ජන හරවනය A piece of equipment that diverts excess voltages (caused by surges) to earth, thus protecting electrical and electronic equipment..
surge impedance සර්ජන සම්බාධනය Is the characteristic impedance of a transmission line. It relates the peak value of the surge voltage to the peak value of the surge current.
surge voltage සර්ජන වෝල්ටීයතාව The sudden rise in excessive voltage.
surge ක්ෂෝභය, සර්ජන A transient (or momentary) wave of current, potential, or power in an electric circuit. The word "surge" has different meanings to different engineering communities. To the protection engineer a "surge" is a transient overvoltage with a duration of a few microseconds, i.e., a spike. To others a "surge" is a momentary overvoltage lasting up to a few seconds, a swell.
surplus energy අතිරික්ත ශක්තිය Excess firm energy available from a utility or region for which there is no market at the established rates.
susceptance ග්‍රාහණය That part of the admittance that does not consume active power. The imaginary part of admittance. For a pure reactance, it is also the inverse of the reactance.
sweep circuit පිරිසැරුම් පරිපථය An oscillatory circuit designed to control the sweep in an oscilloscope.
sweep frequency response analysis, SFRA ස්වීප් සංඛ්‍යාත ප්‍රතිචාර විශ්ලේෂණය SFRA is a method to evaluate the integrity of core, windings and clamping structures within power transformers by measuring their electrical transfer functions over a wide frequency range.
sweep පිරිසැරුම. අමදිනවා To cause an electron beam in the CRT, to sweep horizontally across a phosphorescent screen.
switch ස්විච්චිය An electrical component that can "make" or "break" an electrical circuit.
switch ස්විච්චිය A mechanical device capable of making, carrying and breaking current under normal circuit conditions, which may include specified operating overload conditions, and also of carrying for a specified time currents under specified abnormal circuit conditions such as those of short circuit. It may also be capable of making, but not breaking, short circuit currents.
switch, linked බැදි ස්විච්චිය A switch the contacts of which are so arranged as to make or break all poles simultaneously or in a definite sequence.
switchboard ස්විච්ය පුවරුව A device that directs electricity from one or more sources of supply to several smaller regions of usage.
switchgear ස්විච්චිපන්න Composed of electrical disconnect switches, fuses or circuit breakers used to control, protect and isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream.
switching station ස්විච්චිලෑම ස්ථානය Facility equipment used to tie together two or more electric circuits through switches. The switches are selectively arranged to permit a circuit to be disconnected, or to change the electric connection between the circuits.
symmetrical සමමිතික Symmetry means that one shape becomes exactly like another when you move it in some way.
symmetrical components සමමිතික සංරචක The analysis of an unbalanced three phase system into three balanced components, namely the positive sequence, negative sequence and zero sequence.
synchronization සමමුහුර්තකරණය Synchronization is the process of matching the speed and frequency of a generator or other source to the power network.
synchronous machine සමමුහුර්ත යන්ත්‍රය A machine which runs at a fixed speed, dependant on the frequency, called the synchronous speed. The machine speed is thus independent of the load.
synchronous motor සමමුහුර්තක මෝටරය AC motor in which, at steady state, the rotation of the shaft is synchronized with the frequency of the supply current. The rotation period is exactly equal to an integral number of AC cycles.
synchronous speed සමමුහුර්ත වේගය A mechanical speed related to the electrical frequency by number of pairs of poles. n = f/p rps = 60f/p rpm
synthesis සංශ්ලේෂණය The combination of components or elements to form a connected whole.
synthetic oil කෘතිම තෙල් Oil produced by artificial means and having similar properties to mineral oil.
system (electric) පද්ධතිය (විදුලි) Physically connected generation, transmission, and distribution facilities operated as an integrated unit under one central management.
system peak demand පද්ධතියේ උපරිම ඉල්ලුම The highest demand value that has occurred during a specified period for the utility system.
T මුලට TOP
tachometer භ්‍රමවේගමානය An instrument which measures the speed of a machine from its rotating shaft (in rpm).
tangent ටැන්ජනය A straight line or plane, touching, but not intersecting, a curve or curved surface.
tangential field ස්පර්ශී ක්ෂේත්‍රය A field that is in a direction that is a tangent to a curve or given shape. For example, paper can withstand much lower tangential fields than radial fields.
target market ඉලක්ක වෙළඳපල A specific group of people or geographical area that has been identified as the primary buyers of a product or service.
tariff අය ක්‍රමය, තීරු ගාස්තු A document, approved by the responsible regulatory agency, listing the terms and conditions, including a schedule or prices, under which utility services will be provided.
Taylor expansion ටේලර් ප්‍රසාරණය A representation of a function as an infinite sum of terms that are calculated from the values of the function's derivatives at a single point.
tebi (Ti) ටෙබි Binary multiple prefix corresponding to terabinary or 240 or (210)4 or 10244. [IEC 1998]
telecommunications විදුලි සංදේශ The communication of signals, data, sounds or images over a distance by wire and wireless transmission.
telegraph දූරරේඛය, විදුලි පණිවුඩය A method of transmitting messages over a distance using electrical impulses sent through wires, using the morse code (creating signals by making and breaking an electrical connection).
telemetering දුරමානනය The transmission of measuring, alarm and control signals to and from remote station controls and a central monitoring location.
telephone, phone දුරකථනය A telecommunications device that permits two or more users to converse when they are physically at different locations and thus too far apart to be heard directly.
temperature උෂ්ණත්ව The intensity of heat present in a substance or object, especially as expressed according to a comparative.
temperature coefficient උෂ්ණත්ව සංගුණකය A coefficient that describes the relative change of a physical property associated with a given change in temperature.
tensile strength ආතත්‍ය ප්‍රබලතාව A measure of the force required to pull something, such as a wire, to the point where it breaks.
tera (T) ටෙරා Decimal multiple prefix corresponding to Trillion (US) or 1012.
terminal අග්‍රය A point of connection for closing an electric circuit. Point at which a condcutor from a component, device or network comes to an end. It is also the electrical connector at the endpoint where external circuits can be connected.
terminal block පර්යන්ත කුට්ටිය An insulating base equipped with terminals for connecting wires.
tertiary winding තෘතියික එතුම A thrid winding in addition to the primary and secondary windings in a transformer in order to provide path for the harmonics produced in the transformer or to provide an additional voltage for station auxiliaries.
tesla (T) ටෙස්ලාව SI unit of magnetic flux density. One tesla is defined as the field intensity generating one newton of force per ampere of current per meter of conductor.
test පරීක්ෂාව, පරීක්ෂා කිරීම A procedure intended to establish the quality, performance, or reliability of something, especially before it is commissioned for use.
test specimen පරීක්ෂා නිදර්ශකය A sample prepared to conform to the requirements stated in the standard specification for the testing that will be performed.
testing පරීක්ෂා කිරීම The process of verifying the properties of an equipment by a process of application and measurement.
thermal තාප Relating to or caused by heat or by changes in temperature.
thermal breakdown තාප බිඳවැටීම Heat is generated continuously in electrically stressed insulation by dielectric losses, which is transferred to the surrounding medium by conduction through the solid dielectric and by radiation from its outer surfaces. If the heat generated exceeds the heat lost to the surroundings, the temperature of the insulation increases leading ultimately to thermal breakdown if a stable temperature is not reached.
thermal conductivity තාප සන්නායකතාව The rate at which heat is transferred by conduction through a unit cross-section area of a material, when a temperature gradient exits perpendicular to the area.
thermal mechanism තාප යාන්ත්‍රණය The thermal mechanism uses a heat sensitive bimetal element to operate the circuit breaker in the event of an overcurrent.
thermal ohm තාපජ ඕමය The resistance of a path through which a temperature difference of 10C produces a heat flow of 1 watt.
thermal overload protector තාප අධිපැටවුම් ආරක්ෂකය Device which protects motor windings from excessive temperature by opening a set of contacts.
thermal radiation තාප විකිරණය The emission of electromagnetic waves from matter that has a temperature greater than absolute zero.
thermal resistance තාපජ ප්‍රතිරෝධය Opposition to the flow of heat. The ratio of the temperature difference between the two faces of a material to the rate of heat flow per unit area.
thermal resistivity තාප ප්‍රතිරෝධකතාව The thermal resistivity is the temperature drop in degree celsius produced by the flow of 1 watt between the opposite faces of a metre cube of the material.
thermistor තමිස්ටරය An electrical resistor composed of semiconductor material, the electrical resistance of which varies rapidly with increase of temperature.
thermocouple තාප විද්‍යුත් යුග්මය A device for the measurement of temperature using a bimetallic strip ( two dissimilar electrical conductors joined together to form two junctions at differing temperatures. A Peltier emf is generated when the the two junctions of the circuit are kept at different temperatures.
thermoelectric තාප විද්‍යුත් The direct conversion of temperature differences to electric voltage and vice versa.
thermometer උෂ්ණත්වමිතිය An instrument for measuring temperature. Originally it consisted of a narrow, hermetically sealed glass tube marked with graduations and having at one end a bulb containing mercury or alcohol which extends along the tube as it expands.
thermoplastic තාපසුවිකාර්ය ප්ලාස්ටික් Substance which becomes plastic on being heated. A plastic material which can be repeatedly melted or softened by heat without change of properties.
thermoset තාප න්‍යස්ථය Irreversible hardening by curing from a soft solid or viscous liquid.
thermosetting plastics තාපස්ථාපන ප්ලාස්ටික් Plastics which, having once been subjected to heat and pressure lose their plasticity.
thermostat උෂ්ණත්ව පාලකය, උෂ්ණත්ව ස්ථාපය A device that automatically activates a device when the temperature reaches a set point.
Thevenin theorem, Thevenin's Theorem තෙවනින් ප්‍රමේයය Any linear two-terminal circuit containing several voltages and impedances can be replaced by just one single equivalent voltage source, known as the Thevenin's voltage, in series with a single equivalent impedance, known as Thevenin's impedance.
three phase ත්‍රි කලා A common method of alternating current electric . It is a type of polyphase system and is the most common method used by electrical grids worldwide to transfer power through three live terminals and/or 1 neutral terminals.
three phase circuit ත්‍රිකලා පරිපථය A combination of circuits energized by three alternating sources which differ in phase usually by one third of a cycle (120o). A three phase circuit may be three wire or four wire with the fourth wire being the neutral wire.
three wire system තුන් කම්බි පිළිවෙළ A three-wire system employs three conductors to supply a three-phase circuit without a neutral.
threshold දේහලිය A threshold is a level or limit on a scale which when reached, something happens.
thunder ගිගුරුම The sound that follows a flash of lightning and is caused by the sudden expansion of the air in the path of the electrical discharge. This explosive heat produces a massive, deafening shock wave - thunder.
thunderbolt අකුණ A single discharge of lightning with the accompanying thunder.
thundercloud අකුණු වලාව A cumulonimbus cloud with a towering or spreading top, like an anvil, charged with electricity and producing lightning.
thyristor, SCR තයිරිස්ටර් A silicon controlled rectifier is a solid-state switching devicethat only allows current to flow when a control voltage is applied to it's gate terminal. A four-layer semiconductor device that acts as a latch.
tidal power උදම් ජවය A form of hydropower that converts the energy obtained from the daily tides into electric power.
tidal wave උදම් තරංගය An exceptionally large ocean wave, especially one caused by an underwater earthquake.
time base කාල පාදය A part of an electronic circuit having a signal waveform varying in a desired manner with time, such as for an oscillscope. A linear time base is obtained with a saw-tooth waveform.
time constant කාල නියතය The time constant of a circuit is the time required for the state of the circuit to change from the initial state to the final state at the initial rate of change.
time domain analysis කාල වසම් විශ්ලේෂණය Analysis of mathematical functions, physical signals or time series of power system data, with respect to time..
time-of-day rate දවසේ වේලාව අනුපාතය Electricity prices that vary depending on the time periods in which the energy is consumed. In a time-of-day rate structure, higher prices are charged during utility peak-load times. Such rates can provide an incentive for consumers to curb power use during peak times.
TN system TN පද්ධතිය A system having one or more points of the source of energy directly earthed, the exposed conductive parts of the installation being connected to that point by protective conductors.
TNC system TNC පද්ධතිය A system in which neutral and protective functions are combined in a single conductor throughout the system,
TNCS system TNCS පද්ධතිය A system in which neutral and protective functions are combined in a single conductor in part of the system,
TNS system TNS පද්ධතිය In this earthing system, the supplier provides separate Neutral and Protective conductors throughout the system. The Protective Conductor is connected to the neutral of the source. All exposed conductive parts of a consumer's installation are connected to the Protective Conductor provided by the supplier via. the main earthing terminal of the consumer's installation.
tolerance සහනය The permissible limit of variation in the property.
ton ටොන් An imperial unit of weight. 1 ton = 1.016 tonnes = 1016 kg
tonne, metric tonne මීටර ටොනය An unit of weight. 1 tonne = 1000 kg
tool මෙවලම, ආයුධය Object (e.g. screwdriver) which may be used to secure or release fasteners or to make adjustments.
topology ස්ථල විද්‍යාව Deals with the structure of an interconnected system. Involving geometric properties of network.
toroid තොරොයිඩය A circular core with a circular cross-section used in transformers. It is shaped like a donut and provides a path with minimum leakage.
toroidal transformer තොරොයිඩ පරිණාමකය A power transformer with a toroidal core on which the primary and secondary coils are wound.
torque ව්‍යවර්තය The twisting force that tends to cause rotation. Product of a force and the perpendicular distance between the force and the axis of action.
torr ටෝ (අර්ධරික්තයන් මිනීමේ ඒකකය) Unit of pressure. A non-SI unit of pressure, now defined as 1/760 of an atmosphere. Originally, one torr was intended to be the same as one "millimeter of mercury". 1 torr = 133.323 pa
total harmonic distortion, THD පූර්ණ ප්‍රසංවාදී විකෘති කිරීම The effective value of all the harmonics taken together expressed as a ratio of the effective value of the fundamental.
touch voltage ස්පර්ශ වෝල්ටීයතාවය The potential difference between the ground potential rise (GPR) and the surface potential at the point where a person is standing where at the same time having his hands in contact with a grounded structure. GPR defined as the maximum voltage that a station grounding grid may attain relative to a distant grounding point assumed to be at the potential of remote earth. The touch voltage could be from hand to hand also.
tower කුළුණ A structure (usually steel) found along transmission lines which is used to support conductors.
Townsend avalanche ටවුන්ඩ්සෙන්ඩ් ඕසය A gas ionisation process where free electrons are accelerated by an electric field, collide with gas molecules, and consequently free secondary electrons.
trace හෝඩුවාවක් The visual representation of an individual signal on a CRT.
tracking ඉලියීම Tracking is the formation of a permanent conducting path across a surface of the insulation, and in most cases the conduction (carbon path) results from degradation of the insulation itself leading to a bridge between the electrodes. Tracking occurs in organic materials.
tractive force ප්‍රකර්ෂණ බලය The force used to generate motion between a body and a tangential surface, commonly through the use of dry friction.
transducer පාරනායකය A device to condition and transform a specific physical quantity to a specific variable output electrical signal proportional to the input signal. Typical inputs include variable pressure, level, voltage or current. A transducer must be specifically designed to be compatible with the input/output requirements of the total system.
transfer admittance සංක්‍රමණ ප්‍රවේශ්‍යතාව A transfer function in which the output quantity is a current and the input quantity a voltage.
transfer function මාරු ශ්‍රිතය, මාරුකිරීමේ කාර්යය The ratio of the response of a circuit to the input.
transfer impedance සංක්‍රාමණ සම්බාධනය The ratio of the phasor representing the input source voltage to the phasor representing the output load current.
transferred voltage මාරුකළ වෝල්ටීයතාවය This is a special case of the touch voltage where the voltage is transferred into or out of the station by a conductor grounded at a remote point or at the station ground, respectively.
transform පරිණාමක Change a function in one domain to an equivalent function in another domain.
transformation පරිණාමණය Change of one form variable or substance into another.
transformer පරිණාමකය, ට්‍රාන්ස්ෆෝමරය A static electric device consisting of a single winding, or two or more coupled windings, used to transfer power by electromagnetic induction between circuits at the same frequency, usually with transformed values of voltage and current.
transformer winding පරිණාමක එතුම Transformers are constructed by assembling a number of windings on a magnetic core. They usually have a primary winding and a secondary winding and sometimes a tertiary winging. Further, for three phase transformers, these are repeated for each phase.
transient අස්ථිර A phenomenon of a non-repetitive nature caused by a sudden change in conditions that persist for a relatively short time after the change.
transient response අනිත්‍ය ප්‍රතිචාරය, අස්ථිර ප්‍රතිචාර The response of a system to a sudden change from an equilibrium state.
transistor ට්‍රාන්සිස්ටරය A semiconductor device with three layers, capable of amplification in addition to rectification.
transit time සංක්‍රාන්ති කාලය The time taken for the voltage applied at one end to appear at the other end.
transmission සම්ප්‍රේෂණ The bulk movement of electrical energy from a generating site to a distribution site using high-voltage lines and towers.
transmission and distribution losses, T & D losses සම්ප්‍රේෂණය සහ බෙදා හැරීම හානිය Losses that result from the friction that energy must overcome as it moves through wires to travel from the generation facility to the consumer. Because of losses, the demand produced by the utility is greater than the demand that shows up on the consumer bills.
transmission and distribution system, T & D system සම්ප්‍රේෂණ සහ බෙදා හැරීමේ පද්ධතිය An interconnected group of electric transmission lines and associated equipment for the movement or transfer or electric energy in bulk between points of supply and points at which it is transformed for delivery to the ultimate consumers.
transmission and distribution, T & D සම්ප්‍රේෂණය සහ බෙදා හැරීම The process of delivering electricity from generation plants to homes and businesses. Transmission is considered to end when the energy is transformed for distribution to the consumer.
transmission line සම්ප්‍රේෂණ මඟ A set of electrical conductors, that carry electric power at high voltage from generating plants to distribution substations. Transmission lines are held high above the ground on transmission towers.
transmission system (Electric) සම්ප්‍රේෂණ පද්ධතිය (විදුලි) An interconnected group of electric transmission lines and associated equipment for moving or transferring electric energy in bulk between points of supply and points at which it is transformed for delivery over the distribution system lines to consumers, or is delivered to other electric systems.
transmitted wave සම්ප්‍රේෂිත තරංග The transmitted wave is the one that moves away from the Junction on another line connected to the same junction as the incident wave.
transmitter සම්ප්‍රේෂකය An electronic device used in telecommunications to produce signals in order to transmit or send data through air.
transmitting utility සම්ප්‍රේෂණ උපයෝගීතාව Regulated entity which owns, and may construct and maintain, wire used to transmit wholesale power. It is regulated to provide non-discriminatory connections, comparable service and cost recovery. Any electric utility, qualifying cogeneration facility, qualifying small power production facility, or Federal power marketing agency which owns or operates electric power transmission facilities which are used for the sale of electric energy at wholesale.
transport පරිවහන Movement of humans and goods from one location to another.
transpose පෙරළුම To transpose is to periodically swap the positions of the conductors of a three-phase transmission line, in order to reduce asymmetry of parameters
transpose of matrix න්‍යාසයේ පෙරළුම Transpose is a process of swapping the rows into columns and vice-versa of a matrix.
travelling wave චලන තරංගය The current and voltage surge waves which effectively travel from the one end of a transmission line to the other end without a significant change in waveshape.
traverse-mode noise තීර්යක් මාදිලියේ ඝෝෂාව Often used as a synonym for normal-mode noise, it more clearly relates to noise that is the result of the conversion of common-mode noise to normal-mode noise after it passes through a transformer.
tree of a network ජාලයක ගසක් A graph of the network with some of the links removed in such a way so as to leave all the nodes connected together by the graph, but so as not to have any loop left in the network.
triac දෙපැත්තටම සන්නායක කළ හැකි තයිරිස්ටරය A thyristor that can conductor in both directions. Because of this, it is useful for controlling alternating current. It is the equivalent of two SCRs in parallel with opposite polarities.
triangle of forces බල ත්‍රිකෝණය If three forces acting at the same point can be represented in magnitude and direction by the three sides of a triangle, taken in order, they will be in equilibrium.
triboelectricity ආඝර්ෂ විද්‍යුතය Refers to the electrification of dissimilar materials, or objects therefrom, occurring due to rubbing action causing seperation of charges.
trickle charge වෑස්සුම් ආරෝපණය With the trickle charging process, the battery receives a constant voltage feeding a low current. Constant use of this method dries the electrolyte and corrodes the plate, reducing potential battery service life by up to 50 percent.
trigger ප්‍රේරකය, පුරන, ක්‍රියාරම්භක A trigger is a system that uses criteria to rapidly decide the occurence of a predefined event. For example, the signal used to initiate a sweep on an oscilloscope and determine the beginning point of the trace.
trigger circuit පුරන පරිපථය A circuit in which an action is initiated by an input pulse.
trigger level ප්‍රේරක මට්ටම The instantaneous level that a trigger source signal must reach before a sweep is initiated by the trigger circuit.
triode ත්‍රියෝඩය A thermionic valve having three electrodes.
tropical නිවර්තන Typical of the the region of the Earth surrounding the Equator known as the tropics.
trough ද්‍රෝණිකාව A trough is the minimum or lowest point in a cycle.
true value සත්‍ය වටිනාකම Average value of the infinite number of measurements, when the average deviation tends to become zero.
TT system TT පද්ධතිය A system having one point of the source of energy directly earthed, the exposed conductive parts of the installation being connected to earth electrodes electrically independent of the earth electrodes of the source. An earthing system where all exposed conductive parts of an installation are connected to an earth electrode provided by the consumer which is electrically independent of the Source earth.
tungsten filament ටංස්ටන් සූත්‍රිකාව The metal filament normally used in incandescent light bulbs.
tuning fork සරසුල A two-pronged steel device which vibrates when struck to give a note of specific pitch.
tunnel effect උමං ආචරණය The passage of an electron through a narrow potential barrier in a semiconductor, despite the fact that, according to classical theory, the electron does not possess sufficient energy to surmount the barrier.
turbine ජලරෝදය, ටබයිම, තලබමරය A machine for generating rotary mechanical power from the energy of a stream of fluid (such as air, water, steam, or hot gas). Turbines convert the kinetic energy of fluids to mechanical energy. It generally consists of a series of curved vanes emanating from an axis that is turned by forcing the fluid past the vanes.
turbo electric ටබෝ විද්‍යුත් A turbo-electric device or system is uses an electric generator driven by a turbine.
turn වටය, වෙළුම Each loop of wire in a coil is called a turn.
TVSS, Transient voltage Surge Suppressor අස්ථිර වෝල්ටීයතා සර්ජ් මර්ධකය A device designed to protect connected devices from transient voltages.
two dimensional problem ද්විමාන ගැටලුව A problem that can be defined in terms of measured in length and width, with no depth.
two port network, two-port network ද්වි තොට, තොට දෙකේ ජාලය A black box network which has two independant ports and modelled as the relationships between the four external variables - voltage and current at each of the the two ports.
two terminal network ද්වි අග්‍ර ඵලය A single port electrical network with two terminals having the entering and exiting currents.
two way switch, two-way switch ද්වි මාර්ග ස්විච්චිය, දෙමං ස්විච්චය A special switch with one input and two possible output terminals used used to switch on and off a lamp from two places. Very useful in places such as a staircase or a long corridor.
type tests වර්ග කළ පරීක්ෂණ These tests are done to ensure that the particular design is suitable for a specific purpose. They are normally done either at design stage, or when a purchaser (of large orders) requires them to be done.
U මුලට TOP
ultra high frequency, UHF අති උච්ච සංඛ්‍යාතය, අත්‍යුච්ච සංඛ්‍යාතය The band of electromagnetic radiation with a frequency range 300 MHz to 3 GHz. This band is also known as the decimeter band, with a wavelength ranging from 1 m to 1 dm.
ultrahigh voltage transmission, UHV transmission අති උච්ච වෝල්ටීයතා සම්ප්‍රේෂණය Transporting electricity over bulk-power lines at voltage greater than 800 kilovolt.
ultraviolet පාරජම්බුල Beyond violet: violet being the color of the highest frequencies of visible light.
ultra-violet radiation, ultraviolet radiation, UV radiation අධි වයලට් විකිරණ, පාරජම්බුල විකිරණය Electromagnetic radiation in the wavelength range of approximately 400 nm to 500 nm. These fall between the visible light and the X-rays.
unbalanced three phase system අසමතුලිත තෙකලා පද්ධතිය A three phase system in which either the supply or the load or both are not fully balanced.
unbundling නොබැඳීම Disaggregating electric utility service into its basic components and offering each component separately for sale with separate rates for each component.  For example, generation, transmission and distribution could be unbundled and offered as discrete services.
uncertainties අවිනිශ්චිතතාවයන් Uncertainties are factors over which the utility has little or no foreknowledge, and include load growth, fuel prices, or regulatory changes. Uncertainties are modeled in a probabilistic manner. However, in the Detailed Workbook, you may find it is more convenient to treat uncertainties as "unknown but bounded" variables without assuming a probabilistic structure. A specified uncertainty is a specific value taken on by an uncertainty factor (e.g. 3 percent per year for load growth). A future uncertainty is a combination of specified uncertainties (e.g. 3 percent per year load growth, 1 percent per year real coal and oil price escalation, and 2.5 percent increase in housing starts).
underground භූගත Laying below ground levl or beneath the surface of the ground. For example, an underground cable.
under-voltage අඩු වෝල්ටීයතාවය A condition where the applied voltage drops to 90% of rated voltage, or less, Like a sag, but for a longer period of time: over 2.5 second, or perhaps 1 minute.
uniform ඒකාකාර Remaining the same in all cases.
unijunction transistor, UJT තනි හන්දිය ට්‍රාන්සිස්ටරය This low power transistor is useful in electronic timing, waveshaping and control applications.
uninterruptible power supply, UPS අඛණ්ඩ බල සැපයුම A system designed to automatically provide power, without delay or transients, when the normal power supply is incapable of supplying acceptable power. Some UPSs also filter and/or regulate utility power.
unit impulse ඒකක ආවේගය A function with unit integral area, which is zero everywhere except at zero time where it is infinite.
unit matrix ඒකක න්‍යාසය A square matrix, who has all diagonal elements as one and all off diagonal elements as zero.
unit ramp ඒකක බෑවුම A function which is zero for negative time, and unit slope for positive time.
unit step ඒකක පියවර A function with zero magnitude for negative time and unit magnitude for positive time.
universal resource locator, url විශ්ව සම්පත් ස්ථානගත කිරීම This is the method of addressing on the web. They include the file transfer protocol (ftp) and the hyper text transfer protocol (http).
unserved energy සපයා නැති ශක්තිය The average energy that will be demanded but not served during a specified period due to inadequate available generating capacity.
user පරිශීලක Authority responsible for the use and maintenance of equipment.
utilisation පරිභෝජනය The process of exploiting (using) electrical energy for various purposes.
utility උපයෝගීතාව A regulated entity which exhibits the characteristics of a natural monopoly. For the purposes of electric industry restructuring "utility" refers to the regulated, vertically-integrated electric company. Transmission utility refers to the regulated owner/operator of the transmission system only. Distribution utility refers to the regulated owner/operator of the distribution system which serves retail consumers.
utilization factor උපයෝගීතා සාධකය The ratio of the maximum demand of a system or part of a system to the rated capacity of the system or part of the system.
utltraviolet පාරජම්බුල UV is electromagnetic radiation with wavelength from 10 nm to 400 nm, shorter than that of visible light but longer than X-rays. UV radiation is present in sunlight, and contributes about 10% of the total electromagnetic radiation output from the Sun.
V මුලට TOP
vacuum රික්තය Space in which there is no matter or in which the pressure is very low (partial vacuum). It is a condition well below normal atmospheric pressure and is measured in units of pressure.
vacuum circuit breaker රික්ත පරිපථ කඩනය A circuit breaker where the arc quenching takes place in vacuum medium.
vacuum pump රික්ත පොම්පය A device that removes gas molecules from a sealed volume in order to leave behind a partial vacuum.
validate තහවුරු කිරීම To prove that something is based on truth or fact, or is acceptable.
valley filling නිම්න පිරවීම A form of load management that increases or builds, off-peak loads. This load shape objective is desirable if a utility has surplus capacity in the off-peak hours. If this strategy is combined with time-of-day rates, the average rate for electricity can be lowered.
value අගය Is either the result of a calculation or the magnitude of a variable or constant.
valve කපාටය A device for controlling the passage of fluid or air through a pipe, or current in a device, allowing movement in one direction only.
variable cost විචල්ය වියදම Costs, such as fuel costs, that depend upon the amount of electric energy supplied.
variac (variable autotransformer) වේරියැක් (පරිණාමකය) A variable autotransformer or a single-coil transformer in which two portions of the same coil are used as the primary and the secondary. Variac is in fact a trademark
vector දෛශිකය A quantity having direction as well as magnitude. It is also a list of numbers arranged either in row or column form in matrix analysis.
vector diagram දෛශික රූපසටහන A diagram that depicts the direction and relative magnitude of a vector quantity by a vector arrow.
ventilation සංවාතනය The process of replacing air in a given space to provide high indoor air quality
verification හරිවැරදි බැලීම, සත්‍යාපනය The final proof that establishes something is true.
vernier calipers වනියර කැලිපරය A measuring instrument for making very accurate small linear measurements. It uses two graduated scales: a main scale and a specially graduated auxiliary scale, called the vernier, that slides parallel to the main scale and enables readings to be made to a very small fraction of a division on the main scale.
vertical integration සිරස් ඒකාබද්ධ කිරීම An arrangement whereby the same company owns all the different aspects of making, selling, and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants, transmission system, and distribution lines to provide all aspects of electric service.
very high frequency, VHF ඉතා ඉහළ සංඛ්‍යාතයක් Radio frequencies in the range 30 MHz to 300 MHz.
vibration කම්පනය A mechanical phenomenon of oscillations about an equilibrium point. The oscillations may be periodic or random.
vibration galvanometer කම්පන ගැල්වනෝමීටරය A mirror galvanometer where the natural oscillation frequency of the moving parts is carefully tuned to usually the mains frequency.
viscosity දුස්ස්‍රාවිතාව A quantity expressing the magnitude of internal friction in a fluid, as measured by the force per unit area resisting uniform flow.
viscous damping දුස්ස්‍රාවී පරිමන්දනය Dissipation of energy that occurs when a particle in a vibrating system is resisted by a force the magnitude of which is a constant, independent of displacement and velocity, and the direction of which is opposite to the direction of the velocity of the particle.
visible radiation දෘශ්‍ය විකිරණය Electromagnetic radiation that causes the sensation of sight, or visible light. It has wavelengths between about 380 and 780 nanometres.
visual corona දෘශ්‍ය කොරෝනා (අංශු රශ්මි මාලාව) Visible signs (usually a bluish glow) of the presence of corona, which occurs at a higher electric field than is necessary for the inception of corona.
VLSI, very large scale integration ඉතා විශාල පරිමාණයේ ඒකාබද්ධ කිරීම Process of creating an integrated circuit (IC) by combining thousands of MOS transistors onto a single chip. 10,000 to 99,999 gates per chip.
volatile වාෂ්පශීල A substance that is easily evaporated at normal temperature.
volatile memory වාෂ්පශීලී මතකය Memory requiring electrical power to keep information stored.
volt (V) වෝල්ටය SI unit of electromotive force or voltage, equal to the difference of potential that would carry one ampere of current against one ohm resistance.
volt ampere වෝල්ට් ඇම්පියරය The unit used for the apparent power in an electrical circuit and is equal to the rms product of voltage and current.
voltage වෝල්ටීයතාව Voltage is the electrical potential difference across two points in a circuit and what makes electric charges to move.
voltage bands වෝල්ටීයතා පටි Band I - installations where protection against electric shock is provided under certain conditions by the value of voltage: installations where the voltage is limited for operational reasons (e.g. telecommunications, signalling, bell, control and alarm installations). Extra low voltage (ELV) will normally fall within voltage band I. Band II - Supplies to household, and most commercial and industrial installations. Low voltage (LV) will normally fall within voltage band II. Band II voltages do not exceed 1000 V a.c. rms or 1500 V d.c.
voltage drop වෝල්ටීයතා බැස්ම The loss of voltage between the input to a device and the output from a device due to the internal impedance or resistance of the device.
voltage regulation වෝල්ටීයතා යාමනය A measure of change in the voltage magnitude across the ends of a component, such as a transmission or distribution line.
voltage regulator වෝල්ටීයතා නියාමකය Voltage regulators control the output voltage, eliminating voltage sags and swells in the input voltage that last from 15 milliseconds to one-half second. They are typically relatively inexpensive feedback controlled transformers and the more expensive ferroresonant transformer.
voltage source වෝල්ටීයතා ප්‍රභවය A two-terminal device which can produce a defined voltage independent of the load conditions. An ideal voltage source can maintain the fixed voltage at fixed frequency independent of the output current. Maintains the terminal voltage close to the internal emf.
voltage stabilizer වෝල්ටීයතා ස්ථායීකාරකය An electrical appliance used to limit the voltage fluctuations of a power supply and give a constant voltage to electrical equipment. They also thus protect the equipment from damage due to high voltage pulses.
voltage surge වෝල්ටීයතා සර්ජනය A sudden excessive rise in voltage, with a duration of less than a half-cycle of the normal waveform, which may damages electrical. A surge, or transient, is a subcycle overvoltage.
voltage වෝල්ටීයතාව (විභව අන්තරය) [see potential difference]
voltage, nominal නාමික වෝල්ටියතාව Voltage by which an installation (or part of an installation) is designated. The following ranges of nominal voltage (rms values for a.c.) are defined: Extra low. Normally not exceeding 50 V a.c. or 120 V ripple free d.c., whether between conductors or to Earth. Low. Normally exceeding extra low voltage but not exceeding 1000 V a.c. or 1500 V d.c. between conductors, or 600 V a.c. or 900 V d.c. between conductors and Earth. The actual voltage of the installation may differ from the nominal value by a quantity within normal tolerances.
voltage, reduced ඌනිත වෝල්ටීයතාවය [see Reduced low voltage system]
voltampere (VA) වෝල්ට් ඇම්පියරය The basic unit of Apparent power. The voltamperes of an electric circuit is the mathematical product of the volt and ampere of the circuit. The practical unit of Apparent power is kilovoltampere (kVA).
voltmeter වෝල්ටමානය An instrument for measuring electric potential difference between two points in an electric circuit. They have very high internal resistances so as not to draw any significant current to influence the reading.
volume පරිමාව The quantity of three-dimensional space occupied by a liquid, solid or gas and usually expressed in litre or cubic meter.
W මුලට TOP
Wagner earthing වාග්නර් බිම්ගැන්නුම The Wagner earthing is used for removing the earth capacitance from alternating current bridges. It is an additional voltage divider circuit used to reduces the error which occurs because of stray capacitance.
Wagner earthing වොග්න බිම් ගන්නන A null-balance method of keeping the arms of a bridge at earth potential without directly earthing any part of the bridge. It has an additional voltage divider circuit to reduce the error which occurs because of stray capacitance.
waterproof දියවරන Not allowing water to go through and damage equipment.
watertight ජලපරිරෝධක Closely sealed, fastened, or fitted so that no water enters or passes through.
watt වොටය SI unit of power, equivalent to one joule per second, corresponding to the rate of consumption of energy in an electric circuit where the potential difference is one volt and the current one ampere.
watt (W) වොට් SI unit of power. One watt is equal to a power rate of one joule of work per second of time.
wattmeter වොට් මීටරය A meter for measuring electric power in a given circuit. A good wattmeter should consume negligible power.
wave තරංගය A kind of oscillation that travels through space and matter.
wave front, wavefront තරංග පෙරමුණ The part of a waveform, between the start ad the crest, in time. For fast rising surge waveforms, the wavefront time is defined from start to crest based on two defined points on the leading edge (such as 1.25 times the duration from 10% to 80% of peak.
wave tail, wavetail තරංග කෙළවර The part of a waveform, between the crest and the end, in time. For exponentially decaying surge waveforms, the wavetail time is defined from the crest to decay to half peak.
waveform, waveshape තරංග ආකාරය, තරංග හැඩය The graphic representation of the variation of a quantity (such as voltage) as a function of some variable, usually time.
wavelet තරංගිකාව A wave-like oscillation with an amplitude that begins at zero, increases, and then decreases back to zero.
weather කාලගුණකය The state of the atmosphere at a particular place and time with regard to parameters such as temperature, humidity, cloudiness, sunshine, wind and rain.
weber (Wb) වේබරය SI unit of magnetic flux. One weber is equal to the magnetic flux which, linking a circuit of one turn, would produce in it an electromotive force of 1 V if it were reduced to zero at a uniform rate of 1 s.
weight බර, භාරය The weight of an object is the force of gravity on the object and may be defined as the product of mass and the acceleration due to gravity,
weighting බර තැබීම The adjustment made in order to take account of special circumstances or importance of individual items.
welding වෙල්ඩිම Joining together of metal parts by heating the surfaces to the point of melting with a blowtorch, electric arc, or other means.
Weston standard cadmium cell වෙස්ටන් ප්‍රමිති කැඩ්මියම් කෝෂය A primary cell used as a standard of emf, producing 1.018636 volt and consisting of a mercury anode and a cadmium amalgam cathode in an electrolyte of saturated cadmium sulphate.
wet and dry bulb thermometer තෙත් වියළි බල්බ උෂ්ණත්වමානය A type of hygrometer consisting of two thermometers, one of which has a dry bulb and the other a bulb that is kept moist and ventilated. The difference between the readings of the thermometers gives an indication of atmospheric humidity.
Wheatstone bridge වීට්ස්ටන් සේතුව A electrical circuit used to measure an unknown electrical resistance by balancing a four-arm bridge circuit, one arm of which is the unknown component and another arm a standard variable resistor. Balance is obtained by null deflection when the ratio of the adjacent arms are equal.
white light සුදු ආලෝකය Is light, such as sunlight, that contains all the colors of the visible spectrum in roughly equal amounts.
white noise සුදු ඝෝෂාව A random signal (noise)having equal intensities at all frequencies, giving it a constant power spectral density.
wholesale bulk power තොග තොග ජවය Very large electric sales for resale from generation sources to wholesale market participants and electricity marketers and brokers.
wholesale competition තොග තරඟය A system whereby a distributor of power would have the option to buy its power from a variety of power producers, and the power producers would be able to compete to sell their power to a variety of distribution companies.
wholesale power market තොග බලශක්ති වෙළඳපොල The purchase and sale of electricity from generators to resellers (who sell to retail consumers) along with the ancillary services needed to maintain reliability and power quality at the transmission level.
Wimshurst machine විම්හස්ට් යන්ත්‍රය A device that uses electrostatic induction to produce an electric potential between two electrodes.
wind energy conversion සුළං බලශක්ති පරිවර්තනය A process that uses energy from the wind and converts it into mechanical energy and then electricity.
winding එතුම One or more turns of wire that forms a continuous coil through which an electric current can pass, as used in transformers and generators.
windmill සුළං යත A structure with vanes or blades that turn in the wind to generate power (originally to grind corn into flour).
wireless නිස්තර Transfer of information or power between two or more points that are not connected by an electrical conductor.
wiring කම්බි පථය, කම්බි ඈදීම A system of wires providing electric circuits for a device or building.
wiring diagram කම්බි ඇදුම් සටහන A simple visual representation of the physical connections and physical layout of an electrical system or circuit. It shows how the electrical wires are interconnected and can also show where fixtures and components may be connected to the system.
wiring system රැහැන් පද්ධතිය An assembly made up of cable or busbars and parts which secure and, if necessary, enclose the cable or busbars.
word පදය A group of bits representing a complete piece of digital information.
work bench කාර්ය මේසය A strong table on which work, especially of mechanics, machinists, and carpenters is performed.
working temperature ක්‍රියානුරූප උෂ්ණත්වය The temperature at which an electrical or mechanical device normally operates.
working voltage ක්‍රියානුරූප වෝල්ටීයතාව The highest possible effective value of voltage across insulation when the product is operating at it rated voltage.
world wide web, www විශ්ව විසිරි වියමන An information system on the Internet which allows documents to be connected to other documents by hypertext links, enabling the user to search for information by moving from one document to another.
wound rotor එතූ බ‍්‍රමකය Rotor of an induction motor provided with a three-phase winding in the rotor.
write ලියනවා The process of storing information in a memory.
wye connection වයි සම්බන්ධතාවය [see star connection]
X මුලට TOP
x ray, x-ray X කිරණ A picture taken of the inside of something using electromagnetic radiation of high energy and very short wavelength, which is able to pass through many materials opaque to light. Electromagnetic radiations of the same type as light, but of much shorter wave-length, in the range of 5 nm to 6 nm produced when cathode rays strike a material object.
x-y plot x-y ප්‍රස්ථාරය A graphic representation of the relationship of the X signal, which controls the horizontal position of the beam in time, and the Y signal, which controls the vertical position of the beam in time.
Y මුලට TOP
yocto (y) යොක්ටො Decimal sub-multiple prefix corresponding to 10-24
yoke දණ්ඩ, විය The horizontal portion of the transformer magnetic core, where there is no winding, is known as the yoke. The vertical portion on which the coil is wound is called the limb.
yotta (Y) යොට්ටා Decimal multiple prefix corresponding to 1024
Young's modulus යං මාපාංකය A measure of elasticity, equal to the ratio of the stress acting on a substance to the strain produced.
Z මුලට TOP
zener diode සේනර් දියෝඩය, සීනර් දියෝඩ A special kind of diode which permits current to flow in the forward direction as normal, but also allows it to flow in the reverse direction when the voltage is above a limiting voltage known as the Zener voltage. A junction diode designed to operate in the reverse bias region.
zepto (z) සේප්ටො Decimal sub-multiple prefix corresponding to 10-21
zero බින්දුව, ශුන්‍යය Zero is the integer denoted 0 that, when used as a counting number has a null value. It is the only integer or real number that is neither negative nor positive.
zero sequence ශුන්‍ය අනුක්‍රමය A balanced set of three phase components which have the same magnitude and the same phase angle, and hence hence no sequence. The frequency is of course the same as the original unbalanced three phase system.
zetta (Z) සේටටා Decimal multiple prefix corresponding to 1021
zone කලාපය An area or stretch having a particular characteristic or subject to particular restrictions.
z-trace z-හෝඩුවාව . The signal in an oscilloscope that controls the electron-beam brightness as the trace is formed.

  © Copyright reserved by the author Professor J R Lucas, December 2001. (Last edited 4 December 2019)