Ampere (A)

A measure of electrical current; it is related to voltage and power as follow. Current(A)=Power(W)/Voltage(V)

Average rate life

The medium time it takes for a lamp to burn out.


An auxiliary piece of equipment designed to start and to properly control the flow of power.

Beam Angle*

The angular dimension of the cone of light encompassing the central part of the beam out to the angle where intensity is 50% of the maximum.

Candela (cd)

The international unit(S1) of luminous intensity.

Color Rendering*


Color Rendering Index (CRI)*


Color temperature*

The intrinsic color of the light warmth or coolness emitted by a lamp. It is measured in degrees kelvin(k)

Compact Fluorecent Lamp*

The general term applied to families of compact size fluorescent lamps.

Control Gear

An integrate box include ballast, starter or igniter for use in discharge lamps.

Current (I)

The flow of change is called the current and it is the reate of flow of electrons pass through a particular point in a circuit. The unit for current is Ampere(A)

Electronic Ballast

A ballast with high frequency operation, typically ranging 25-35KHz. The benefits are: increased lamp efficacy, reduced ballast losses.

Emergency Power Pack

A backup battery which supply electricity for the lamp when the main power fails to operate.

Field Angle*

The angular dimension of the cone of light encompassing the central part of the beam out to the angle where intensity is 10% of the maximum.

Flicker free

A type of fluorescent lamp-ballast circuit designed to start the lamps as soon as the power is applied.

Fluorescent Lamp*

A high efficiency lamp utilizing an electric discharge through low pressure mercury vapor to produce ultraviolet(uv) energy for phosphor materials transform to visible light.

General Lighting Service Lamps*

A light source which generates light utilizing a thin filament wire heated to white heat by an electric current passing through it, also called incandescent lamps.

High Intensity Discharge Lamps (HID)*

A general term for mercury vapour, metal halide and high pressure sodium lamps. HID lamps contain gases and metal salts operating at relatively high pressures and temperatures.


refer fundamental theory

Incandescent Lamps

See General Lighting Service Lamps.


Radiant energy which can be seen or sensed by Human


The international unit(S1) of luminous flux or quantity of light


refer fundamental theory

Luminous Efficacy

The light output of a light source divided by the total power input to that source. It is expressed in lumens per watt.

Luminous Flux

refer fundamental theory

Luminous Intensity

refer fundamental theory

Lux (lx)

The international unit(S1) of illuminance. One lux is equal to one lumen per square meter.

Power Factor (PF)

A measure of the phase difference between voltage and current on alternating current circuits. Power factor can range from 0 to 1.0 with 1.0 being ideal.

Power (P)

The rate of using or supplying energy the unit of power is watt(W)


A device used to transfer electric energy, which convert the voltages to suof for use is lamp bulb.

Tungsten halogen Lamp*

A high pressure incandescent lamps containing halogen gases which allow the filaments to be operated at higher temperatures and efficacies.


A ratio of miniumum illuminance to maximum illuminance. It is largely determined by the luminaire light distribution and the spacing between them

Visible Light Spectrum

A portion of the electronagnetic spectrum with wave lengths between 400(violet) and 700(red) nanometers.

Voltage (V)

A measurement of the electronmotive force in an electrical circuit or device expressed in volts(V).

Watt (W)

A unit of electrical power. Lamps are rated in watts to indicate their power consumption. Power consumed over time equals the electrical energy used.