Active Cooling:

A cooling process that uses power for cooling components such as fans to actively exhaust heat from components.


The preferred LED (Light Emitting Diode) chip technology containing Aluminum, Indium, Gallium, and Phosphorous to produce red, orange and amber-colors.

Average Rated Life:

An average rating, in hours, indicating when a percentage of a large group of lamps have failed, when operated at nominal lamp voltage and current. The life of an LED is defined as the operating time in hours for the lamp to reach L70 which designates 70% lumen maintenance (or 30% reduction in initial light output). Every lamp type has a unique mortality curve that depicts its average rated life.

Beam Angle:

The angle between two directions for which intensity(candle power) is 50% of the maximum intensity as measured in a plane through the nominal beam centreline.


The grouping of LEDs (from production) according to specifications, such as light output, color, and voltage so that LEDs of similar light performance are grouped.

A horseshoe shaped line connecting the chromaticities of the spectrum of colors. (See Color Definition, Chroma)


A term used for the board or “light engine” to which the LEDs are applied. The chip or “light engine” is a circuitry board for the LED.


Describes the degree of departure from gray of the same lightness and increasing color (e.g. red, redder, pure red)

Color Spectrum:

All wavelengths perceived by human sight, usually measured in nanometers (nm)

Color temperature:

The description used to describe the effect of heating an object until it glows incandescently, the emitted radiation, and apparent color, changes proportional to the temperature; easily envisioned when considering hot metal in a forget that glows red, then orange, and then white as the temperature increases. Term and symbol (K) used to indicate the comparative color appearance of a light source when compared to a theoretical blackbody.

CRI or Color Rendering Index:

The calculated rendered color of an object.

The higher the CRI (based upon a 0-100 scale), the more natural the colors appear. Natural outdoor light has a CRI of 100


Heart of the LED. The light emitting semiconductor.


An optical element used to mix light rays to improve uniformity.


A two-terminal semiconductor device having a p-n (positive-negative) junction which allows energy travel in one direction.


A self-contained power supply that has outputs which match the electrical characteristics of the lamp. It is similar to a ballast and is used to power illumination sources.

Efficacy - (Luminous Efficacy):

The light output of a light source divided by the total electrical power input to that source, expressed in lumens per watt (lm/W)


A footcandle is one lumen per square foot.

Heat Sink:

An object that conducts or convects heat away from an LED lamp.


The preferred LED (Light Emitting Diode) semiconductor technology containing Indium, Gallium, and Nitrogen to produce green, blue and white-colored LED light sources.


A Light Emitting Diode (LED) is a solid-state semiconductor device that converts electrical energy directly into light. On its most basic level, the semiconductor is comprised of two regions. The p-region contains positive electrical charges while the n-region contains negative electrical charges. When voltage is applied and current begins to flow, the electrons move across the n region into the p region. The process of an electron moving through the p-n junction releases energy. The dispersion of this energy produces photons with visible wavelengths.

LED Array:

An arrangement of LEDs onto a printed circuit board or other surface that is capable of producing light when powered.


Lumen (lm) is a measure of luminous flux or quantity of light emitted by a source.

Lumen maintenance:

The remaining flux percentage at the rated life of a light source.

Lumen Maintenance Curve:

A graph comparing the loss of light output against the time the light source is used.


A lighting fixture complete with installed lamps and other accessories.

Luminaire Efficacy:

Measures the efficacy of the complete luminaire, or fixture, taking into account the optics, thermal design, and other design factors that impact efficacy. It is calculated by measuring the total light output of a luminaire, divided by the amount of power drawn by that luminaire. It is expressed in lumens per watt (lm/W).


A lux is one lumen per square meter; differs from foot-candle by about a factor of 10.


LED testing that measures total luminous flux, luminous intensity of distribution, electrical power, efficacy, and color characteristics.


LED testing that measures the lifespan of LEDS by measuring the amount of lumen depreciation.

Passive Cooling:

A method of cooling that takes place without the use of power.


The retrofit LED is a bulb or trim that is designed to convert an existing line voltage luminaire housing to an energy efficient LED luminaire.


Surface Mount Device LEDs. LEDs are soldered to the surface of the PCB(Printed Circuit Board)

Solid-State Lighting (SSL):

Lighting that uses LEDs to emit light from a solid object -a semiconductor- rather than from vacuums or gas tubes used in incandescent and fluorescent lighting. Solid-State Lighting does not contain moving parts that can break or shatter, potentially contaminating the environment.

Thermal management:

Controlling the operating temperature of the product through design, examples includes heat sinks and improved airflow.

Thermal resistance (C/W):  

A measure of the heat transfer capacity of the LED. Lower resistance is preferred.

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