etetool.gif (3468 bytes)"Basic Lighting Definitions" 

Here is a list of basic definitions , but some can be easily misconstrued.

Accent Lighting Cold Cathode Lamps Hot Cathode Lamps Mercury Lamps
Ambient Temperature Cove Lighting Illumination Metal Halide Lamps
Andonizing Diffuser Incandescent Filament Reflector
Asymmetric Foot-candle Infrared Lamp Refractor
Ballast Footlambert Kilowatt Hour Symmetric
Candlepower H.I.D. Lamps Louver Troffer
Coefficient of Utilization High Pressure Sodium Lumen Tungsten-Halogen

Definitions (in alphabetical order):

Accent Lighting - Directional lighting to emphasize a particular object or draw attention to a part of the field of view.

Ambient Temperature - Temperature surrounding a lamp, luminaire,etc.

Andonizing - Any electrolytic or chemical process by which a protective or decorative film is released on a metal surface.

Asymmetric - Unequal distribution about one or more axes.

Ballast - An auxiliary electrical device for fluorescent and other discharge light sources.

Candlepower (or Candela) - Basic unit for measuring luminous intensity from a light source in a given direction.

Coefficient of Utilization - The amount of light (lumens) delivered in a workplane as a percent of the rated lumens of the lamp.

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Cold Cathode Lamp - An electric-discharge lamp whose mode of operation is that of a glow discharge (Neon Lights).

Cove Lighting - Distributes light over the ceiling and upper wall.

Diffuser - A device to redirect or scatter the light from a source.

Footcandle (fc) - The unit of illumination when the foot is taken as the unit of length. It is the illumination on a surface one square foot in area on which there is a uniformly distributed flux of one lumen.

Footlambert (fl) - A unit of luminance (photometric brightness) equal to one candela per square foot.

High Intensity Discharge Lamps (H.I.D.) - A general group of lamps consisting of mercury, metal halide, high pressure sodium, and low pressure sodium lamps.

High-pressure Sodium Lamps - A sodium vapor in which the partial pressure of the vapor during operation is the order of 0.1 atmospheres.

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Hot Cathode Lamp - An electrical discharge lamp whose mode of operation is that of an arc discharge.

Illumination - The density of the light flow incident on a surface.

Infrared Lamp - An electrical device that emits infrared rays - invisible rays just beyond red in the visible spectrum.

Incandescent Filament Lamp - A lamp in which light is produced by a filament heated to incandescence by an electrical current.

Kilowatt Hour (KWH) - The work performed by one kilowatt of electric power in one hour. The unit on which the price of electrical energy is based.

Louver - A series of baffles used to shield a source from view at certain angles or to absorb unwanted light.

Lumen - The derived SI unit for luminous flux; unit measure of light.

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Mercury Lamps - An electric discharge lamp in which the major portion of the radiation is produced by the excitation of mercury atoms.

Metal Halide Lamps - A discharge lamp in which the light is produced by the radiation from the mixture of metallic vapor and the products of disassociation.

Reflector - A device used to redirect the light flow from a source by bouncing it off the surface.

Refractor - A device used to redirect the light flow from a source, primarily by bending the wave light.

Symmetric - Equal distribution about one or more axes.

Troffer - A recessed lighting unit, installed with the opening flush with the ceiling.

Tungsten-Halogen Lamp - A gas filled tungsten incandescent lamp containing proportion of halogens.

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If there is anything you would like to add or if you have any comments please feel free to email E.T.E. at

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