Outdoor Lighting Glossary

Come across a lighting word you aren't sure of? Completely new to the world of lighting? We feel your pain! Here you will find a collection of terms and concepts that should help to make your life easier.

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Select the first letter of the word from the list above to jump to appropriate section of the glossary.

Filament - Wire element, often coiled, in a lamp that becomes incandescent and emits light when heated by an electric current.

Fixture - Informal substitute term for luminaire, especially a luminaire without the lamps.

Flicker - Variation in light intensity due to 60 Hz operation. Can cause eyestrain and fatigue due to stroboscopic effects.

Floodlighting - A system designed for lighting a scene or object to a luminance greater than its surroundings. It may be for utility, advertising or decorative purposes

Fluorescence - Light resulting from the action of ultraviolet or other forms of energy on phosphors. Fluorescence occurs only while energy is being absorbed by the fluorescing material. ( Time scale less than 10-8 seconds.)

Fluorescent Lamp - A low-pressure mercury electric-discharge lamp in which a fluorescing coating (phosphor) transforms some of the ultraviolet energy generated by the discharge into light.

Flux - Continuous flow of luminous energy

Foot Lambert (fl) - A unit of luminance of a perfectly diffusing surface emitting or reflecting light at the rate of one lumen per square foot.

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

Fuse - Replaceable safety device to prevent excess current flow.