These are a range of lighting terminology used in the industry to discuss and describe both general and LED lighting.
ANSI Codes: These are 3-letter codes assigned by the American National
Standards Institute. They provide a system of assuring mechanical and electrical interchangeability among similarly coded lamps from various
manufacturers.
Average Rated Life: The number of hours at which half of a large group of product samples fail under standard test conditions. Rated life is a median value; any lamp or group of lamps may vary from the published rated life.
Adaptation: The mechanism by which the human eye adapts to changes in light
levels to distinguish objects in the background.
Cap: The removable or hinged rear cover of some luminaires that contains
the lamp socket, lamp and power cord.
Capacitor: A device used in electric circuitry to temporarily store electrical charge in the form of an electrostatic field. In lighting, a capacitor is used to smooth out alternating current from the power supply.
Colour Shift: A terms used to described the process whereby lamps or LEDs change colour over their lifetime, often as a result of heat dissipation.
Electrical Current: Is the flow of electrons or negatively charged particles. Current is measure in units called amperes. The number of amperes in a wire relates to how many electrons flow across a wire per second.
Light Pollution: Refers to excess light given off by signs, houses, building and other lights, which is wasted light or an unnecessary use of energy.
Load Shedding: The practice of turning off electrical devices during peak energy
demand hours to reduce building energy use.
Light Trespass (Spill Light): Light that is not aimed properly or shielded effectively can spill out at into areas that don’t want it: it can be directed towards drivers, pedestrians or neighbors. It is distracting and can be disabling.
Luminaire: A complete lighting unit consisting of a lamp (or lamps) and ballast (or
ballasts) as required, together with the parts designed to distribute the light, position and protect the lamps, and connect them to the power supply. A luminaire is often referred to as a fixture.
Rated Life Output: The sum of the initial rated lamp lumens of the lamp(s) that were supplied with the luminaire.
Rated Lamp Life: The number of hours at which half of a group of product samples fail. The rated life is a median value of life expectancy; any lamp or group of lamps may vary from the published rated life. Rated life is based on
standard test conditions.
Rated Lumen: Also referred to as rated light output from lamp in lumens. Lumen
refers to a unit measurement of the rate at which a lamp produces light. A lamp’s light output rating expresses the total amount of light emitted in all directions per unit time. Manufacturers rate their lamps’ initial light output after 100 hours of operation.
Reflector: A metal or glass apparatus, usually curved in some manner, used in
most luminaires for the purpose of directing light rays from a light
source.
Useful Life: The amount of light a lighting fixture delivers in an application, minus
any wasted light.