A part of every fluorescent lamp fixture. It is a circuit that controls the rate of flow of electrical current through a fluorescent lamp. Also used for mercury vapor, sodium vapor and other HID sources. A measurement of beam intensity from reflector lamps as opposed to overall lumens of non-reflector lamps. The darkening of an incandescent lamp caused by small particles of tungsten that evaporate from the filament and deposit on the bulb as the filament burns.
Candlepower is a measurement of light intensity.
It is used as a measurement of beam intensity at various angles from reflector lamps or fixtures. A cathode is an electrode that emits or gives off electrons - the type of electrode in a fluorescent lamp. A rating method by which fluorescent, or any other light source, is evaluated according to its ability to impart color to colored objects, with natural outdoor light having a CRI of 100. Cool White has a CRI of 62, Vita-Lite has a CRI of 91. All the radiant energy wave lengths that make human sight possible.