Wiring and switches that permit you to create several levels of illumination, mostly used with non-dimmed fluorescent.

Dimming system that creates several different settings (or scenes) for the lights in a room, generally using a push-button keypad.

Straight down below a fixture; used in photometry and designated as 0 degrees.

One billionth of a meter; the wavelengths of light range from 380 to 780 nanometers.

Sets of standards for wiring practice and the electrical devices used to implement them. The NEC requirements are widely followed by local jurisdictions, whose authority governs. The NEC is a private enterprise, not a Federal regulation!

National Electrical Manufacturers Association, which includes the lamp, electrical device, and larger fixture manufacturers. NEMA develops consensus ratings and designations for various products mostly commercial and industrial.

Incandescent lamp with neodymium coating on the inside of the bulb. The neodymium absorbs just yellow light and so makes the light emitted from the lamp seem brighter and whiter. Other coatings can have the same effect.

Low-pressure arc discharge lamps that operate at high voltage, similar to cold cathode.

A system of dimming controls that are wired and programmed to respond together, usually to link controls in several rooms.

Part of the circuit that carries the current “back” and completes the circuit. Compare to a “hot” or “switch” leg of the circuit.