A dimming Zone or Channel set for on/off control only.

Control that uses Passive Infrared or Ultrasonic detection to sense whether someone is present or not and to turn on or off appropriately. Automatic On sensors turn lights on when presence is sensed; Manual On sensors require you to press a switch. Both types turn lights off automatically when they no longer sense you.

Milky, translucent glass produced by adding ingredients to clear glass; used for diffusing light.

Positive-Negative junction. The active region of a light emitting diode, where light is generated.

Parabolic Aluminized Reflector Lamp. Constructed of hard glass, with a separate back reflector and front lens that are fused together. PAR lamps may be line or low voltage and can be used unprotected outdoors. Their beam patterns often have an uneven field.

A grid of parabolic-shaped reflector blades, either formed aluminum or molded, aluminized plastic, providing a highly efficient light shield in a recessed fluorescent troffer.

Reflector with parabolic contour, which reflects light emanating from the reflector’s focal point into a beam of parallel rays. Used in PAR lamps and many architectural fixtures.

A detector that senses small movements in your thermal image; not “fooled” by wind or other false signals but requires a clear line of sight. See Ultrasonic.

Fixture suspended from the ceiling on cable, chain or stem. Pendant is also a term for a stem. Pendant Track is suspended on stems.

In dimming, the portion of the alternating current that is switched. Forward phase (or leading edge) dimmers are used for incandescent and magnetic low voltage loads. Reverse phase (or trailing edge) dimmers are used for electronic low voltage and some LED loads.