HIGH-INTENSITY DISCHARGE (HID) LAMPS

High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium, low-pressure sodium and less common, xenon short-arc lamps.

The light-producing element of these lamp types is a well-stabilized arc discharge contained within a refractory envelope (arc tube) with wall loading in excess of 3 W/cm2 (19.4 W/in.2).

Compared to fluorescent and incandescent lamps, HID lamps produce a much larger quantity of light in a relatively small package.