Understanding HID Lighting

High Intensity Discharge (HID) lighting technology replaces the filament of the light bulb with a capsule of gas. The light is emitted from an arc discharge between two closely spaced electrodes hermetically sealed inside a small quartz glass tubular envelope capsule. To operate, they require ballasts, which supply proper voltage and control current. The amount of light produced is greater than a standard halogen bulb, while consuming less power, and more closely approximating the color temperature of natural daylight.

In all High Intensity Discharge lamps, light is produced by passing a current through a metal vapor. Free electrons colliding with an atom in the vapor momentarily knock an electron into a higher orbit of the atom. When the displaced electron falls back to its former level, a quantum of radiation is emitted. The wavelength of radiation depends on the energy zone of the disturbed electron and on the type of metal vapor used in the arc tube.

Although it produces 5% of its output when first ignited, the HID light requires a few seconds (usually 15-20) to come up to full output. Also, if power to the lamp is lost or turned off, the arc tube must cool to a given temperature before the arc can be re-struck and light produced. Our HID lights only require a brief (15-30 second) cooling period before they can be re-lit.