HID shaped light bulbs •
Compared to fluorescent and incandescent lamps, HID lamps produce a large quantity of light from a relatively small bulb. •
HID lamps produce light by striking an electrical arc across tungsten electrodes housed inside a specially designed inner glass tube. •
This tube is filled with both gas and metals. The gas aids in the starting of the lamps. •
Then, the metals produce the light once they are heated to a point of evaporation. •
Standard high-pressure sodium lamps have the highest efficacy of all HID lamps, but they produce a yellowish light. •
High Pressure Sodium (HPS), Metal Halide, Mercury Vapor and Self-Ballasted Mercury Lamps are all high intensity discharge lamps (HID).