What are HID's?
The best way to describe an HID headlight is to compare it to a more conventional halogen headlight. A halogen bulb consists of a wire filament surrounded by an inert gas. When electrical current is applied to the filament, it glows brightly to produce light. Contrast that with an HID bulb which has no filament, but instead consists of xenon gas, mercury, and metal halide salts. The xenon gas is ignited by an arc of high-voltage current and glows brightly. Also, the high voltage is supplied by a ballast, so in these respects it is like a fluorescent light. HID's are original equipment generally found on luxury and exotic cars but are progressively finding their way into the mainstream. For example, the 2004 Mazda 3s at ~$17k will include HID's.
The best way to describe an HID headlight is to compare it to a more conventional halogen headlight. A halogen bulb consists of a wire filament surrounded by an inert gas. When electrical current is applied to the filament, it glows brightly to produce light. Contrast that with an HID bulb which has no filament, but instead consists of xenon gas, mercury, and metal halide salts. The xenon gas is ignited by an arc of high-voltage current and glows brightly. Also, the high voltage is supplied by a ballast, so in these respects it is like a fluorescent light. HID's are original equipment generally found on luxury and exotic cars but are progressively finding their way into the mainstream. For example, the 2004 Mazda 3s at ~$17k will include HID's.
Top is Halogen Filament.
Bottom is an HID Conversion Kit
Bottom is an HID Conversion Kit