Xenon bulbs are HID (high-intensity discharge) electric lights used mainly to make exceptionally powerful headlights, although their applications have become considerably more varied in recent times. They are called xenon bulbs due to the fact that they make use of a noble gas called xenon in order to maximize their light output. Unlike incandescent bulbs, xenon bulbs do not make use of a filament to produce light, but instead rely on a form of induction, where a very bright arc of electricity is maintained between a pair of electrodes. Due to their lack of a filament, xenon bulbs rarely tend to fail, and can easily outlast their incandescent counterparts by years.
BMW was the first car manufacturer to include xenon bulbs as part of the factory specifications of certain models. BMW cars with xenon lamps first entered the market in 1993 and took it by storm. Xenon bulbs are held in high regard among car enthusiasts both due to their quality and intensity.
One of the main strengths of xenon bulbs is their uniform intensity, sharply illuminating anything they shine on. The light produced by incandescent bulbs tends to become diffused around the edges of the projected field of light, but xenon lamps illuminate everything in their field of projection with equal strength. Another advantage of using xenon bulbs in car headlights is that they also emit ultraviolet lights, which cause reflective road signs to shine vividly, making them significantly more visible to drivers on dark roads.
Halogen bulbs are bright, but xenon bulbs are even brighter, and when in high beam mode, they can temporarily blind any driver who happens to be facing them. Using xenon HID bulbs in high beam mode is not recommended, since they can stun oncoming traffic and cause terrible accidents. Many manufacturers who equip certain models of their cars with xenon bulbs, such as Mercedes-Benz, make use of a special self-leveling technology with their headlights, allowing the headlights to automatically raise or lower themselves by making use of an array of proximity sensors. Certain models of cars, such as Infiniti's Q45, let their drivers manually adjust the height of the headlight in their cars, but this is not a recommended approach. It contains ample room for errors which can be made by a careless driver, and may result in the loss of life and limb.
Xenon bulbs emit a light so intensely white that it almost seems to be blue. However, you should not suppose that all the cars you see with bluish-white headlights are equipped with xenon bulbs. Many aftermarket companies manufacture conventional headlight bulbs and accessory lights with blue tinting in order to achieve an effect similar to that of xenon lamps, but they are in reality nothing more than traditional incandescent bulbs, fitted with blue glass instead of clear glass. While some of these incandescent lamps do use xenon, they use traditional filament technology, not the induction-based brilliance of true xenon bulbs.
Xenon bulbs operate on very high voltage levels, requiring more than 10,000 volts alone to merely allow the induction to take place, and approximately a hundred volts after that hurdle. In order to provide such a massive potential difference, special transformers called ballasts need to be installed in the cars. The ballasts are often sold together with the xenon bulbs in convenient packages. Xenon bulb assemblies, although expensive, also have another advantage – they are much lighter and smaller, allowing more innovation on the part of automobile manufacturers.
Xenon HID bulbs are seeing more and more popularity, and car-lovers are moving toward using xenon bulbs in their headlights instead of traditional incandescent headlights for their superior performance.