HID Head Lights - High Intensity Discharge LightsPosted in Features on September 1, 2002
10 Hot Bolt-Ons
Less power, brighter light - that's the concept behind High Intensity Discharge driving lights and headlights. The workings of an HID light are complex and would require many pages for a thorough explanation, but we can offer an overview. A compound of highly pressurized xenon gas, mercury, metal halides (salt), sodium, and other gases is contained within a small glass tube (the arc tube or bulb, usually rated at 35 watts). Also in the tube is a pair of tungsten-tipped electrodes, mounted a few millimeters apart. A high-voltage transformer takes the battery's 12 volts and steps it up to 1,000 volts. The high voltage is sent to the electrodes, causing an arc, which ignites the gases and elements inside the arc tube, causing them to burn at a temperature of 4,000 degrees Kelvin, which is comparable to daylight. After the arc ignites the gases, an electrical ballast steps down the voltage while the light warms, then gradually increases electrical power to a level required to consistently power a fully warm HID light. The result of all this high-tech electrickery is a brilliant, clean, blindingly powerful light source that's as close to true daylight in color as a man-made light can be. HID lights certainly aren't what anyone would call a low-buck or even medium-buck item, but once you've seen the true white light produced by an HID light, every other type of driving light may seem inadequate. Don't say we didn't warn you.