What is an electronic ballast?
In a fluorescent or High Intensity Discharge (HID) lighting system, the electrical ballast provides the initial voltage required to start the lighting bulb. It also regulates the electrical current going to the light once it is lit. Without a ballast, lamps draw too much power which can cause them to burn out prematurely.
Xenon electronic ballasts
In order to be safe and effective for car headlight use, Xenon headlight bulbs must be able to light up quickly, making the quality and reliability of the electronic ballast extremely important.
The Xenon ballast must also precisely regulate the electric current in the lighting system. Too much power and the headlamp will burn out prematurely, too little power and the headlight can be damaged, causing uneven lighting and possible cracks in the arc inside the bulb.
Electronic ballasts also act as DC to AC converters. As Xenon lamps cannot run on a DC current, and most available power sources for headlights are DC, the ballast must first convert this to an AC current.
Twenty thousand volts (20kV) are emitted by the electrical ballast and the ignitor during the Xenon lamp start up, so it is essential to power off the system for any lighting maintenance procedures. While some vehicles may disengage the lighting system through key removal or door closing, it is recommended that only a disconnected battery can totally secure operators from a 20kV discharge.