KIA K3 2012
Honda CRV 2012
Car Accessories
HID Xenon Kit Daytime Running Light Projector Lens Car View Camera Parking Sensor Car DVD Player

Q:How the BALLAST work?

A:HID headlamp bulbs do not run on low-voltage DC current, so they require aballast with either an internal or external ignitor. The ballast controls the current to the bulb. The ignition and ballast operation proceeds in three stages:

1   Ignition: ahigh voltage pulse is used to produce a spark – in a manner similar to aspark plug – which ionises the Xenon gas, creating a conducting tunnel between the tungsten electrodes. Electrical resistance is reduced within the tunnel, and current flows between the electrodes.

2        Initial phase: the bulb is driven with controlled overload. Because the arc is operated at high power, the temperature in the capsule rises quickly. The metallic salts vaporise, and the arc is intensified and madespectrally more complete. The resistance between the electrodes also falls; the electronic ballast control gear registers this and automatically switches to continuous operation.

3        Continuous operation: all metal salts are in the vapor phase, the arc has attained its stable shape, and theluminous efficacy has attained its nominal value. The ballast now supplies stable electrical power so the arc will not flicker. Stable operating voltage is 85. The frequency of the square-wave alternating current is typically 400hertz or higher.


2011-08-02 02:46:19