# EEVblog Electronics Community Forum

## Electronics => Beginners => Topic started by: firewalker on September 02, 2016, 04:54:55 am

Title: Car Xenon light drivers, DC/AC?
Post by: firewalker on September 02, 2016, 04:54:55 am
The high voltage output of car Xenon lights is usually "DC" or AC?

(https://i.imgur.com/Ku5XCjzs.jpg) (https://i.imgur.com/Ku5XCjz.jpg)

Alexander.
Title: Re: Car Xenon light drivers, DC/AC?
Post by: mikeselectricstuff on September 02, 2016, 05:09:12 am
Discharge lamps are typically dc, with a high voltage impulse to strike them
Title: Re: Car Xenon light drivers, DC/AC?
Post by: firewalker on September 02, 2016, 05:20:37 am
Can someone use it as a high voltage supply (like people use neon lamp drivers)? Or the continuous high voltage output (arching) will destroy it?

Alexander.
Title: Re: Car Xenon light drivers, DC/AC?
Post by: bktemp on September 02, 2016, 05:58:14 am
The burning voltage of those discharge lamps is somewhere between 30-100V. I wouldn't call this high voltage. The only high voltage is the striking voltage (>10kV for striking a hot lamp), but this lasts only a couple of microseconds.
The lamp driver will probably shut down if it does not see the correct load, because those lamps are often driven using constant power regulation.
Title: Re: Car Xenon light drivers, DC/AC?
Post by: firewalker on September 02, 2016, 06:03:11 am
I have half a dozen of those. I will test one tomorrow. I will  leave arching away in air. From the sound of the output, the pulse should be in the range of  hundreds of hertz.

Alexander.
Title: Re: Car Xenon light drivers, DC/AC?
Post by: bktemp on September 02, 2016, 06:12:23 am
The sound you can hear is the repetition rate of the ignition pulse, but each pulse is very short and has not much power. The actual power delivered to the lamp is the low voltage DC output, after the arc has ignited.