Cold Cathode Light

Thread Starter


Joined Apr 19, 2010
My Cold Cathode light went out of my laptop, so I replaced it. Well that wasn't the problem, so I am now replacing the converter for the Cold Cathode Light.

I am wanting to test the old light that I got out but I have a few questions. I have looked on the internet for the answers but I haven't really found direct answers to my questions.

First of all, Cold Cathode lights in laptops--do they run off of AC or DC? I am replacing the converter, but I don't know if it is a converter that turns DC into AC or that converts the DC into a higher voltage. I have found out that Cold Cathode lights take an extreme amount of voltage to power them--read in some places that they can be 600 to 1800 volts, but that the mA is extremely low, around 5 or so. Does that sound correct?


Joined Sep 21, 2010
Hi , This is what i use to check cold cathode tubes in LCD displays, it runs of 12V dc. It was salvaged from an old LCD display. The tube is supplied with HV high freq AC.