On Jun 4, 0:52, Tony Duell wrote: [useful stuff] Most resistors are rated for a 500V or 1kV rather than EHT, so there is a small risk that they'll break down or flash over. Better to use two or more in series if you can. It's also worth pointing out that even 1mA at 15kV is a fair wattage -- another reason to use more than one resistor. A large colour CRT might have a 25kV supply. Of course, as Tony points out, usually the CRT will discharge when switched off. But if it doesn't, that's just when you don't want to find out the limitations of ordinary resistors. (I once proved this theory on a Commodore PET). Perhaps this is a good place to mention the "hand in pocket" rule: if you're working on a high-voltage system, and one hand is in your pocket, it can't be touching a good earth (unless you're even odder than I am :-)) so there's a reduced chance of current crossing your body. You used to often see TV engineers with one hand in a pocket and an EHT probe in the other. -- Pete Peter Turnbull Dept. of Computer Science University of York