On Fri, 31 Mar 2006 00:33:12 -0600, Tim Williams wrote:
"Ignoramus6399" wrote in message
...
I have a bunch of 1N4007 diodes (1000v rated). If I put, say, 20 of
them in series, would that be sufficient to rectify 9,000 VAC safely?

Nah- 9kVAC is 12.7kV peak, call it 15kV peak. The rectifier has to stand
off full voltage on the backswing, so you need 30kV diodes, minimum. 40 or
50kV would be even nicer.

Tim, I lost you a little bit here, sorry. Are you saying that I need
single 30kV diodes and that putting 1 kV diodes in series is
unsuitable? Or are you saying that twenty 1,000 V diodes is not
enough?


I have read some articles discussing that since leakage amps are not
identical, that I need to put resistors in parallel with them. If so,
these need to also be 1kV rated resistors, right?

Yeah, but conversely, I recall reading an article which stated that modern
diodes are avalanche rated, meaning that if the voltage across one diode
increases to say, rated PIV, current starts going up (it looks like a really
high voltage zener diode), pulling it back into balance.

Yes, tat would be very nice.

i