Re: high voltage resistors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Your basic 2W resistor will easily hold off 1 kV... The limit (other than
Pdiss) is flashover as creepage across the case. Creepage distances should
be on the order of 3x free air distance, or, say, 10 kV for 1/2"-1"....

Wirewound resistors are normally fairly good for HV, but they have a sort of
spectacular failure mode (now how would I know that?!) where an arc burns
back along the wire....

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, January 20, 2003 7:56 PM
Subject: high voltage resistors


 > Original poster: "Mark Broker by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<mbroker-at-thegeekgroup-dot-org>
 >
 > Hello, all!
 >
 > I'm looking for some inexpensive resistors that will stand off 20kV
 > pulses.  I have
 > no objections to using two or three in series.  I need a value of
 > 30-40kohm.  I am
 > currently using 3 1/2W resistors in series, but question the longterm
standoff
 > ability.  I have been considering the Ohmite OY series - 2W ceramic
 > composition
 > that are about .75" long and .3"diameter, available from Digikey.  But at
 > about a
 > buck each, I'd rather not spend $40 to discover they won't work!
 >
 > Thanks,
 >
 > Mark Broker
 > Chief Engineer, The Geek Group
 >
 >