Re: Diode strings - equalizing resistors

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

Original poster: "Steve Cook" <steve-at-g8cyerichmond.freeserve.co.uk> 

Generally speaking I have found that resistors are more susceptible to
failure than modern diodes. The usual failure mode is of course o/c, this
then puts the full voltage across a single diode, and boy can they go with a
bang! 1N4007s are so cheap even in small quantities that I don't think it is
worth the effort of fitting equalising resistors, given the attendant risks.
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, September 21, 2004 2:59 PM
Subject: Re: Diode strings - equalizing resistors


 > Original poster: biomed-at-miseri.winnipeg.mb.ca
 >
 >
 > Well I did this with a batch of 1N5408 diodes, 1000PIV 3 amp rating about
8
 > years ago.  I used 4 diodes in each leg of a full wave bridge with
 > equalizing resistors to use on 3kv (I should have used more diodes for
 > surges and variations).  The resistors were required because the reverse
 > leakage was different on each diode.  I used the nS (nano siemens) range
to
 > measure the reverse resistance of each diode and grouped the close ones to
 > use on each leg of the FW bridge.  In a full wave bridge each diode sees
 > Vpeak of the transformer.
 >
 > Shaun Epp
 >
 >