Re: Diode strings - equalizing resistors

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

Original poster: "robert heidlebaugh" <rheidlebaugh-at-desertgate-dot-com> 

Rick: In times pass Diodes were expensive and not well matched. Now the
diodes are so closly matched from any batch it is not required to use
resistors. Just buy two or three extra from one batch and hook them all up.
        Robert   H
-- 


 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > Date: Mon, 20 Sep 2004 17:09:18 -0600
 > To: tesla-at-pupman-dot-com
 > Subject: Diode strings - equalizing resistors
 > Resent-From: tesla-at-pupman-dot-com
 > Resent-Date: Mon, 20 Sep 2004 17:12:29 -0600
 >
 > Original poster: "Richard W." <potluckutk-at-comcast-dot-net>
 >
 > Hi List,
 >
 > I have a question concerning the use of equalizing resistors on diode 
strings.
 > I've heard it said the reason for the resistors is that if one diode turns
 > off before the others then all voltage may be seen across that one diode.
 > That makes sense if the diode turns off anywhere else but close to zero
 > crossing. But the diode/s won't trun off until the voltage is near or at
 > zero crossing. At that point there really shouldn't be enough voltage
 > anywhere in the string to overwhelm the PIV spec of any one diode if the
 > diodes are rated at 700 vrms or 1000PIV.
 >
 > Is my thinking amiss?
 >
 > Rick W.
 > Salt Lalke
 >
 >
 >