Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!uunet!zephyr!tektronix!tekcrl!tekgvs!arnief
From: arnief@tekgvs.LABS.TEK.COM (Arnie Frisch)
Newsgroups: sci.electronics
Subject: Re: HV Cap Fun!
Summary: Then there's the effect of temperature.....
Message-ID: <5248@tekgvs.LABS.TEK.COM>
Date: 31 May 89 23:20:12 GMT
References: <4924@m2c.M2C.ORG> <3186@kitty.UUCP> <7487@bsu-cs.bsu.edu> <1418@ns.network.com>
Organization: Tektronix Inc., Beaverton, Or.
Lines: 20

In article <1418@ns.network.com>, logajan@ns.network.com (John Logajan) writes:
> In article <7487@bsu-cs.bsu.edu>, dhesi@bsu-cs.bsu.edu (Rahul Dhesi) writes:
> > You can discharge some electrolytic
> > capatitors, remove the short circuit, and after a few minutes the
> > capacitor regains a smaller charge.
> 
> This is not uncommon especially in high-voltage capacitors, including

Another problem is that some capacitors can assume a charge after they
have been shorted as a result of changing temperature.  This is
especially true of ceramic capacitors.

You discharge it at 20 degrees C and then you just heat it up to - say
50 degrees C - and you find it's charged up to a significant voltage
again, maybe enough to give you a nasty jolt.


(It happened to me.)
Arnold Frisch
Tektronix Laboratories