From: Spehro Pefhany
Subject: Re: maximum reverse voltage allowed on electrolytic caps?
References: <firstname.lastname@example.org> <email@example.com> <firstname.lastname@example.org>
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Date: Thu, 14 Nov 2002 15:34:27 GMT
NNTP-Posting-Date: Thu, 14 Nov 2002 10:34:27 EST
On Thu, 14 Nov 2002 13:40:05 -0000, the renowned "Ian Buckner"
>"Continuous application of reverse voltage without normal
>polarization will result in a degradation of leakage current.
>In conditions under which continuous application of a reverse
>voltage could occur two similar capacitors should be used in
>a back-to-back configuration with the negative terminations
Right, the application of a VERY small reverse voltage
continuously is not covered in these specs. Based on this,
I think 50mV continuous would probably be okay, and the <10mV
(basically Vos of the opamp) the OP had in mind would
definitely be okay.
After all, when you connect two caps in back-to-back, one
will get reverse biased a bit, up until the point where
the leakage increases, probably a volt or more.
>Once upon a time Philips used to do some aluminium parts
>that were actually specified for (low) reverse voltage operating.
>"Solid aluminium electrolytic" as I recall, since discontinued.
>They were intended to compete with the bead tantalums, but
>were more expensive.
This is the first time I've actually seen a cap spec'd for
reverse voltage operation. Doesn't mean they won't work,
just that the manufacturer doesn't characterize them for
that mode of operation. Like BJTs in reverse.
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