[ARC5] Clarification -T22 Request for Conversion Info

Wed, 6 Mar 2002 10:02:21 -0800 (PST)

Dave,

I believe any capacitor (like mica, disc ceramic,
plastic, poly, etc) that employ a dry dielectric
should last forever. The only problem with dry
dielectrics is they are limited to low value
capacitors. Paste (or wet) dielectrics are needed for
high value caps. I do not see any problem with mica,
it essentially a sliced up rock.

Capacitors (like electroylitic, paper, etc) that
employ a paste dielectric have a limited lifetime
because the dielectric dries out over time and is no
longer effective.

An exception to this rule, appears to be oil filled
capacitors. I still use 60+ year old ones with no
problems at all.

Regards Tino, VE2GCE

--- David Stinson <[email protected]> wrote:
> 
> 
> "J. Forster" wrote:
> 
> > I believe that caps can be reformed if the
> appropriate voltage is applied
> > carefully. Leakage in non-electrolytics may well
> be moisture related and warming
> > or applying voltage might help with that...
> 
> I'd like to see some work on this.
> Does anyone know if the mica leaks moisture?
> I wonder if this is why they replaced the mica with
> ceramic on late and type-12 production.
> 73 Dave S.
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