Alt-BEAM Archive
Message #02079
To: Steven Bolt sbolt@xs4all.nl
From: "Paul B. Webster VK2BZC" pwebster@clinipath.com.au
Date: Wed, 07 Apr 1999 19:00:46 +1000
Subject: [alt-beam] Re: Microcore memory for 100Farad caps.
Steven Bolt wrote:
> But I see that you can also miscalculate: 200 ampere-seconds
> divided by 3.6 is actually 56 mAh :)
Darn! That's what happens when you use a mouse for a calculator!
> 100F at some overload, perhaps 4V would contain 220 mWh. I guess
> (and certainly hope) that the natural current limit would prevent a
> too sudden release.
I doubt it would be particularly impressive, at least no more so than
the other capacitor. The explosion of either a battery or capacitor is
a purely mechanical event consisting of buildup of pressure and steam
due to heat, and its release when the can ruptures.
In the case of the battery, there is virtually no further release of
the potential energy of the chemicals at the point of explosion, and
while some discharge of the stored energy of the capacitor might occur
as a consequence of incidental contact from plate-to-plate during the
demolition of the capacitor, I expect this would be very much limited by
the resistance of the smaller pieces of the plates.
Shorting a high voltage capacitor makes an impressive "crack", but a
low voltage capacitor is much less impressive as it has not much less
internal resistance (larger plates) against the much lower voltage,
i.e., the discharge is proportionately slower.
--
Cheers,
Paul B.
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