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From: johnbl@tekig5.UUCP (John Blankenagel)
Newsgroups: net.analog
Subject: large capacitors -- low resistance??
Message-ID: <17@tekig5.UUCP>
Date: Fri, 30-Nov-84 12:06:47 EST
Article-I.D.: tekig5.17
Posted: Fri Nov 30 12:06:47 1984
Date-Received: Sun, 2-Dec-84 04:49:35 EST
Organization: Tektronix, Beaverton OR
Lines: 20




> So it was with great expectation that we charged this thing up.  Got a piece
> of 16 gauge wire.  Taped it to a stick.  Sloowly approached the terminals
> with it ... and ... nothing happened.  Apparently these things have a fairly
> low internal resistance so they discharge shortly after the current is
> removed.  Sigh.

     Where did you learn your physics?  These capacitors have a large internal
resistance.  That is one of the trade-offs that had to be made in order to make
a capacitor with 3.3 F of capacity.  They certainly would not be too useful
if they discharged shortly after the current was removed.  The main use of these
capacitors is for such things as battery backup.  They will produce a small
current for a long time, but don't try to filter the high frequency ripple
out of a power supply with them.  It won't work.  If you want to melt wires,
get a large computer power supply capacitor.  That is what they were made
for (and you thought it was to filter power supplys).

John Blankenagel