Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hp-pcd!hpfcdc!hpfclm!hpfcdj!myers
From: myers@hpfcdj.HP.COM (Bob Myers)
Newsgroups: sci.electronics
Subject: Re: capacitance of batteries
Message-ID: <16750005@hpfcdj.HP.COM>
Date: 16 Nov 88 19:25:58 GMT
References: <1988Nov13.001657.21990@utzoo.uucp>
Organization: Hewlett Packard -- Fort Collins, CO
Lines: 26


>Why should anyone want to gainsay you, Henry?  One has only to
>look at the output waveform of the rectified output of the
>alternator with and without connection to the battery to be
>convinced that a large capacitor is involved.

>Forrest Gehrke k2bt

And again I say, nay, yon device is not necessarily a capacitor, simply
because thou canst reduce an AC component with it!  Question: what do you
get if you connect a source supplying a combined AC and DC voltage (the
rectified output of an alternator, say), across a *DC voltage source* with a
fairly low series resistance (say, oh, jest fer grins...A BATTERY!)?  (For
further amusement, consider applying said signal across a "pure" DC voltage
source - i.e., no series source resistance.  Of course, this is meaningless
unless you assume that the AC/DC source includes some source resistance of
its own, but I think you're getting the idea by now.)

Question the second: If the battery in question is really acting as a big
capacitor, comment on the expected phase of the AC current through it,
relative to that of the AC voltage applied across it.  Hmmmmm?


Bob Myers  KC0EW   HP Graphics Tech. Div.|  Opinions expressed here are not
                   Ft. Collins, Colorado |  those of my employer or any other
{the known universe}!hplabs!hpfcla!myers |  sentient life-form on this planet.