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Subject: Re: Shamingly obvious question about NiMH vs NiCad chargers
From: George Michaelson (ggm_at_apnic.net)
Date: 2002-11-26


On Mon, 25 Nov 2002 18:45:45 -0600 gerald clark <gerald_clark_at_mindspring.com>
wrote:

> The current rating on a DC power supply is the maximum current that can
> be supplied without exceeding allowable ripple in the output.
> It is not a current limiting specification, but a current supplying
> specification.
> You may use less than the rated current, but you can not use more
> without risking damage to the equipment being powered.
>

So when I tried to run my device on a 9v/300ma rated DC plugpak, I was in
dangerous ground. Ok. I won't try that again!

> George Michaelson wrote:
> > God, how embarrassing not to know these things.
> >
> > If one owns an older tandy (blush) NiCad charger, is this 'safe' to use to
> > re-charge NiMH or are they radically different and require a different
> > charger and current?
> >
> > Also, I spoke to a source of AC/DC plugpacks yesterday and he was pretty
> > adamant that the current limiting requirement to 600ma from the 9v pack or
> > 1.2a from the 12v pack was meaningless, it was the device which determined
> > how much current was drawn. I didn't buy this, but also I don't
> > *understand* this area.
> >
> > I'm not an electrical engineer. I don't even play one in Soap Operas. I
> > don't intend risking my device either, so I'm sticking to my US charger in
> > a 240v->110v stepdown unit until I can get a regulated 9v/600ma DC block.
> > I tried one rated to 300ma, it didn't charge, but it does trigger the
> > poweron behaviour of the volts-in, I guess thats a mechanical switch
> > right?
> >
> > -George
> >
>
>
> --
> Gerald L. Clark
>
> Aero TerraTrike #1
> http://www.wizwheelz.com/images/clarkaerotrike1.jpg
>
> Member: Sky Soaring
>
> Illinois, U.S.A.



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