From: "Tom Del Rosso"
References: <0001HW.B9D43FDF0325BBB11662EAD0@news.covad.net> <0001HW.B9D4EE870344BA681662EAD0@news.covad.net>
Subject: Re: Difference between AC adapter and charger?
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NNTP-Posting-Date: Fri, 18 Oct 2002 12:48:50 GMT
Organization: AT&T Worldnet
Date: Fri, 18 Oct 2002 12:48:50 GMT
"DaveC" wrote in
> On Thu, 17 Oct 2002 19:54:28 -0700, Bob Wilson wrote
> (in message ):
> > The way cheap chargers are made using wall warts is that a resistor
> > in series to control the charging current. Good ones use a constant
> > source. Really good ones sense the slight voltage depression that
> > when the cell reaches full charge, and this causes them to shut off
> > least throttle back the current.
> Thanks for your post.
> Is it simply a constant current source with no feedback, no sensing of
> battery state?
In the "middle" quality units, yes.
> And the "really good ones", how is the voltage depression sensed? With
> charger connected, and it is well-regulated, I'd presume, wouldn't a
> depressed voltage be nigh inpossible to detect? Is the charger
> regularly, and the battery state sensed?
No, you're forgetting it's *current* regulated. When you say
"well-regulated" you're thinking of voltage regulation, which would make
it impossible, but with current regulation there's no difficulty at all.