From: Spehro Pefhany
Subject: Re: how to operate a battery-powered device from DC wall wart?
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Date: Fri, 13 Dec 2002 05:42:05 GMT
NNTP-Posting-Date: Fri, 13 Dec 2002 00:42:05 EST
On Thu, 12 Dec 2002 21:24:33 -0800, the renowned J81
>Hi. I have this little battery-powered motor system which runs on a
>1.5V C-cell battery. I'm curious what the best way to determine the
>device's current and voltage needs would be, and then how I would go
>about creating a simple interface to a wall wart transformer in place
>of the battery.
An inexpensive multimeter or two will tell you this, within 10% or so
easily (which is probably all you need). You probably want to know
the stall current of the motor, the running current and the
voltages in both cases. Of course the battery will change as it
ages. Sorry if this suggestion is beneath you, but connect the
ammeter in series with the battery- if you connect it in parallel,
even for an instant, you'll be looking for a new (5x20mm ?) fuse or
>The reason for this request is that I'm doing a lot of research and
>development with this thing, and I'm just eating through batteries
>left and right. :(
>Any information on C-cell batteries, battery power -> dc power supply
>conversions, or anything that you think is related to my situation,
>would be greatly appreciated.
Battery data sheets, especially for cheap batteries tend to be rather
sketchy, but here's one to get you started (Matsushita alkaline cells)
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