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Re: IBM Wearable PC!

From: smithz@kriek.cae.wisc.edu (Zak Smith)
Date: Thu Oct 1 12:42:35 1998
Newsgroups: comp.sys.wearables

On 28 Sep 1998 11:40:23 -0400, R. Adam Moore <gt4551d@prism.gatech.edu> wrote:
>Batteries of x volts in parallel _will_ indeed produce x volts.  However,
>I believe that the current will increase w/ the number of batteries in
>parallel.  ie, an x volt battery might push y amps.  5 x volt batteries in

Sorry..  current isn't "pushed".

If the load (ie, the resistance of the device being powered) is constant, then
the only way for more current to flow through the load is to increase the
supply voltage.  That is:  V = I * R.   So for a constant load with constant
supply voltage, the number of batteries in parallel does not affect the
current.

However, if the load is so small that the current pulled (V/R) is larger
than the amount a single battery can supply  (that is, the load resistance
is close to the built-in resistance of the battery), the load will not
see the full battery potential (it will be divided between the built-in
R, and the load R).  In this case, adding additional batteries in parallel
will increase the voltage across the load, but it will never exceed
the supply voltage (and thus, the current will never exceed V/R).

-z

-- 
# Zak Smith        smithz@cae.wisc.edu (pgp)    http://www.cae.wisc.edu/~smithz
# Univ. of Wisconsin - Madison MSEE Student.   Geek.   "UNIX - it sucks less."

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