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Re: battery

Tuesday, Mar 23, 2004, at 19:40 America/New_York, Brian Whatcott wrote:

If we are still talking about a "stiff" AC source feeding a rectifier
diode
and smoothing cap., then increasing output currents will reduce the
average DC voltage at the output, while increasing its ripple
amplitude.

Brian W

At 04:09 AM 3/23/2004, you wrote:
Consider an ideal transformer (without
copper and iron losses). Will the DOP
decrease with increasing currents or not?
Ludwik Kowalski

The reductions of "the average DC voltage at
the output, while increasing its ripple amplitude"
are undeniable experimental facts. Bernard
wrote that the reduction is caused by "copper
and iron losses." But I am not convinced that
an attempt to minimize copper losses (using
a thicker wire) or iron losses (using thinner
transformer sheets etc.) would reduce the
difference between the open circuit voltage
and the DOP (difference of potentials) at the
source terminals.

I suggested a different cause (model). What
is wrong (or unscientific) in choosing among
subjective models of objective reality? But
all this is philosophy. I my class today I did
follow the textbook. I said that a battery
behaves as if it had an energy loss
visualized as an internal resistance. I did
not say that a resistance inside a battery
"is responsible for" the dependence of
the DOP on current. Did it make any
difference? Probably not. Most students
are not ready to appreciate nuances.
Ludwik Kowalski