Re: battery

[Ludwik Kowalski <kowalskil@MAIL.MONTCLAIR.EDU>]

Hi Bernard;
The envelope wit CR-39 came. Unless I hear
from you that the address is not good I well
mail to a $12 check for B. Cleyet (tomorrow)

B.C.
134 Hawthorn St
salinas, CA, 93901-3116

What happened to your $100 order? I did not
want to deprive you of the only pieces you had.

Best regards,
Ludwik

On Wednesday, Mar 24, 2004, at 02:12 America/New_York, Bernard Cleyet
wrote:

> "I[n] 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."
>
>
> Student project:
>
>
> place load resister in a calorimeter (with water)  and the cell in
> another.   monitor continuously (Vernier) the current thru and
> potential across the resister, in addition to the temperatures (more
> Vernier)  [note maximum transfer theorem]
>
> bc
>
> p.s. L!   Get an un-electronically regulated P/S with a single cap.
> filter.  Observe the output w/ an o'scope  while varying the load, the
> value of the capacitance, the value of an inserted resistance between
> the rectifier and the cap.  Also with the other 'scope channel,
> observe the charging current by using the potential across the
> inserted resister. WATCH OUT for common grounds and electrified 'scope
> chassis.  [15 V supply safer than a 300 V one]
>
> Horowitz and Hill devote some time on power supply ripple.   sections
> 1.27 and 6.13  (second ed.)
>
>
> Ludwik Kowalski wrote:
>
> > 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