Re: Alternating Current

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

  REPOSTING WHAT WAS APPARENTLY LOST. PROBABLY ON OUR SERVER.

Without realizing that this was private, (see below) I responded at
once. But I see no trace of the reply in the sent folder of my computer.
So let me respond again, this time "in public". By the way, the word
"PRIVATE" appended to the subject line, was truncated; my columns are
narrow. A better way to emphasize this is to place the word into the
first line of the message itself.

I agreed with the message, after reading Dave's original more carefully.
And I suggested an experiment for a student project. Repeat what David
did but use a variable frequency generator. We have a Pasco generator
in which the current can be as high as 2 A and whose frequency range
is from less than 0.01 Hz to several kHz. The output d.o.p. can be
adjusted, if necessary. I think they still sell similar generators.

At low f flickering will dominate. At about 30 Hz most humans will
not notice flickering. But the light probes apparently can detect
it. "How does the amplitude of the A.C. component, and its relative
value with respect to the D.C. component, change with f, and why?"
As demonstrated in this thread, a student could learn a lot from
such investigation.

Is a tiny A.C. component (at high f) is due to light or to the
antenna effect? A very simple experiment can answer this question.
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> Ludwik,
> the light varies at a frequency of 120 Hz not 60 Hz.
> so your contribution does not seem quite appropriate.
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