From: "JACK L. URETSKY (C)1998; HEP DIVISION, ARGONNE NATIONAL LAB ARGONNE, IL 60439" <JLU@HEP.ANL.GOV>
Date: Sun, 10 Jan 1999 13:03:24 -0600
Hi all-
Paul o Johnson writes:
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I rigged up an old variac with its output connected to two brass screws about
two inches apart and also to an AC voltmeter. I put a 100-kohm current-limiting
resistor in series with one lead to the screws. I ask a volunteer to place two
fingers of the same hand on the screw heads (to avoid sending any current
through the chest) and use the other hand to slowly turn the variac up from
zero while watching the voltmeter. So the individual student is in complete
control of the voltage between the finger contacts.
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I do not think that it is good sense to connect a student to a 115 V
house supply in any way, shape or form. I get excellent shocks by connecting
a Ford coil to a 9 V battery - the sparks are a few thousand volts and definitely
unpleasant. For milder shocks, use smaller coils like those found in doorbells.
I suspect that everyone has experienced the kind of shocks that are generated
by walking across a carpet in dry weather.
Regards,
Jack
"I scored the next great triumph for science myself,
to wit, how the milk gets into the cow. Both of us
had marveled over that mystery a long time. We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
Mark Twain, Extract from Eve's
Autobiography