Is ringing voltage dangerous?

From: John Wilson <wilson_at_dbit.dbit.com>
Date: Mon Feb 28 16:22:10 2000

On Mon, Feb 28, 2000 at 08:55:33AM -0700, Richard Erlacher wrote:
> The ringing voltage is over 250 volts peak-to-peak but at a high enough
> voltage to make you jerk your hand away if you touch it. The voltage range
> that's most dangerous is from 25volts to about 60 volts, as it won't make
> you jerk your hand (or other body part) away, yet it is capable of
> disrupting normal operation of the cardio-vascular system.

I guess it depends on a lot. When I was in 6th grade I tried to build my own
inverter, using a 12V lantern battery and a buzzer in series with the secondary
of a doorbell transformer. Didn't get 110V like I was hoping but it gave
off a nice 50 V according to my voltmeter (the finest that $8.95 would buy
at Shack!). So being the well-adjusted, popular kid I was, I installed the
whole mess in a lunch box and went to school and zapped everyone who didn't
jump out of the way fast enough! No real ill effects (well I think I got
punched a few times for some reason, but that's different), but I suspect the
key was that it was probably a pretty low duty cycle, and more importantly
I used a normal 110V cord and plug for the 50V end, so it was being applied
to only 1/2" of skin, as opposed to going in one arm and out the other etc.

Naturally my friends (the few I had left after that) wanted in, so they
put together high voltage lunch boxes too. One friend's father worked for
an electronics company (General Scanning in Watertown, MA, I never really
understood what they make though) and used to hang around there after school,
and one of the engineers liked the idea and put together a little transistor
inverter circuit for him which got 170 V instead of 50. The engineer wisely
put a big series resistor on so no one got hurt by that either, it bit a lot
harder though, and the kid was able to fool people into getting into range
because at least *his* lunch box wasn't loudly buzzing!

Anyway in retrospect, this was all insanely dangerous, because it *really*
depends on how good a connection you get, how dry the person's skin is,
whether they have any unknown heart problems, etc. I've *heard* that it's
possible to build up a resistance to this kind of thing but that sounds
pretty fishy to me, it's not that kind of thing. I think it's more just
hit and miss, I've zapped myself with all kinds of voltages as I'm sure
most people on this list have, but still you occasionally hear of someone
being killed by some pitiful amount just because it caught them the wrong
way.

Did anyone see the tape a few months ago on 60 Minutes or Dateline or whatever,
showing the two founders of a company that sells "air tasers" demonstrate
their supposed safety by shooting each other with them? I was impressed,
it looked a no-kidding-around shock... And the needles have gotta hurt too,
unless I misunderstood that part. I assume it's high frequency or uses short
pulses or something though. And the nice thing about small shots of really
high voltages is, charred skin doesn't conduct nearly as well! Built-in
fail safe system... well maybe not!

John Wilson
D Bit
Received on Mon Feb 28 2000 - 16:22:10 GMT