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From: flaig@cit-vlsi.Caltech.Edu (Charles M. Flaig)
Newsgroups: sci.electronics
Subject: Re: shock box
Message-ID: <5736@cit-vax.Caltech.Edu>
Date: 11 Mar 88 21:19:22 GMT
References: <307@trwind.ind.TRW.COM> <4881@videovax.Tek.COM> <1231@uop.edu> <3616@bloom-beacon.MIT.EDU> <2945@zodiac.UUCP> <1091@PT.CS.CMU.EDU>
Sender: news@cit-vax.Caltech.Edu
Reply-To: flaig@cit-vlsi.UUCP (Charles M. Flaig)
Organization: California Institute of Technology
Lines: 41
Keywords: Some real data...

In article <1091@PT.CS.CMU.EDU> phd@SPEECH1.CS.CMU.EDU (Paul Dietz) writes:
>From "The Current that Kills" in October '87 IEEE Potentials
>
>1 - 3 mA	Mild Sensation
>3 - ~10 mA	Painful Sensation
>~10 - 30 mA	Cannot let go. Current may increase to fatal level.
>30 - ~75 mA	Breathing stops, often fatal.
>~75 - ~250 mA	Heart fibrillation in 1.4 seconds, usually fatal.
>~250 mA - 4 A	Heart stops during shock, may restart if current removed
>		before death occurs.
>4 - 10A		Severe burns, not fatal unless vital organs burned.

Since most shock box circuits only deliver a single short pulse, I would
interpret this table to mean that shock boxes delivering 250mA are safe.
And possibly up to 4 A depending on how reliably a heart restarts after
a current pulse (after all, this is something they use to restart hearts
in an emergency).

I remember a time in my foolish youth when I was playing with carbon arc
lamps using salt-water rheostats to limit the current.  At one point I
was using a transformer to step the line voltage up to several hundred
volts for easier arc ignition.  Naturally a time came when my hands were
damp with salt water, and I was holding onto a conductor on one side of
the arc lamp and touched my other hand to the other side to adjust the
spacing.  I've never been kicked in the chest by a mule before, but I
think I learned what that description refers to!  Luckily having all of
my muscles convulse also threw me and my chair over backward and broke
the connection, but I was shaky for the rest of the evening.

Needless to say, I have been MUCH more careful ever since.  Maybe I
will live to a ripe old age after all.  Be VERY careful when you play
around with high voltages, or when you play with relatively low voltages
which make very good contact (such as with wet skin).  Either one can
produce the current which can kill you.

______________________________________________________________________________
  ___   ,               ,                                           ,;,;;;,
 /   Y /|              /|              Charles Flaig                ;/@-@\;
|      |/     __, ,__  |/              flaig@csvax.caltech.edu       | ^ |
|      /^\   /  | | |  /  /\  /\                                      \=/ 
 \____/|  \_/|_/\_/ \_/ \_\/_/_/_/     "What, you think they PAY me for this?"