Path: utzoo!mnetor!uunet!seismo!lll-tis!ati.tis.llnl.gov!tjt
From: tjt@ati.tis.llnl.gov (Tim Tessin)
Newsgroups: sci.electronics
Subject: The shock of your life (was Re: shock box)
Message-ID: <22066@tis.llnl.gov>
Date: 13 Mar 88 08:01:41 GMT
Sender: news@tis.llnl.gov
Reply-To: tjt@ati.tis.llnl.gov (Tim Tessin)
Lines: 32

In article <5736@cit-vax.Caltech.Edu> flaig@cit-vlsi.UUCP (Charles M. Flaig) 
writes:
> 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).

Just for fun, calculate the following data to see just what Johnny Gage
and Roy DeSoto are playing around with.  A typical DC Defibrillator used
by your average Paramedic generates a maximum of 400 joules (watt-seconds) 
(actual delivered energy) for a duration of 16.66 msec (assume square wave). 
The trans-thoracic resistance (the resistance across your chest when 
the paddles and conductive gel are used) is anywhere
from 30-100 Ohms (use 50 in your calculations).  Note that these babys 
deliver ENERGY, so they are going to generate as much current and voltage
as necessary to push the total energy through the resistance (the human).
Calculate the instantaneous current and voltage. 

Tim Tessin