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From article <22066@tis.llnl.gov>, by tjt@ati.tis.llnl.gov (Tim Tessin):
> 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. 

I get 1039 volts and 20 amps (roughly).
Note that these numbers assume a transthoracic impedance of 50 ohms; the
American Heart Association assumes 100 ohms (from the Advanced Cardiac
Life Support textbook). At that impedance, you get 1470 volts and 15
amps. A hell of a shock, any way you cut it. Note that these are maximum
figures, and based on the maximum output of modern defibrillators, 360
joules. This is enough energy to thoroughly fry the body if not used
properly, and can have serious side effects (though not as serious as
death if used correctly). Now you know why the body jerks when
defibrillated, and why we're (supposed to be) extremely careful that
nobody is touching the patient or anything metal the patient may be
laying on while he gets shocked...

I'm not sure about the suqre wave output, though; I'll have to get the
manual for our Lifepak 5 out and look at it some. According to the
manual, the open-circuit voltage across the paddles is 4200 volts.

-- 
Jay Maynard, EMT-P, K5ZC...>splut!< | GEnie: JAYMAYNARD  CI$: 71036,1603
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