Re: Inside power supplies: Where are the shocks?

["Scott Alfter" <salfter@NiObSmP.AnMe!t>]

Slick wrote in message <357DDBA8.7798@hotmail.com>...
>Would you rather be shocked by 10,000 volts at one amp or 10,000 amps at
>one volt? It doesn't matter. There is the same amount of energy in each
>shock.


100 mA is generally regarded as a lethal current.  An ordinary flashlight
battery can deliver much more current than this, yet you can touch your
fingers to the terminals and it won't kill you.  Why?

Think Ohm's Law.  If the resistance between, say, two fingers is around
5-10k (which is probably on the low side unless you're wet), 1.5V across
that yields a current flow of no more than 300 uA, which you won't even
feel.  Stick your fingers in a wall outlet (120V) and you're looking at 24
mA...not fatal if it's only going through the fingers of one hand, but it'd
be painful.  (It's even odds if that current takes a path through your body
that goes through the heart.)  10 kV, to use your example, would result in a
current of 20 A.  Electric chairs, by comparison, usually run at about 2 kV,
so you can imagine what effect 10 kV would have.  "Volts jolt, but mils
kill," or something like that.

A 1 V source isn't gonna be able to force 10 kA through you.

Scott Alfter
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