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From: cor@wpi.WPI.EDU (Corydon T Shimer)
Newsgroups: sci.electronics,alt.sex
Subject: Re: HELP!
Message-ID: <1991Jan28.150716.31012@wpi.WPI.EDU>
Date: 28 Jan 91 15:07:16 GMT
References: <1991Jan19.052458.7449@wam.umd.edu> <1991Jan26.041208.25354@athena.cs.uga.edu> <2011@fornax.UUCP>
Organization: Worcester Polytechnic Institute
Lines: 66

In article <2011@fornax.UUCP> wli@fornax.UUCP (William Li) writes:
>In article <1991Jan26.041208.25354@athena.cs.uga.edu>, mcovingt@athena.cs.uga.edu (Michael A. Covington) writes:
>> "It's not voltage that's dangerous, it's current"
>> 
>> But voltage is the force that causes current!
>> That's like saying, "It's not falling that's dangerous, 
>> it's hitting the ground."
>
>But it *is* hitting the ground that's dangerous.  To get real
>silly, I could say that falling onto a large airbag from a tall
>building is not at all dangerous, but falling from a lesser
>height onto concrete will likely do some grievous bodily harm.

	This is a poor analogy.

>
>Granted, voltage makes the current go.  In the case of the
>human body, though, it makes more sense to say that
>
>	I = V/R
>
>than to say that
>
>	V = IR
>
>We know that a given amount of current (say, 100 A) through a
>given body part (say, your heart) will do a given amount of
>damage (say, turn your heart into black char).  You can't
>say the same thing for voltage, because resistance conditions
>in the body are so variable.  Thus, putting your dry hand on
>a metal ball at 10,000 V with your feet up on a plastic milk
>carton will make your hair stand on end and nothing else.
>Stand in a puddle of water connected by a conducting path
>to the ground of the same 10,000 V metal ball, and *then*
>see if "there'll be a hot time in the ol' time tonight."

	But why do you think that you have to stand on the 
	plastic milk carton?! This is to make
	the Resistance very great... I = V/R ...
	which makes the current very small...

	Standing in a puddle would indeed make the current
	great... 

	I once saw a girl in my physics class get hurt
	because she stood on a rubber stool and held onto
	a 10k Volt "ball".... for about a minute, and the
	electricity arcced (sp?) through the air to the
	floor with a loud snap! ... probably like charging
	up a capacitor and having it release all it's
	stored energy...

>
>Current kills.

	True, it is the current that kills, but high voltage
	can cause high current, given the right situation.

	I would not suggest plugging in a vibrator into a
	220 Volt outlet (when it's made for 120) because 
	"It's the current that matters"...   :)

>
>(so do a lot of other things, too, come to think of it.
> Like, for example, standing idly in the middle of a
> flame.)