I was always taught that high-voltage DC is the more dangerous, because AC
causes muscle spasms and DC causes muscle contraction, therefore you're less
likely to be able to let go of something that's shocking you if it's a DC
source.

I once saw a guy connect 60+ 9-volt alkaline batteries through the palms of
his hands.  He had to jump up and down until they fell out of his hands,
because his hands and arms clamped down so tightly.

Another use of high voltage DC may come around soon:  I've heard of
streetcars which use large banks of low voltage, high capacitance (2000+
Farad) capacitors in series to store energy when slowing down, then use that
energy to help speed back up.

Mike H.

>From: Tal <tal@ZAPTA.COM>
>Reply-To: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
>To: PICLIST@MITVMA.MIT.EDU
>Subject: Re: [OT] Saftey issues: AC vs DC
>Date: Sat, 26 Apr 2003 10:49:57 -0700
>
>The main problem with DC is that it is difficult increase/decrease its
>voltage and therefore, it cannot be transmitted efficiently over long
>lines (the old Edison vs Westinghouse debate
>http://www.raintaxi.com/online/1997fall/bloodvolts.shtml). AC allows you
>to transfer the same amount of electrical power with less loses on the
>wires(high voltage, low current).
>
>There are special cases when high power DC system are used (e.g.
>conventional submarines with huge banks of batteries and voltages in the
>range of hundreds of volts) but I don't think any country uses DC for
>power transmission.
>
>As for danger, I think that if you compare DC and AC of the same voltage
>rating, AC is more dangerous because the actual momentary voltage can go
>higher than the DC. This is because the AC voltage rating is typically
>done by RMS which is kind of a average and is lower than the max peak
>voltage.
>
>Hope this helps,
>
>Tal
>
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of John Pearson
> > Sent: Saturday, April 26, 2003 6:46 AM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: [OT] Saftey issues: AC vs DC
> >
> >
> > Is it true that DC is more dangerous, electrocution wise, than AC.
> >
> > Is it true that some countries use DC?
> >
> > If so, what is the voltage?
> >
> > Thanks
> >
> > John
> >
> > --
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>
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