Path: utzoo!utgpu!water!watmath!watdragon!gvcormack
From: gvcormack@watdragon.waterloo.edu (Gordon V. Cormack)
Newsgroups: sci.electronics
Subject: Re: Automobile shock hazard (was: shock box)
Message-ID: <5773@watdragon.waterloo.edu>
Date: 17 Mar 88 12:15:34 GMT
References: <560001@hpcljws.HP.COM> <334@eos.UUCP>
Organization: U of Waterloo, Ontario
Lines: 30

In article <334@eos.UUCP>, jbm@eos.UUCP (Jeffrey Mulligan) writes:
> From article <560001@hpcljws.HP.COM>, by jws@hpcljws.HP.COM (John Stafford):
> > I wouldn't quite claim it is safe to work at automobile voltage (12V)
> > levels.  The second factor, current, comes into play here; cars may only
> > be 12 volts, but there are (especially when starting) quite a few amps
> > around.

Give me a break!  12 volts is absolutely safe.  Reminds me of when
people kept fiddling with my science fair project (a long time ago), 
so I put up a large sign:

           DANGER  50,000 OHMS!

Believe it or not, this kept them away.

> My question is:  are there any hazards from the type of shocks
> encountered in auto ignition systems.  I have gotten painful
> little zings just from having my arm touch a spark plug wire
> while reaching over for something else.

Actually this is (fairly) safe.  There are lots of volts, (50KV)
and there is plenty of current, but it is radio frequency AC, and
so travels along your skin, not through your organs.  You may be
startled into a heart attack or something, though!  Don't try touching
High Voltage DC, like in the back of TV sets -- that will kill you
instantly.
-- 
Gordon V. Cormack     CS Dept, University of Waterloo, Canada N2L 3G1
                      gvcormack@waterloo  { .CSNET or .CDN or .EDU }
                      gvcormack@water         { UUCP or BITNET }