Jerry McDonald wrote:
> I'm taking a class on electrical troubleshooting for work. The instructor
> asks which direction does electricity flow pos to neg or neg to pos? In my
> ignorance I pipe up with "both".
In actuality you were somewhat right.
Electrons flow one way (from negative to positive). The "holes", or
abscense of electrons, flow the other way.
This is meaningful in semiconductor theory actually. You might
be surprised, but the concept of a "hole" is just as valid for
many concepts as an electron. The whole basis of semiconductors
is actually the geometric combination of two types of silicon,
those that have extra electrons and those that have extra
holes.
> correctly he surmised that in fact the current flowed backwards and
> essentially the whole car was "live". I'm not buying it.
Well, he's wrong of course.
The car is "live" if you are stuck in the notion that
to be more positive is to be more live. However, it is
of course meaningless, either way of looking at the world
works.
His statement is misleading because it implies that
the whole car is "live" and requires special attention
to prevent giant sparks. I think he is confused beleiving
that the chassis is positive but somehow lights and
accessories are grounded negative. This would imply that
the whole car was live and the possibility for shorts
would be enormous.
In reality, it's just the same thing backwards. No
difference in relative "live" ness. On a normal car you
have to be careful when working with wires that are
positive since they can short. In your car, be careful
with the negative wires.
--
Trevor Boicey
Ottawa, Canada
tboicey@brit.ca
http://www.brit.ca/~tboicey/
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