Why were so many British cars positive earth?

y_p_w wrote:
>
>
> Back in my days as an electrical engineering student, we referred to
> positive current as the movement of "holes", and negative current as
> the movement of electrons. Of course everything has to do with the
> mass movement of electrons, but the convention of "positive current"
> never changed.
>
> Electrons and holes are also used to describe semiconductor doping.
>

But holes only move in semiconductors, not normal wires.

It is an even more useless argument than how many angels dance on the
head of a pin. In a normal conductor the electrons do not actually
"move" very far at all. Not even the free electrons. They move a
little- the E field from that forces others to move, etc. It is like a
bunch of balls sitting in a trough- one comes in, bangs stream of balls,
one on end moves off, balls move about one diameter. Yeah, Es move a
bit farther than their "diameter" but there is not really a stream of
individual electrons moving down a wire and leaving the end like water
in a pipe.

Ototin wrote:
>>
>>I'd like to know why the hot wire in car wiring is red and the ground
>>wire is black, but at home it's the black wire that's hot.
>
>
> In house wiring the red wire is also "hot".
>

and the white wire can be hot too if it's got black tape on it.

My comment was just that it's "backwards" from cars and regular
electronics - black is ground unless it's house wiring. I only do house
wiring projects about once a year and I always have to remind myself
of that...

"ray" > wrote in message
...
> Ototin wrote:
> >>
> >>I'd like to know why the hot wire in car wiring is red and the ground
> >>wire is black, but at home it's the black wire that's hot.
> >
> >
> > In house wiring the red wire is also "hot".
> >
>
> and the white wire can be hot too if it's got black tape on it.
>
> My comment was just that it's "backwards" from cars and regular
> electronics - black is ground unless it's house wiring. I only do house
> wiring projects about once a year and I always have to remind myself
> of that...

You haven't worked on German or Swedish cars. Brown is ground and black is
hot.

"Don Stauffer" > wrote in message
...
> y_p_w wrote:
> >
> >
> > Back in my days as an electrical engineering student, we referred to
> > positive current as the movement of "holes", and negative current as
> > the movement of electrons. Of course everything has to do with the
> > mass movement of electrons, but the convention of "positive current"
> > never changed.
> >
> > Electrons and holes are also used to describe semiconductor doping.
> >
>
> But holes only move in semiconductors, not normal wires.
>
> It is an even more useless argument than how many angels dance on the
> head of a pin. In a normal conductor the electrons do not actually
> "move" very far at all. Not even the free electrons. They move a
> little- the E field from that forces others to move, etc. It is like a
> bunch of balls sitting in a trough- one comes in, bangs stream of balls,
> one on end moves off, balls move about one diameter. Yeah, Es move a
> bit farther than their "diameter" but there is not really a stream of
> individual electrons moving down a wire and leaving the end like water
> in a pipe.

It is true that the effect of electron movement is important rather than the
distance an individual
electron travels. The convention of current being defined as flow of
positive charge, or its effect,
has been there for a long time, long before hole movement was shown to be a
reality. This is standard university physics (and chemistry).

There are few cases where the actual direction makes much difference in
practice. As another
poster mentioned, corrosion can be induced by current, where there is an
external electrolyte path.
There are some snakeoil 'cathodic protection' devices sold by schlockmeister
companies and they
have been cited on this group. They are all but worthless for general
automobile corrosion.

In high school, my physics teacher dodged the positive ground question by
saying that it was believed there were certain advantages. (He never said
what they were supposed to be.)

Maybe just the British tradition. Their practice of driving on the left at
least had a reason.

"AZ Nomad" > wrote in message
...

> DC flows in a circle. It makes absolutely no difference which side you
use
> as your reference.

Believe it or not, I bought a used Fiat 131 Mirafiore for my x-wife and upon
one occasion
the battery ran down for some unrelated reason. I took it out of the car to
charge it, and
something was very very wrong. The negative post on the battery was
connected to the
positive battery cable. No doubt about it. There was still enough voltage
on the battery
to measure and sure enough, the negative terminal was positive.

Someone had charged it in reverse, and it had worked that way for a long
time.

I discharged the battery and recharged as God and Exide had intended, dealt
with the
unrelated problem, and started it up. Never had another problem. I would
not have believed
this was possible, but it did happen.

Don Stauffer wrote:

> y_p_w wrote:
>
>>
>>
>> Back in my days as an electrical engineering student, we referred to
>> positive current as the movement of "holes", and negative current as
>> the movement of electrons. Of course everything has to do with the
>> mass movement of electrons, but the convention of "positive current"
>> never changed.
>>
>> Electrons and holes are also used to describe semiconductor doping.
>>
>
> But holes only move in semiconductors, not normal wires.

In a pure sense, yes. But "holes" have been used as an abstraction to
describe positive current in a conductor. I never said it was accurate.

> It is an even more useless argument than how many angels dance on the
> head of a pin. In a normal conductor the electrons do not actually
> "move" very far at all. Not even the free electrons. They move a
> little- the E field from that forces others to move, etc. It is like a
> bunch of balls sitting in a trough- one comes in, bangs stream of balls,
> one on end moves off, balls move about one diameter. Yeah, Es move a
> bit farther than their "diameter" but there is not really a stream of
> individual electrons moving down a wire and leaving the end like water
> in a pipe.

Well - in a typical metal conductor there's really just a sea of free
electrons. Push one in at one end and another pushes out at the other
end.

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On Thu, 23 Jun 2005 06:02:51 -0400, Nate Nagel >
wrote:

>> DC flows in a circle. It makes absolutely no difference which
>> side you use as your reference.
>
>Actually it does when you finally get to the coil. Other than that
>you're right there's not much difference.

Not bad for a canned answer, but that's beside the points.


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--
-john
wide-open at throttle dot info

On Thu, 23 Jun 2005 03:46:15 GMT, Jon C > wrote:


>AZ Nomad wrote:
>> On Wed, 22 Jun 2005 19:25:01 -0400, Ototin > wrote:
>>
>>
>>
>>>On Wed, 22 Jun 2005 10:56:23 -0500, ray > wrote:
>>
>>
>>>>Hugo Schmeisser wrote:
>>>>
>>>>>I did some Googling and came up with nothing. Hard to believe no one
>>>>>else has apparently ever asked this question. Or maybe I'm looking in
>>>>>the wrong place.
>>>>>
>>>>>Anybody know? (Besides "because they were British", that is...)
>>>>
>>>>probably the same reason that Honda engines spin backwards.
>>>>Because that's the way they did it?
>>>>
>>>>I'd like to know why the hot wire in car wiring is red and the ground
>>>>wire is black, but at home it's the black wire that's hot.
>>
>>
>>>In house wiring the red wire is also "hot".
>>
>>
>> Black is hot, IIRC.
>> White is neutral.
>>
>> Red is only used for three plus ground as in wiring for a 3-way (three terminal
>> actually) switch.

>How do you figure one wire is hot while the other is neutral in AC wiring?

One is tied to a common point and at nearly zero voltage to ground (neutral).

Also, the hot is the one that is switched.

John Kunkel wrote:
>
> "Hugo Schmeisser" > wrote in message
> ...
> >I did some Googling and came up with nothing. Hard to believe no one
> > else has apparently ever asked this question. Or maybe I'm looking in
> > the wrong place.
> >
> > Anybody know? (Besides "because they were British", that is...)
>
> It actually makes more sense (to me) to have a positive ground since DC
> current flows from negative to positive.

Its a British car. Which way does the smoke travel?

;-)

--
Paul Hovnanian
------------------------------------------------------------------
I used to get high on life but lately I've built up a resistance.

AZ Nomad wrote:
>
> On Wed, 22 Jun 2005 19:25:01 -0400, Ototin > wrote:
>
> >On Wed, 22 Jun 2005 10:56:23 -0500, ray > wrote:
>
> >>Hugo Schmeisser wrote:
> >>> I did some Googling and came up with nothing. Hard to believe no one
> >>> else has apparently ever asked this question. Or maybe I'm looking in
> >>> the wrong place.
> >>>
> >>> Anybody know? (Besides "because they were British", that is...)
> >>
> >>probably the same reason that Honda engines spin backwards.
> >>Because that's the way they did it?
> >>
> >>I'd like to know why the hot wire in car wiring is red and the ground
> >>wire is black, but at home it's the black wire that's hot.
>
> >In house wiring the red wire is also "hot".
>
> Black is hot, IIRC.
> White is neutral.
>
> Red is only used for three plus ground as in wiring for a 3-way (three terminal
> actually) switch.

Incorrect. Red is most certainly a "hot" lead in house wiring. For 240v
circuits such as stoves, dryers, large A/C, etc. you have both black and
red hot leads along with your ground and if needed a neutral.

Also as someone else has noted, white wires can also be hot leads if the
ends are marked with black or red tape.

Pete C.