A Tough Question - Electrical

[Young Ed]

Aint never heard of jumping with no cables.

Greg I heard a guy who just took his good battery out of his car flipped it over and stuck it post to post under the hood against the dead battery. Crazy! My barber had a model t magneto mounted in his car so that he could just barely touch the bumper of another car and then they couldn't get out without getting zapped

[Don Coatney]

Gentlemen, GENTLEMEN . . . . . .

Sure am glad I provided such gut-busting humor for y'all, but the sad fact remains that my initial question was indeed a serious one. I am doing some technical writing for an antique tractor publication and the issue came up. I actually hoped for some intelligent enlightenment from you . . . . . . and still am hoping for the same.

Dave, DAVE;

It was while searching for an intelligent answer to your question that I stumbled on a most unintelligent and humorous answer to the same question. I felt this foolish answer would enlighten the readers of this forum to the sad fact that not much is known about the question you asked. Even you must admit that there was some good humor surrounding my posting.

Several replies (my initial reply included) indicated that corrosion resistance might have been the prime reason cars of this era used a positive grounding electrical system. I went to and read the information on the links you posted. It appears that several companies have jumped on the bandwagon and have on the market devices to retard rust and corrosion electrically.

The question you posted brings up another question. Why is it most all vehicles produced today are set up for negative grounding systems? This trend began with the switch to 12-volt systems but before generators had been replaced by alternators. Please share any thoughts you have on that subject humorous or otherwise?

[TodFitch]

The question you posted brings up another question. Why is it most all vehicles produced today are set up for negative grounding systems? This trend began with the switch to 12-volt systems but before generators had been replaced by alternators. Please share any thoughts you have on that subject humorous or otherwise?

I heard that the early transistors they were starting to use in the radios required negative grounding. However I am not familiar with any car radio that used any transistors until years later, so that story is probably false.

[Chester Brzostowski]

Gentlemen, GENTLEMEN . . . . . .

Sure am glad I provided such gut-busting humor for y'all, but the sad fact remains that my initial question was indeed a serious one. I am doing some technical writing for an antique tractor publication and the issue came up. I actually hoped for some intelligent enlightenment from you . . . . . . and still am hoping for the same.

Here is what I remember from my college days back in the seventies. First of all positive ground vs. negative ground is nothing more than a wiring convention. The purpose is to use the metal frame of a machine to be one side of an electrical circuit. Up until 1936 with the solid state experiments at Bell Laborites there were two basic theories of electricity, Ion flow and electron flow. With Shockley’s experiments and the resultant explanation called hole theory the way electronic circuits were viewed changed to meet the times and having energy move from a positively charged point to a negative point helped to explain the emerging transistor devices we use today. Because of this the wiring convention was changed for DC circuits to reflect this new technological advance.

My 2 cents from what I remember from college. A further explanation would just get us into the realm of applied physics and I have no desire to go there.

Chet…

[greg g]

I believe that several Euopean and British cars retained postive earthing long after the US manufacturers went the other way. My 60 Austin Healey while 12 V is still positive ground (I believe they changed in 63/4) and I had a 66 or 67 BMW that still was 6 V positive ground.

[Jim Saraceno]

Well Greybeard, Thank you for enlightening us. I'm an electrician and I know AC and DC theory, but I never knew there was any advantage what so ever of one side grounded or the other.

So, I'm with Don. If positive ground was used because it had an advantage (rather than just 50/50 chance), why would they have changed over to negative ground?

Sometimes things become standard even though they don't have an advantage (remember the VHS vs. Beta-max scenario?). Robinson came up with his square bit screw head before Phillips came up with his screw head. It was a better screw head for screwgun type operations and is only recently becoming somewhat prevalent. The problem is Robinson wanted more money than Phillips so Henry Ford made the deal with Phillips and Phillips screws became the standard for almost 100 years.

I just assumed the positive-negative ground standard was standardized just as haphazardly.

[Normspeed]

Here is what I remember from my college days back in the seventies. First of all positive ground vs. negative ground is nothing more than a wiring convention. The purpose is to use the metal frame of a machine to be one side of an electrical circuit. Up until 1936 with the solid state experiments at Bell Laborites there were two basic theories of electricity, Ion flow and electron flow. With Shockley’s experiments and the resultant explanation called hole theory the way electronic circuits were viewed changed to meet the times and having energy move from a positively charged point to a negative point helped to explain the emerging transistor devices we use today. Because of this the wiring convention was changed for DC circuits to reflect this new technological advance.

My 2 cents from what I remember from college. A further explanation would just get us into the realm of applied physics and I have no desire to go there.

Chet…

Chet, it don't get any better'n that.

Now, about that equator thing...

[Chester Brzostowski]

Chet, it don't get any better'n that.

Now, about that equator thing...

Norm,

Electronics was my choosen profession now I work in corporate management but the answer I provide is the answer believe it or not.

Queensbourgh Community College

NY Institiude of Technology

New York City College of Engineering

Course of study, Electrical Engineering

Chet..

[Andydodge]

Pat S had the right idea tho.........when we go to the craper here in Oz we have to wipe right to left...........lol.......otherwise it generates too much static electricity.........and with the available methane..............not a pretty sight..........lol.......kaboom!!

[Chester Brzostowski]

Chet, it don't get any better'n that.

Now, about that equator thing...

Norm,

In further support of my statements I had a long conversation with one of our practicing EEs and he also fully agrees with my explanation.

Early tub theory used electron flow from a cathode (negative) to a plate (positive) to explain the phenomenon of the vacuum tube. Thus from a practical standpoint electricity was perceived as flowing from negative to positive. Those who made the transition from vacuum tubes to transistor theory had a tough time in that electron flow does not explain the practical function of a PNP junction. Movement of charge from positive to negative was more suitable and practical to postulate. The wiring convention change was the slowest in the auto industry but was completely switched over by the end of the 1950’s

As far as one being better for rust prevention my gut feel would be that the early positive ground cars were also made with pure virgin steel and the latter cars with negative ground systems were products of recycled iron.

That’s my 2 cents, no joke, Chet…

[Don Coatney]

I heard that the early transistors they were starting to use in the radios required negative grounding. However I am not familiar with any car radio that used any transistors until years later, so that story is probably false.

Norm,

Electronics was my choosen profession now I work in corporate management but the answer I provide is the answer believe it or not.

Queensbourgh Community College

NY Institiude of Technology

New York City College of Engineering

Course of study, Electrical Engineering

Chet..

Tod and Chet;

Thanks for bring up the transistor issue. I do not recall when transistor radios were first used in automobiles. But I do know when transistor radios were first mass produced.

My dad (born in 1902) was an electrical engineer who was involved mainly with vacuum tube radio design. In the early 1950's he went to work for a company called I.D.E.A. in Indianapolis as a design engineer. This company designed and produced the very first transistor radio dubbed Regency TR-1. This radio hit the market in 1954. Follow this link for the story including an interesting film clip.

http://myweb.msoe.edu/reyer/regency/

I wish my dad were around today as I am sure he would have some insight on the positive-negative ground issues.

[Normspeed]

I believe you Chet. Your explanation really hit the nail on the head.

Norm,

In further support of my statements I had a long conversation with one of our practicing EEs and he also fully agrees with my explanation.

Early tub theory used electron flow from a cathode (negative) to a plate (positive) to explain the phenomenon of the vacuum tube. Thus from a practical standpoint electricity was perceived as flowing from negative to positive. Those who made the transition from vacuum tubes to transistor theory had a tough time in that electron flow does not explain the practical function of a PNP junction. Movement of charge from positive to negative was more suitable and practical to postulate. The wiring convention change was the slowest in the auto industry but was completely switched over by the end of the 1950’s

As far as one being better for rust prevention my gut feel would be that the early positive ground cars were also made with pure virgin steel and the latter cars with negative ground systems were products of recycled iron.

That’s my 2 cents, no joke, Chet…