What stops the fire?

[Tom Wesenberg]

Many people can benefit by thinking of electrical flow as water flow. The hose is the wire and water is the electricity. A switch or faucet can stop the flow, and you need a return wire or hose to complete the circuit. A water pump is like a battery supplying the source for flow and a hose retuns the water back to the pump. The water can do work such as turning a turbine, then return back to the pump, the same way a wire (or car frame) completes the circuit for return of electrons.

More water pressure is like more electrical pressure (volts), and more water flow is like more current (amps). Compare the water flow of a garden hose to a river. The water hose can have high pressure but not a lot of flow. The river can have low pressure but a lot of flow and can do much work. Think of the heavy current to run the starter, but it's low voltage (electrical pressure) is to weak to jump an air gap. The heavy current can do a lot of work like cranking the engine. The coil is low current but high pressure. It's pressure is high enough to jump a large air gap, but the current is too low to do much work. It takes a good flow of water to run a grist mill or electric generator and it takes a lot of current to run the starter.

You can also put a one way valve in the water hose so the water can flow in only one direction. A diode is a one way valve for electricity and allows the current to only flow in one direction. A water valve or electrical switch can stop the flow in both directions.

[Jeff in BC]

What direction does current flow?

Guess what, Bill, the Dog and The Chief have it right - Positive to Negative - and Bill's little men are called Gemlins (at least here in Canada).

The direction of current flow was defined by Andre-Marie Ampere in 1820 and is based on magnetics. Electrons were not discovered until 1897, 77 years later.

All electrical, electronic and magnetic equations are based on current flow from positive to negative.

If you have 5 minutes take a look at the following youtube video and pay attention to the 4 minute mark onwards https://www.youtube.com/watch?v=8gvJzrjwjds .

Jeff

[SkipShift]

For peace of mind get some of this.

[Carter]

Originally Posted by Jeff in BC

What direction does current flow?

Guess what, Bill, the Dog and The Chief have it right - Positive to Negative - and Bill's little men are called Gemlins (at least here in Canada).

The direction of current flow was defined by Andre-Marie Ampere in 1820 and is based on magnetics. Electrons were not discovered until 1897, 77 years later.

All electrical, electronic and magnetic equations are based on current flow from positive to negative.

If you have 5 minutes take a look at the following youtube video and pay attention to the 4 minute mark onwards https://www.youtube.com/watch?v=8gvJzrjwjds .

Jeff

Did you watch that video? It clearly states that, while electrical engineers use what is called conventional current, which is positive to negative flow, that is incorrect. The correct flow from negative to positive is called actual flow, according to the video.

[PC/SR]

Roadster 62: Electro-magnetism is one of the four so far identified fundamental forces of the universe that Einstein spent the last years of his life trying unsuccessfully to figure out so you are in good company if you do not understand it either.
However, the confusing terminology of the direction of electron flow started with Benjamin Franklin and his kite. In the early 20th century the books on electricity used different terminology until the modern terminology (positive to negative) became the standard. Electron flow was always the same; folks just used different terminology to describe it. (See Carter above.)
On a practical Model A level, what keeps your yellow wire from burning up is the resistance of the coil, horn, light bulb filaments and other circuit items and the wire itself. Short the yellow wire directly to ground (virtually no resistance) and it will burn in an instant. The large wire through the battery/starter,which has virtually no resistance, is designed bigger and can carry the load for a short time before it burns out. Check out Ohms law and amperage on the internet, it will get you into the theory.
It may make a difference whether the coil and plugs are positive or negative electron flow, having to do with heat and resistance, but again on a practical Model A level, just make sure everything is the same polarity.
Oh, and if you get it figured out, you get a Nobel prize!!

[Tinker]

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Its more about connecting the two. The postive will not work without the negitive. Its a circuit and draws both ways. Either way the battery that stores the energy is ready with power. Its only when something, including a short, draws a charge does it flow and it only draws what is needed to power what is needed to run what is drawn. Complete a circuit of a bulb on a 12 guage wire all is okay. But try that with a starter, no good. But why doesnt the bulb draw as much poower as the starter? Its directly wired to the battery too? Becuase it does not demand that much power(amperage) to work.

[Jeff in BC]

Originally Posted by Jeff in BC View Post
What direction does current flow?

Guess what, Bill, the Dog and The Chief have it right - Positive to Negative - and Bill's little men are called Gemlins (at least here in Canada).

The direction of current flow was defined by Andre-Marie Ampere in 1820 and is based on magnetics. Electrons were not discovered until 1897, 77 years later.

All electrical, electronic and magnetic equations are based on current flow from positive to negative.

If you have 5 minutes take a look at the following youtube video and pay attention to the 4 minute mark onwards https://www.youtube.com/watch?v=8gvJzrjwjds .

Jeff
Did you watch that video? It clearly states that, while electrical engineers use what is called conventional current, which is positive to negative flow, that is incorrect. The correct flow from negative to positive is called actual flow, according to the video.

Hi Carter

In engineering, electronics or physics if we are talking about electron flow or electron current it must explicitly be stated. If we are talking about current then Ampere's definition is implied and current flows from positive to negative.

Jeff

[PC/SR]

Jeff's last comment illustrates the confusion. The fact is, electrons flow from negative to positive. The terminology changes depending on usage and the user. (Then you can get into wave theory, holes, etc. and all bets are off.)
In a MOdel A, just keep polarity consistent.

[Tinker]

Correct me if i am wrong but outside the charging system (a stand alone power source/generator) a car will run weither connected pos or neg grounded. Resistors & diodes included. Schematic standards i would guess is for continuity.

[Randy in ca]

A lot of the confusion in this thread relates to the existence of two different annotations of current flow - Conventional Current Flow and actual Electron Flow.

The movement of electrons (and therefore the direction of current flow) is from the negative terminal of the battery to the positive terminal. However, before the true nature of electricity was known, scientists assumed that current was the result of the movement of positively charged particles and therefore that current flowed from the positive to the negative terminal. This (incorrect) convention is still used today and is called Conventional Current Flow. When discussing the true nature of current we call it actual Electron Flow. In general, Conventional Current Flow is indicated on circuit diagrams and true Electron Flow is used when we describe how an individual component works.

[PC/SR]

True, a car as basic as the model a will run whether positive or negative grounded. Modern cars will too so long as the computers and everything else are polarized the same.
Basic schematics such as for the Model A show the path of the current, continuity, whether positive or negative ground. No need to change wiring when you change polarity.
A true resistor is not affected by polarity.
A true diode however is polarity sensitive. It will stop flow in one direction, and allow flow in the other direction. A common Model A example is an alternator, which contains a diode which allows current of a certain polarity to flow out, and block current flow in. Hook it up with the wrong polarity and it will burn out. That is why they say, for example, 12 volts, negative ground.

[Roadster62]

I still don't understand any of the above statements, and I'm not sure who is right or wrong. I do know that I have no understanding of the amount of electricity (if that is the correct term)that flows through the wires, but guess is is less than what flows out of a MIG welder. "Bad Ground" is constantly mentioned, and that paint has to be ground off things for the electricty to flow. If that is true for the headlights to work the ball socket that holds the bucket to the bar and all the bolts have to be bare steel were they make contact all the way to the frame for this "loop" to work. Should special grease be used to keep these areas protected from rusting? Bob

[Tinker]

You can use dielectric grease or battery terminal spray (spray might make a big mess) .... or some vaseline if it's not in a high temp area, it will melt.

Okay, thanks PC/SR.
"A true diode however is polarity sensitive. It will stop flow in one direction, and allow flow in the other direction. A common Model A example is an alternator, which contains a diode which allows current of a certain polarity to flow out, and block current flow in. Hook it up with the wrong polarity and it will burn out. That is why they say, for example, 12 volts, negative ground. "

[Roadster62]

Ok, another question about things that can not be seen. Say you wirewheel half of the underside of a bolt to bare steel the other has paint or rust on it. Does the electricty arc between the clean surfaces since the paint/rust will not allow a 100% contact? Bob

Originally Posted by Tinker

You can use dielectric grease or battery terminal spray (spray might make a big mess) .... or some vaseline if it's not in a high temp area, it will melt.

[Tinker]

I guess if the connection was loose you could have arcing. I guess it would also depend on the size of the bolt/connection and the amount of amperage you run through it. But if you have a tight connection then at worst you would have more resistance or lack of flow at that connection over a fully clean surface. My guess anyway.

[Tom Wesenberg]

I never leave bare metal. My lock washers and nuts conduct the electricity just fine. I also put grease on the threads and lock washers to keep the rust away.

[JackA]

Roadster, if you are so interested, you should take a basic electronics class. They are usually provided by your local HAM radio club. Take a look at the ARRL web site.

[Roadster62]

Thanks, but I don't need to get a third electrical school of thought going, house, auto, and now radio, way to overwhelming. Bob

Originally Posted by JackA

Roadster, if you are so interested, you should take a basic electronics class. They are usually provided by your local HAM radio club. Take a look at the ARRL web site.

[Mike V. Florida]

Originally Posted by Jeff in BC

Hi Carter

In engineering, electronics or physics if we are talking about electron flow or electron current it must explicitly be stated. If we are talking about current then Ampere's definition is implied and current flows from positive to negative.

Jeff

I wrote this 8 months ago might help (might not).

I understand the confusion I really do. Schematics drawings and symbols are drawn pos to neg but the actual electrons move neg to pos.

Ever gone to the carnival? Have you seen the chasing lights on the rides? If you look at the lit bulbs the light appears to go one way but if you look at the bulbs that are out they appear to move the other way.

Electricity is the same way. Are you following the electrons or the holes they leave behind.

I have always read drawings and figures out paths pos to neg. While technically wrong the bottom line is that it works either way.

Lets say you follow a wire from the neg side and "bump" into a bulb. The side you "bumped" into is the neg side the other side of the bulb is the positive side. Following the wire to another bulb that side is neg and the other side is pos and so on, neg, pos, neg, pos.