Think of voltage as a force. The absolute value of the voltage reading shows the magnitude of the force. The sign, + or -, shows direction.

Voltage is NOT a measure of the force -- the electric field is the measure of the force and it is related to the gradient of the voltage.

Furthermore, this only works if you are thinking in terms of the voltage difference between Point A and Point B. But if, as the TS is doing, you are focusing on the voltage at a given point and trying to understand what it means for the voltage at that point to be negative, this isn't a good analogy at all. If you tell me that the voltage at Point A is +10 V that tells me nothing about either the magnitude or direction of the force at that point. Just consider that you could just as easily chosen a different reference and told me that the voltage at Point A is -1000 V and absolutely nothing has changed physically and whatever that magnitude and direction of the force on a charge at that point was it has not changed one bit.

 

Voltage is NOT a measure of the force -- the electric field is the measure of the force and it is related to the gradient of the voltage.

Furthermore, this only works if you are thinking in terms of the voltage difference between Point A and Point B. But if, as the TS is doing, you are focusing on the voltage at a given point and trying to understand what it means for the voltage at that point to be negative, this isn't a good analogy at all. If you tell me that the voltage at Point A is +10 V that tells me nothing about either the magnitude or direction of the force at that point. Just consider that you could just as easily chosen a different reference and told me that the voltage at Point A is -1000 V and absolutely nothing has changed physically and whatever that magnitude and direction of the force on a charge at that point was it has not changed one bit.

W, I think you are being unduly pedantic.
I don't see anything seriously wrong with thinking of the voltage between two points as a force pushing the electrons through a conductor.

For example, there is no significant electric field gradient from the power station generator to my house, it's across the power lines and across any loads in my house.
The generator is providing a force (voltage) to the electrons at the power station that generates the electric field across the local load.

And of course you can't refer to the voltage at a given point. Voltage is always with reference to some other point.

 

W, I think you are being unduly pedantic.
I don't see anything seriously wrong with thinking of the voltage between two points as a force pushing the electrons through a conductor.

I don't have a serious problem if someone wants to think in loose terms that way -- which is why there is a "furthermore" in my response to begin with.

For example, there is no significant electric field gradient from the power station generator to my house, it's across the power lines and across any loads in my house.
The generator is providing a force (voltage) to the electrons at the power station that generates the electric field across the local load.

It's the voltage gradient, not the field gradient, that produces the force. If there is a voltage drop across the power lines, then there is an voltage gradient across the power lines and, thus, there is an electric field present that exerts a force on the electrons.

And of course you can't refer to the voltage at a given point. Voltage is always with reference to some other point.

That's the whole point that the TS is struggling with -- trying to wrap their head around what it means when they see that the voltage at some point is some value that happens to be negative. They are having difficulty coming to terms with the fact that any such description carries along with it an implied reference that the voltage is relative to.

 

Try this idea: If cars going north are called a positive flow towards Detroit, then cars going south must be a negative flow towards Detroit. Changing the sign of a voltage only means it's going the other direction.

 

I don't have a serious problem if someone wants to think in loose terms that way --

Fair enough.
As you say, the actual force on the electron is generated by the electric field which is generated by the voltage gradient.
But I don't think it's particularly "loose" to think in terms of the voltage generating the force without having to mention the electric field (which is a mathematical construct with unknown physical structure), but to each his own.

 

I would understand if 0volts was half way between infinite or if positive voltage was protons and negative voltage was electrons but seeing as how protons don't move and positive/negative voltages can still be attracted to each other I doubt it.

OP was asking for a world of hurt when he started talking about electrons and protons...

 

OP was asking for a world of hurt when he started talking about electrons and protons...

Since the OP knows that the protons don't move, then I think he's okay.
You just have to know that the protons in the atom's nucleus provide the positive charge when the free electrons around the atom are moved by the voltage electric field to provide the negative charge at the opposite node.

 

The very statements "100v with an excess electrons," and, "100 V worth of missing electrons," are meaningless. Voltage is NOT a measure of charge! You need to study what the very concept of voltage is.

Heheh SIR, pretend I am an idiot, and try these explanations again.
---The way you explained that would have sent anyone spinning, there are much better ways to help someone who doesn't have the background knowledge to understand the concepts. You basically waste a lot of words, and worse may even cause a beginner to give up on a subject ( or at least ask someone else) when you are explaining in this manner...Do you recall any of your physics 101's ? Bet the prof didn't say it quite like that the first time he touched on it lmao.

 

We hope Mr. Bahn replies, but he has not been here for months.

I would go with@crutschow 's explanation in post #22 unless you are designing a vacuum tube.

 

Hello there! welcome to AAC!

Heheh SIR, pretend I am an idiot, and try these explanations again.

Would you happen to have a question you would like answered?

 

Old thread now locked.