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Which way does it flow?

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oasisbhrnw

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Hi all,

I am new to electronics and have just started reading about it. I have read some conflicting information on which way electrons flow from the poles of a battery. Which way do they flow? From the negative side to the positive side, or vice versa?

Thanks.
 
Hi,

Electron Flow goes from negative to positive. When these electrons move, they leave a 'hole' where they used to be. The 'hole' flows from positive to negative.

It doesn't really matter which you use. You will notice that many circuits you will see are arranged with the 'positive' at the top of the circuit, and 'negative' at the bottom as if gravity has some influence over the flow.
 
Do you have to ever take it into account? For instance, when it comes to RC time constants? Does it matter in which order you put the resistor and the capacitor?
 
To help remember, think of it this way:
Electrons have a negative charge.
The battery + terminal has a positive charge.
Opposite charges attract.
Thus the electrons will be attracted to the positive termnal and the electron flow is from the negative terminal to the positive terminal.

But just to confuse things, as Bill's reference shows, in electronic design we typically use current flow, which is defined as going from positive to negative. As long as you are consistant in all you calculations it doesn't make any difference.

They had a 50% chance of getting it right when they first arbitrarily designated the direction of current flow (before anyone knew about electrons) and they got it wrong.
 
Do you have to ever take it into account? For instance, when it comes to RC time constants? Does it matter in which order you put the resistor and the capacitor?
No. There may be other reasons to be concerned about the order of a resistor and capacitor, but not as far as electron versus current flow.

You don't normally have to be concerned about it in the macro world of resistors, capacitors, inductors, transistors, etc. But if you are designing the semiconductor device itself (or in old times, a vacuum tube), you then have to deal with the electron flow.
 
Do you have to ever take it into account? For instance, when it comes to RC time constants? Does it matter in which order you put the resistor and the capacitor?

I would say you never have to take it into account for designing or repairing circuits - I consider current flows from the top of the circuit down to the bottom, I don't care if it's electron flow, conventional current flow, or bananas.
 
allaboutcircuits.com has a very good article on this i think its in the resistance notation part. check it.
 
Hi,

Electron Flow goes from negative to positive. When these electrons move, they leave a 'hole' where they used to be. The 'hole' flows from positive to negative.

It doesn't really matter which you use. You will notice that many circuits you will see are arranged with the 'positive' at the top of the circuit, and 'negative' at the bottom as if gravity has some influence over the flow.

Very good explanation, they flow from negative to positive. Thats what I first studied in school.
 
There may be other reasons to be concerned about the order of a resistor and capacitor, but not as far as electron versus current flow.

This is slightly off topic, but since it's been brought up, where would this matter? In a series string of one resistor and one capacitor from some node to ground, would order ever matter? Say from the compensation node of a switching regulator (e.g. LM2587T)?
 
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