# Conventional vs Electron flow

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#### Wolframore

Joined Jan 21, 2019
2,582
Positive and negative are just arbitrary words is what @nsaspook is getting at... don't get stuck on the concept. Current can flow in either direction - positive current flows in electrolytes, electron flows happen in copper wires... whats important is that current flows and you stick to one way to keep your calculations consistent direction doesn't really matter.

#### electricalengineer3

Joined Feb 6, 2020
172
Positive and negative are just arbitrary words is what @nsaspook is getting at... don't get stuck on the concept. Current can flow in either direction - positive current flows in electrolytes, electron flows happen in copper wires... whats important is that current flows and you stick to one way to keep your calculations consistent direction doesn't really matter.
Yeah I totally see everyone's point in what they're saying. The one thing I am looking for is just to see problems worked out both ways just to finally put it to rest and understand it mathematically.

#### electricalengineer3

Joined Feb 6, 2020
172
I don’t understand your problem. You can assign the the direction of the currents any way you want. You can have two batteries in your circuit and have one of them with the current coming out of the +terminal and the other with the current coming out of the - terminal and the solution will be the same except for the signs of the currents.

If you are getting different numbers, then you set up the equations wrong somewhere.

Bob
So if we were to use electron flow as convention, are you saying it would just be negative? Isn't that the same as our normal convention. A negative current out of the - side is just a normal current out of the plus side

#### schmitt trigger

Joined Jul 12, 2010
515
The only electronic circuits which are perhaps easier to understand with electron-flow current convention, are vacuum tubes.

#### electricalengineer3

Joined Feb 6, 2020
172
The only electronic circuits which are perhaps easier to understand with electron-flow current convention, are vacuum tubes.
I get that it doesn't matter as ultimately the electrons will get there either way you look at it. I just want to see a mathematical example of a few problems using both conventions to see how it works.

#### nsaspook

Joined Aug 27, 2009
10,895
Last edited:

#### electricalengineer3

Joined Feb 6, 2020
172
You think there's a pdf available?

#### nsaspook

Joined Aug 27, 2009
10,895
You think there's a pdf available?
There are plenty of examples online, look above at my edited post.

#### electricalengineer3

Joined Feb 6, 2020
172
There are plenty of examples online, look above at my edited post.
Gotcha thanks for that, I am going to try and find some examples with resistor combinations to really try and figure it out

#### electricalengineer3

Joined Feb 6, 2020
172

#### WBahn

Joined Mar 31, 2012
28,165
Yes I understand that. I am hoping to see an example of how it doesn’t matter and the technique for both ways. I can’t just say oh it doesn’t matter and understand it that way, I am hoping to see a 1to 1 comparison using both conventions.
If you understand it, then what is preventing YOU from taking a problem and solving it both ways? Then, if something is unclear, present both analyses and describe what you find troubling. Then we can help you clear up your confusion.

#### WBahn

Joined Mar 31, 2012
28,165
So why would the electron current be entering the minus side of the resistor. Also, would the current be coming out of the minus side still be listed as 2A and not -2A?
Herein is where a huge part of the problem lies with all of the electron-current acolytes.

These folks insist that since the physical charge carries (in typical) electric circuits are electrons and since these flow from lower potential to higher potential (e.g., from negative to positive), that the direction of current shown on a diagram should properly be from negative to positive. But then they almost universally want to claim that the electrical current in that direction is a positive quantity, and it's not.

As an example: Connect a 10 V source to a 5 Ω resistor. Using electron-current, what is the current flowing from the negative terminal of the battery through the resistor and toward the positive terminal?

Past any given point in the circuit there are approximately 12.5 x 10^18 electrons/second flowing in the specified direction, so

I = 12.5 x 10^18 electrons/second

But to express this in amperes, you need to multiply this by the charge of an electron.

I = (12.5 x 10^18 electrons/second)·(-1.602 x 10^-19 C/electron) = -2A

So, using electron current, the current flowing out the negative terminal is negative. But the electron-current acolytes all insist that it is positive, because they fail to distinguish between the flow of charge carriers and the flow of the charge that they carry. In doing so, they introduce a sign error and the result is that they have to further introduce magical mystery minus signs throughout their work, which they do largely without thinking about it.

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#### electricalengineer3

Joined Feb 6, 2020
172
If you understand it, then what is preventing YOU from taking a problem and solving it both ways? Then, if something is unclear, present both analyses and describe what you find troubling. Then we can help you clear up your confusion.
Fair enough. One thing that is confusing is for the electron flow convention, if Dq/dt is defined as current why wouldn’t the flow of negative q’s aka electrons be a negative current? That’s one of my first issues.

#### WBahn

Joined Mar 31, 2012
28,165
Of course not. Choosing electron current does not make your battery’s positive terminal negative. The voltages and polarities are not affected.

Bob
Actually, this is exactly what SHOULD happen in order to yield a consistent system. The electron-flow crowd, without realizing that they are doing it, insist on redefining the charge of an electron to be a positive quantity -- that is the only way they can claim that a positive current, expressed in coulombs per second, flows out of the negative terminal of a battery and into the positive terminal (in a typical circuit). The consequence of this redefinition is that all of the battery voltages would get reversed. But they can't recognize that they are doing so and will, in fact, adamantly insist that they aren't, so they work with voltages defined using negatively-charged electrons and current defined using positively-charged electrons with the result that they have to throw around a whole slew of magical mystery minus signs to make their approach work.

#### WBahn

Joined Mar 31, 2012
28,165
Fair enough. One thing that is confusing is for the electron flow convention, if Dq/dt is defined as current why wouldn’t the flow of negative q’s aka electrons be a negative current? That’s one of my first issues.
It most definitely should -- but the people that cling to electron-flow generally work at a level involving a much lesser degree of mathematical rigor. Electron flow is something that is easy for people to visualize compared to the more abstract notion of charge flow. They apply memorized equations to small pieces of problems and then use reasoning, not mathematical modeling, to put them together to get an answer (and this is when they apply, without realizing they are doing so, the magical mystery minus signs).

As soon as you start applying rigorous mathematical modeling to a problem, the electron-flow approach (as nearly universally practiced) falls apart.

#### WBahn

Joined Mar 31, 2012
28,165
So is a voltage source labeled in such a way that the plus side (higher potential) is labeled for the effect on positive charge carriers. Therefore, a positive charge at the top of a battery feels high potential and flows to the negative. Wouldn't it make more sense for electrons to be positive charge and be at the plus side of the battery and flow to low potential since they are actually what is carrying the charge in a wire?
To do that, we would have to relabel all the batteries in the world. The definition of electric fields and potential (voltage) would be unchanged, but the polarities that we would arrive at would be flipped since they are defined in terms of their effects on positive test charges. What we now call the positive terminal of a battery we would determined to be the negative terminal and vice-versa.

If we lived in a universe that was filled with particles having positive mass and negative mass, we would have the same issues we have when trying to comprehend electrical properties. However, if that were the case, we would also have a very intuitive feel for working with them as they would constitute an inescapable part of our daily experience. But we don't - we live in a macroscopic world in which our primary notions of concepts like potential energy come from objects interacting in a gravitational field in which all objects have the same polarity, so we tend not to make a distinction between the object and the polarity of it's mass. We then want to carry forward that mindset to the electrical world in which those distinctions are important.

#### electricalengineer3

Joined Feb 6, 2020
172
It most definitely should -- but the people that cling to electron-flow generally work at a level involving a much lesser degree of mathematical rigor. Electron flow is something that is easy for people to visualize compared to the more abstract notion of charge flow. They apply memorized equations to small pieces of problems and then use reasoning, not mathematical modeling, to put them together to get an answer (and this is when they apply, without realizing they are doing so, the magical mystery minus signs).

As soon as you start applying rigorous mathematical modeling to a problem, the electron-flow approach (as nearly universally practiced) falls apart.
Yeah I mean when we look at the actual definition of current (flow of charge with respect to time), electron flow should be noted as a negative change in charge going out of the negative terminal of a battery. This is mathematically equivalent to positive charge coming out of the positive. This leads me to conclude that electron flow is no different then what we already use. Obviously this is not the case. But what do you mean the magical mystery minus signs? I don't see how negatives could come into play if they are just assuming negative charge moving is positive.

#### BobTPH

Joined Jun 5, 2013
6,285
For instance, if you consider electron flow as a positive current, then current flowing through a resistor causes a voltage increase instead of the more intuitive voltage drop.

Bob

Joined Jan 15, 2015
7,135
If you assume current flow, its direction is from the positive end to the negative end.

If you assume electron flow, it's direction is from the negative end to the positive end.
A long time ago when I think dinosaurs roamed the earth, well maybe not quite that long ago but anyway I learned it and was taught electron flow, before solid state diodes were popular I was taught that for example on a diode vacuum tube like an old 5U4G that when the filaments were hot electrons "cooked" off or were emitted from the filament which served as a cathode and flowed to the plate which served as an anode. Thus in the case of a solid state diode I was taught electrons flowed into the arrow. A little later I learned about hole flow? So do electrons really flow or do the holes the electrons occupied actually flow? Does it really matter and if it does it likely only matters to a select few. Those with obsessive compulsive disorder need not apply.

During The Second World War (WW-II) there was a saying following the US taking The Philippine Islands back. The saying went "By the grace of God & the help of the Marines McArthur has returned to the Philippines. I figure by the grace of God and current flow I survived a 45 year career working in electronics. I can honestly say over an entire career and endless formula that never once did it matter which way the electrons flowed. There was never any call for it. When I walked away upon retirement I told my juniors that my entire career was an "E" Ticket ride and that "electronic stuffs are been very, very gud to me" and let it go at that.

Forum discussions on this subject never seem to go well and my simple observation is toss in a few OCD types and things go South real quick. Since I don't have a dog in the race I just grab a snack and watch. Become familiar with the theory behind If you assume current flow, its direction is from the positive end to the negative end and If you assume electron flow, it's direction is from the negative end to the positive end and move along.

Ron

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