Why do electrons flow in a wire?

[aychamo]

So, I guess I have two questions :)

The first, is why does electricity flow? I mean, what makes it go from one part of a wire to another?

And the second, do electrons flow "in" the wire, or on the surface of the wire?

 

[Integral]

Electrons are charged particles therefore they experience a force when in the presence of an electric field. It is this force which creates the flow in a conductor.

All free charge must reside on the surface of conductors, thus all free electrons are on the surface, thus the current flow is surface charge. There may well be more to it then that.

 

[aychamo]

What creates the electric field? I remember something from my second physics class about electric fields and the right hand rule. Is this what makes electrons flow form - to +?

 

[Gokul43201]

The electric field itself is created by a separation of charge - eg : electrodes of a battery. The field is created in a direction "generally" pointing away from the +ve electrode and towards the -ve electrode. So, if you dropped a positive charge into the region of this field, it would get pushed in that direction, ie. towards the -ve electrode. But electrons are -vely charged. So they are pushed in the opposite direction, ie. towards the +ve electrode.

This has nothing to do with the right hand rule, which is used when you throw a conductor into a magnetic field.

 

[JohnDubYa]

Electricty flows because one area of a circuit has too many electrons, and another area of the circuit doesn't have enough. Since electrons repel, they will travel from the former area to the latter. Their motion is called current.

Invoking electric fields to explain current is not going to help those that are struggling with fundamental concepts, in my opinion.

 

[jdavel]

Integral said, "All free charge must reside on the surface of conductors, thus all free electrons are on the surface"

Yikes! Want to try that again?

 

[Gza]

Free charge only resides on the surface of a conductor in the absence of an internal electric field(since the charges themselves arrange their configuration to make this true.) When free charge is moving through a wire, there is for sure an electric field acting, and we can't really say where the charge is at any time, except its in the wire moving. To get back to the question

Invoking electric fields to explain current is not going to help those that are struggling with fundamental concepts, in my opinion.

To me at least, the electric field is the fundamental concept. From integrating this field on a distance, we obtain the electric potential. If there is a difference in potential across two points in space, there is an electric field in between, and we call this difference the voltage. Now since there is a voltage across the + and - terminals of the battery, when this battery is connected to, say, a wire, what do you think will go on, based on what I said above?(aside from killing your battery)

 

[JohnDubYa]

Gza, I am not saying you are incorrect. But the electric field IS an abstract notion that a person struggling with the very fundamentals of electromagnetism is going to have a hard time understanding.

Exactly what IS an electric field? Try explaining that to the average Joe. If you revert to using the concept of charge attraction and repulsion (which the average Joe CAN understand), then why not just use those concepts and refrain from mentioning the field altogether?

Let me provide a simpler example.

Suppose you have a positively charged ion. And suppose nearby there is a free electron. You could invoke an electric-field explanation as to why the electron will migrate to the ion. You can say that the ion creates an electric field at the position of the electron, and the electron interacts with this field.

But do we have to make it so complicated? Why not just say that the electron is attracted to the ion because opposite charges attract? To me, that notion is every bit as fundamental as the electric field, and a Helluva lot easier to understand.

Besides, we created the electric field to provide a mechanism for determining the force acting on the electron. As far as introductory physics is concerned, it is a purely man-made construct, not a fundamental principle. I am not sure anyone has even settled on whether it really exists or is just purely mathematical. In the region between the two charges, is there really something there physically? I think the philosophers have to try and answer that question.

 

[krab]

thus the current flow is surface charge. There may well be more to it then that.

That would predict that the conductance of a wire is proportional to its radius. It's not; it's proportional to radius squared, or area. Current is confined to the surface in the case of high frequencies, when skin depth is small compared with radius. But for DC, current flows throughout the wire. Current is not after all excess charge; the wire is still neutral.

 

[krab]

What creates the electric field? I remember something from my second physics class about electric fields and the right hand rule. Is this what makes electrons flow form - to +?

+ and - in a sense is the electric field. They reflect the places where electric potential is resp. more positive and more negative. A potential difference from place to place is the same as saying there is an electric field.

 

[Math Is Hard]

hi - I am kinda barging in here but...
why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

 

[TALewis]

hi - I am kinda barging in here but...
why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

The *convention* for the direction of positive current corresponds to the direction of the flow of positive charges. However, in metal, the positive charges (protons), are fixed in place and cannot move. Only negative charges (electrons) are free to move. So, if electrons are inclined to move in one direction, protons would be inclined to move in the opposite. That's why, according to *convention,* current is opposite electron flow.

 

[Gza]

why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

The physics is the same reguardless of who is carrying the charge. Negative charge moving forward is completely analogous to positive charge moving backwards. When this stuff was being figured out, they had to go with one of the two, and guessed it was positive charge moving. It wasn't until the discovery of the Hall effect that we found out it was electrons that carry the charge. Funny thing is, that doesn't even matter when it comes to analyzing the behavior of a current in a circuit.

 

[Math Is Hard]

thanks, TA!

 

[Math Is Hard]

and thanks, Gza!

 

[JohnDubYa]

Essentially, the problem comes from the triboelectric chart. When two materials are rubbed together, one accumulates one type of charge, the other accumulates the oppositve type of charge. Unfortunately, when they decided to assign one of the materials as positive, they got it wrong. It turns out that the material they assigned as positive was the one that LOST the electrons. So when it was later discovered that the electrons are the particles that actually move during the process, it was too late.

In other words, science called heads, and the coin turned up tails. And we've been stuck ever since.

At least that is how I understand the story.

 

[Integral]

Integral said, "All free charge must reside on the surface of conductors, thus all free electrons are on the surface"

Yikes! Want to try that again?

Opps! I should know better then trying to make a quick post at the end a 12hr shift!

I like JohnDubYa's excess electron explanation.

When I learned circuits, by the US Navy,we were taught electron flow as the main current carrier, it is not clear to me why academia insists on positive current flow.

 

[ZapperZ]

When I learned circuits, by the US Navy,we were taught electron flow as the main current carrier, it is not clear to me why academia insists on positive current flow.

Does that mean then that (i) if I have a stream of protons moving in a particular direction, then the US Navy's definition of "current" points in the opposite direction of the proton flow, and (ii) the Navy redefined Maxwell equations, in particular, Ampere's Law, with an extra negative sign for the curl of B?

Zz.

 

[Doc Al]

nit pick?

That would predict that the conductance of a wire is proportional to its radius. It's not; it's proportional to radius squared, or area. Current is confined to the surface in the case of high frequencies, when skin depth is small compared with radius. But for DC, current flows throughout the wire. Current is not after all excess charge; the wire is still neutral.

I agree with everything said, except for a slight nit with with the last statement. I believe that when a wire is connected to a battery a non-uniform surface charge is created along the wire. It is this non-uniform surface charge that creates the electric field inside the wire that drives the current. The amount of surface charge needed is extremely small. Thus I think that the wire is very slightly charged. If I'm wrong, please correct me.

 

[Gokul43201]

hi - I am kinda barging in here but...
why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

Hmmm...so that really was your "borderline stupid quetion", eh ?

 

[jdavel]

Doc Al said, "Thus I think that the wire is very slightly charged. If I'm wrong, please correct me."

No, I think you're right on all counts. In fact, you can put a static charge on a wire by just touching it with one end of a battery and then removing it. Ignoring leakage, the wire now has a (very small) net charge.

 

[Math Is Hard]

Hmmm...so that really was your "borderline stupid quetion", eh ?

And I was quite satisfied with Motai's explanation of electrons swimming upstream against the current like salmon!

 

[Gza]

it is not clear to me why academia insists on positive current flow.

If I'm correct, this is done arbitrarily. The symmetry of Maxwell's equations under all transformations must be preserved, since nature doesn't insist on manmade coordinate systems. (who's to say what's left, right, +, -)? When getting down to the nitty gritty of solving the current in a ciruit, yes, by all means pick a coordinate system now and stick with it, making sure you remain consistent throughout the problem. I guess physicists just have a bright outlook on life, and chose positive to be the charge carriers. Some engineers I speak to who freak out about me talking about positive charge moving through wires demonstrate that they don't undertand the above-mentioned symmetry. Which is why I'm a physicist, and they're an engineer.

 

[BoulderHead]

I understood this confusion was traceable back to Benjamin Franklin, who simply took a guess that current flow was from positive to negative. Later, when it was determined to be otherwise the “damage” had already been done.

 

[robphy]

Electricty flows because one area of a circuit has too many electrons, and another area of the circuit doesn't have enough. Since electrons repel, they will travel from the former area to the latter. Their motion is called current.

Invoking electric fields to explain current is not going to help those that are struggling with fundamental concepts, in my opinion.

Besides, we created the electric field to provide a mechanism for determining the force acting on the electron. As far as introductory physics is concerned, it is a purely man-made construct, not a fundamental principle. I am not sure anyone has even settled on whether it really exists or is just purely mathematical. In the region between the two charges, is there really something there physically? I think the philosophers have to try and answer that question.

Avoiding the electric field may lead to problems later explaining why an induced current flows in a conducting ring in the presence of a changing magnetic field. [In standard texts, the [radial] electric field [of a point charge] is introduced to explain electrostatic attraction and repulsion of point charges. Later on, one learns that one can have [curly] electric fields without any charges present. Thus, we learn that the electric field has its own existence.]

Does that mean then that (i) if I have a stream of protons moving in a particular direction, then the US Navy's definition of "current" points in the opposite direction of the proton flow, and (ii) the Navy redefined Maxwell equations, in particular, Ampere's Law, with an extra negative sign for the curl of B?

Zz.

Since protons are positively charged, the electric current (defined by convention as the flow of positive charge) flows in the same direction of the protons' flow.

Ampere's Law still reads (modulo your choice of units) \vec\nabla\times\vec H = \vec J + \frac{\partial \vec D}{\partial t}
http://wwwppd.nrl.navy.mil/nrlformulary/maxwells_equations.pdf

 

[Integral]

Avoiding the electric field may lead to problems later explaining why an induced current flows in a conducting ring in the presence of a changing magnetic field. [In standard texts, the [radial] electric field [of a point charge] is introduced to explain electrostatic attraction and repulsion of point charges. Later on, one learns that one can have [curly] electric fields without any charges present. Thus, we learn that the electric field has its own existence.]

Since protons are positively charged, the electric current (defined by convention as the flow of positive charge) flows in the same direction of the protons' flow.

Ampere's Law still reads (modulo your choice of units) \vec\nabla\times\vec H = \vec J + \frac{\partial \vec D}{\partial t}
http://wwwppd.nrl.navy.mil/nrlformulary/maxwells_equations.pdf

I think you missed the point of ZZ's post, this is sort of a back handed explanation to me of why academia used positive flow convention. The Navy, used to, and probably still does, teach NEGATIVE current flow to Technicians. This is a bit more physical for the SPECIAL case of current flow in an electronics circuit, where electrons are the current carrier, in spite of the current definition given by Maxwell and and Ben Franklin. We were made aware that there was also a positive current flow convention. Hard not to since we were always flowing against the arrows in the schematic of a transistor. This is the first time that I have been made aware of the obvious, that is, negative current flow is not the same current as defined by Maxwell.

 

[ZapperZ]

Since protons are positively charged, the electric current (defined by convention as the flow of positive charge) flows in the same direction of the protons' flow.

Ampere's Law still reads (modulo your choice of units) \vec\nabla\times\vec H = \vec J + \frac{\partial \vec D}{\partial t}
http://wwwppd.nrl.navy.mil/nrlformulary/maxwells_equations.pdf

How can you get away with saying that? If the Navy DEFINES current flow in the SAME direction as the flow of negative charges, then if I have a flow of positive charges and I ALSO use that direction as the flow of current, don't you think there is a BIG, major screw up here waiting to happen?

Now use the right-hand rule (as defined mathematically when we do a curl of a vector field) for a straight wire, for example. You will notice that once you define how you want the direction of current to move, you will get the OPPOSITE direction for the direction of the H field vector. If I define current flow to be the direction of positive flow, this will produce an opposite field than if I define the direction of negative flow as the direction of current.

I will express my amusement that this has become such a complicated issue. I guess that having to deal with the transport problem in solids, I truly find such issue rather trivial, very much like defining where the "zero" of a potential is. The fact that all our "measurement" can easily be "renormalized" to a different gauge to transform an "electron flow" into a "positive hole flow" without having to make any significant changes to our laws means that maybe we're wasting time on something that does not have much significance. Is there really a major conceptual problem with defining current flow as the flow of positive charge? If there is, then there should be a similar conceptual problem with defining electron charge as "negative".

Zz.

 

[Integral]

I will express my amusement that this has become such a complicated issue. I guess that having to deal with the transport problem in solids, I truly find such issue rather trivial, very much like defining where the "zero" of a potential is.

You are absolutly correct. It is a trivial issue. It seems that it is you who is the most concerned with it. Why bother?

Read my reply to robphy.

 

[robphy]

I see that I missed (glossed over) the Navy convention for current.

 

[ZapperZ]

You are absolutly correct. It is a trivial issue. It seems that it is you who is the most concerned with it. Why bother?

Read my reply to robphy.

I think now it is you who missed the point. I'm concern when people decide to change the convention on how we define things for no reason other than a matter of "taste". It is one thing to change how we define things when there is a valid reason for it. It is another simply because it didn't "feel" right. That is why I asked you if Ampere's law is defined differently when you are taught to define current as the direction of electron flow in a conductor.

What I find "trivial" is the apparent difficulty in having the direction of current flow opposite to the direction of negative charge flow. Why is this even an issue?

Zz.

 

[Integral]

It is an unnecessary layer of formality. A working electronics tech does not have to know Maxwell's equations, and when teaching the principles to High School grads most of whom have not had Calculus, thus you really need to cut to the chase. The training is made very effective by making it well known that you are learning ELECTRON flow while others speak of a positive current flow, or the flow of where the electrons have been. I cannot see why you would teach it any other way to people who are not accustomed to abstract concepts. Electron flow is completely physical, while positive current flow always has no answer to the simple question, what is flowing.

 

[ZapperZ]

It is an unnecessary layer of formality. A working electronics tech does not have to know Maxwell's equations, and when teaching the principles to High School grads most of whom have not had Calculus, thus you really need to cut to the chase. The training is made very effective by making it well known that you are learning ELECTRON flow while others speak of a positive current flow, or the flow of where the electrons have been. I cannot see why you would teach it any other way to people who are not accustomed to abstract concepts. Electron flow is completely physical, while positive current flow always has no answer to the simple question, what is flowing.

Ok then, let's go with the situation where you have you have people who are "not accustomed to abstract concepts". Under what condition here would you expect that they would KNOW that what they are measuring is an "electron flow"? Without telling them about "conduction electrons", etc, what device or measurement that they would be making that somehow will reveal this fact?

I will put it to you that in their situation, there are none! Whether it is electron that's moving, or positive charges that's moving, a typical electrical measurement cannot tell the difference! (If they're doing Hall effect measurement, then I'd say they should have even LESS of a problem with positive current flow). So then, why bother with changing the convention? In fact, I would assert that one is potentially introducing a source of confusion should any of them decide to actually look up standard texts.

Zz.

 

[Integral]

ZZ,
I am not a complete idiot, nor was anyone else that I was in training with. In fact the men and women selected for the Electronics programs are generally chosen due to high scores on intelligence tests. Most are familiar with the idea of an electron.

Once again ELECTRON FLOW IS COMPLETELY PHYSICAL. IT IS WHAT IS HAPPENING. It makes very good sense to TEACH THE REAL DEAL for those who will be dealing with NOTHING else. And if those being taught are bright enough to see the difference. This approach simply avoids unnecessary class time explaining why you chasing a non existent particle. If you think there would not be time wasted having to explain such issues away then you certainly have not had to deal with bright but uneducated students.

 

[ZapperZ]

ZZ,
I am not a complete idiot, nor was anyone else that I was in training with. In fact the men and women selected for the Electronics programs are generally chosen due to high scores on intelligence tests. Most are familiar with the idea of an electron.

Once again ELECTRON FLOW IS COMPLETELY PHYSICAL. IT IS WHAT IS HAPPENING. It makes very good sense to TEACH THE REAL DEAL for those who will be dealing with NOTHING else. And if those being taught are bright enough to see the difference. This approach simply avoids unnecessary class time explaining why you chasing a non existent particle. If you think there would not be time wasted having to explain such issues away then you certainly have not had to deal with bright but uneducated students.

You still have neglected to tell me where is the conceptual difficulties in having the definition of current as the direction of positive charge flow, and where will they actually encounter the situation where what is "flowing" actually makes a difference.

I, however, have pointed out several instances, such as Ampere's law, where you have to literally modify the curl of B to make your definition consistent. What about Lenz's law? Did you have to reverse the direction of the induced field there also? I see several other instances where this can lead to layers of confusion. If these are really very smart students, then they should never have any conceptual difficulties in accepting how current is defined, should they? Then as I've stated earlier on, I do not see a clear reason why a new definition for current has to be introduced in the first place.

Zz.

 

[Integral]

Once again to justify positive current flow you must introduce layer about layer of complications. Why do I need any of that to understand that electrons flow from the negative terminal to the positive? This is simply the easiest and most effective way of teaching what needs to be taught. Keep in mind that the Navy, in a matter of a few weeks turns kids with a High School education into very capable technicians able to maintain and repair complex electronics which are essential to the defense of the nation.

Consider that it takes a community college 2 years to get to a similar point. (My total Navy classroom training lasted less then 6 months).

Yes, I did get some bad concepts from Navy training which had to be unlearned (perhaps more difficult, then if I was starting with a fresh slate) when I encountered a real E&M course.

 

[ZapperZ]

Once again to justify positive current flow you must introduce layer about layer of complications. Why do I need any of that to understand that electrons flow from the negative terminal to the positive? This is simply the easiest and most effective way of teaching what needs to be taught. Keep in mind that the Navy, in a matter of a few weeks turns kids with a High School education into very capable technicians able to maintain and repair complex electronics which are essential to the defense of the nation.

Consider that it takes a community college 2 years to get to a similar point. (My total Navy classroom training lasted less then 6 months).

Yes, I did get some bad concepts from Navy training which had to be unlearned (perhaps more difficult, then if I was starting with a fresh slate) when I encountered a real E&M course.

Honestly, I don't mean to be difficult. But exactly where in such a class does a student actually DISCOVER that it is the electron that actually "flow"? A voltmeter, ammeter, etc, tells nothing on this. If you just say current flows from positive potential to negative potential of a battery, in what way as far as an electronics measurement goes, can a student contradict that? If one is ignorant of the band structure of a metal, where does one know that it is the conduction electron that actually "flows"?

And how does using the conventional current flow actually introduced layer and layer of complications? I think electrical engineers, of all people, are the ones who really do not care (or even believe?) in "electrons" and electron flow. Such details are irrelevant. So why would there be any conceptual difficulties in using the conventional definition of current?

Zz.

 

[Integral]

Once again, if you simply concentrate on WHAT IS HAPPENING it is simple, and cannot be to far wrong. The only incorrect concept was in the fundamental operation of inductors (the idea of a change in flux).

I am somewhat put off by your attitude because I have seen how effective Physics TAs are, or are NOT, is perhaps a better description. (I have a great deal more experience with them then most!) Yes, there is the occasional one that can and does teach something. So it is not clear to me why you are so against something that works. Your experience is with a system which treats teaching as a necessary evil. A distraction from your true goals which is research of one form or another.

The Navy on the other hand has a definite goal, to teach electronics, the resulting training is effective and meaningful. It is to bad that you cannot appreciate this, seems excess theory has clouded your vision of the rest of the world. Maxwell's concepts are essential at your level, they are not when you are on board ship and the radar is down.

 

[ZapperZ]

Once again, if you simply concentrate on WHAT IS HAPPENING it is simple, and cannot be to far wrong. The only incorrect concept was in the fundamental operation of inductors (the idea of a change in flux).

Sorry, but how do you know what is happening? How can you tell that it is an "electron flow" when you measure anything in a circuit? That is my question. If people who understand solid state physics don't tell you about conduction electrons, where exactly do you discover what exactly is "happening"? And what about those semiconductors that have positive holes as the majority charge carrier? What direction is the current flow there?

I am somewhat put off by your attitude because I have seen how effective Physics TAs are, or are NOT, is perhaps a better description. (I have a great deal more experience with them then most!) Yes, there is the occasional one that can and does teach something. So it is not clear to me why you are so against something that works. Your experience is with a system which treats teaching as a necessary evil. A distraction from your true goals which is research of one form or another.

But that is the same question that I asked you. Why are you so against something that works? The definition of current as adopted via convention WORKS! In fact, it is universally adopted, even with people who don't use English.

BTW, in what way is my "experience is with a system which treats teaching as a necessary evil"? Where did I convey such nasty position?

The Navy on the other hand has a definite goal, to teach electronics, the resulting training is effective and meaningful. It is to bad that you cannot appreciate this, seems excess theory has clouded your vision of the rest of the world. Maxwell's concepts are essential at your level, they are not when you are on board ship and the radar is down.

As an experimentalist, I care only in what has been demonstrated to work. So you will understand that I find it ironic of your accusation that "excess theory" has clouded my vision. I do not understand where the conventional definition of current would not work when a ship radar is down? 2 weeks ago I spent 4 days at the NRL. We spent time working on RF systems and pick-up antennaes. No where in such environment did I encounter problems with the electronics, or even communication with other engineers just because I adhere to the conventional definition of what current is. So please explain to me how adopting a conventional definition of current would not help in working and repairing a radar.

Zz.

 

[zoobyshoe]

The reason the concept of positive to negative current flow is confusing is because people are also taught that electrons flow from negative to positive:

hi - I am kinda barging in here but...
why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

Students are started off learning about static electricity: you rub electrons off one thing and leave atoms that are electron-hungry, so to speak on another. When electron rich things meet electron deficient things the electrons move from excess to deficiency.

Later, though, the confusion of positive current is thrown at you. Since this is really a relic of a more ignorant time, I agree with Integral it shouldn't be taught.

The fact no measuring device will reveal the actual direction of the current might be a case for ignoring the fact the convention is backward, except that the contradictions in the different stages of learning are unnecessarily confusing.

 

[chroot]

zooby,

The Hall effect will in fact demonstrate whether the moving charge carriers are positive or negative.

- Warren

 

[zoobyshoe]

zooby,

The Hall effect will in fact demonstrate whether the moving charge carriers are positive or negative.

- Warren

Right. I didnt phrase that well. I should have said "The fact that commonly used measuring devices don't reveal the direction of current flow might be a case for ignoring the fact the convention is backward, except that the contradictions in different stages of learning are unnescesarily confusing."

 

[BobG]

hi - I am kinda barging in here but...
why does the current move in the opposite direction that the electrons are moving? that's what my book states, but it doesn't explain why. thanks!

My first training in electricity was very similar to Integral's - almost identical, except for one key point. My training was vastly superior to Integral's because it was given by the Air Force instead of the Navy.

There is actually a very good reason for the discrepancy.

How fast does electricity move? In other words, from the time you flick the light switch, how long does it take for the light to turn on?

How fast do the electrons move? In other words, from the time you crank your starter, how long does it take for an electron to move from the battery to the starter?

I was once told it takes about three days for an electron to move from the battery terminal to the starter (plus or minus depending upon how long the cable is). I've never actually checked that, since it is kind of irrelevant. But, the point is that the speed of electricity and the speed of electron movement aren't exactly the same thing.

It's more like a bunch of students sitting at a row of desks with the back desk empty. If you have 10 seats in the row, and the student at desk #9 moves back one seat, the 'hole' has moved up one seat. Student at desk #8 moves back, the 'hole' moves up one. And so on and so on. The end result is that , over certain amount of time, the 'current' has moved the entire length of the row, while each 'electron' has only moved one desk.

The 'effect' of electricity is moving one direction while the 'cause' is moving the opposite.

 

[zoobyshoe]

No. Drift velocity and the speed of the emf is a different can of worms. Not the same as the direction of current flow. The fact that the actual physical progress of the electrons is much slower than the impulse of power they produce down the whole line when they move is a separate issue.


The discrepancy in the direction of current arises, pure and simply, from a time when no one knew which direction the current flowed and took a stab at a guess:

"...Electrons can now flow through the complete circuit; however we usually visualize a flow of positive charges in the opposite direction and call that the current. Thus we use this imaginary positive current for purposes of circuit analysis, keeping in mind that the true current is largely that of electrons, and in the opposite direction."

-Physics Concepts and Consequences
Raymond L. Murray
Grover C. Cobb
©1970 by Prentice-Hall, Inc.,Englewood Cliffs, N.J.
Library of Congress :79-118661

I don't believe the concept of "positive hole flow" came into use till the invention of semi-conductor devices, when someone decided it would be a useful tool to understand how these work.

 

[Math Is Hard]

I was once told it takes about three days for an electron to move from the battery terminal to the starter (plus or minus depending upon how long the cable is). I've never actually checked that, since it is kind of irrelevant. But, the point is that the speed of electricity and the speed of electron movement aren't exactly the same thing.

They're not?? I had no idea.

The end result is that , over certain amount of time, the 'current' has moved the entire length of the row, while each 'electron' has only moved one desk.

The 'effect' of electricity is moving one direction while the 'cause' is moving the opposite.

Oh -I think I see what you mean now. Clever analogy!

 

[Integral]

My first training in electricity was very similar to Integral's - almost identical, except for one key point. My training was vastly superior to Integral's because it was given by the Air Force instead of the Navy.

This is a whole different topic for debate! Flyboy