AC flowing through a cap. What actually happens?

[BrownOut]

Hello again,

Jony:
Im sure Brownout didnt see that one
and i quote:
"Maxwell's solution was to say that a displacement current was flowing, but of course we now know that is not the case".
And now there we have an MIT professor stating out right that Maxwell was wrong, wrong about that ONE thing.
It doesnt mean that we ignore the idea of displacement current or that we necessarily have to apply that to every case, but it does mean we cant take it too seriously in the case of the vacuum capacitor.

Ratch:
Thanks again, i'll take a look.

And I"m sure MrAl never watched the University of Illinois video I posted, that showed Maxwell was right. Not only did the professor say displacement current was flowing, but diagrammed how it is a continuation of conduction current. Looks like Ratchet's textbook confirms it too.

I can't watch the video from work. I'll watch later.

 

[MrAl]

This is how you can tell someone is parsing language. Notice the false logic; "they don't say it's real." Of course they don't say it isn't real either, which is more important, because something that's real doesnt' need to be validated. If it's real, then it's real. If they thought it wasn't real, then they would say so, and not even publish all the details of it. And clearing up a contradiction proves that it's mathematically sound ( remembering that mathematics is the foundation of science ) and leans more towards confirmation than denial.

I've seen numerous sites now that state definitively that in the vacuum capacitor the displacement current is not real, and Professor Viken put it in better words, "not physical". That doesnt mean that the field isnt there, but there's no real current. The only way you can say that there is real current flow is to say that the vacuum of space contains random charges and i dont think that is the case and i might be able to prove that.
You probably dont agree as usual, but that's ok we might be able to make some real headway soon though, at least in the case of the vacuum capacitor.

 

[BrownOut]

I've seen more sites that shows displacement current flowing, and the University of Illinois professor's lecture shows it too, as does the other youtube video. I'm sure Physics textbooks and lectures wouldn't spent so much time on something that's not real. Nobody has yet to show that it can't be quantified and measured, and anything that can be quantified and measured has to be real.

 

[MrAl]

Hello again,


Well in the vacuum capacitor it is a special case i believe. You dont have to agree, that's sometimes what it means to be human
BTW did you solve Ampere's equation, the one with curl H on the left side? That's not the one i was talking about but that's ok if you did, so did you?

But you know it's time for some authoritative input on this matter, so i've asked Professor Viken to join the discussion. If he joins in we can ask him about the video and exactly what he meant by some of the things he talked about in the videos. He's a very knowledgeable guy with a lot of knowledge in many areas of science so i would suggest we respect that and listen carefully to what he has to say.

 

[killivolt]

Hello again,


But you know it's time for some authoritative input on this matter, so i've asked Professor Viken to join the discussion. I

I have only read the first 4 post's then again on Page 18, nothing like skipping to the end. I have only followed the recent discussions ultimately to arrive at the right moment

Excellent.

 

[BrownOut]

If he really is smart, he'll stay far away from this group, heh!

 

[MrAl]

If he really is smart, he'll stay far away from this group, heh!

Really? Why do you say that?
I'll watch the video you pointed out if i can find it, thanks.
Note: cant find it, can you post a link here now? I'll check it out.

 

[BrownOut]

All this time and effort and you didn't even view the short video I posted? Tsk, tsk... What a waste. It's there, you just gotta find it.

Here is a good discussion about the differences in conduction and displacement current, and it uses the proper terminology to differentiate the two. Of course, a couple people here will either ignore it, or try to link some opposing view, but if there is anyone else left reading at this point, you should get a sense that when some write nonsense, like "current + displacement current cannot equal current..." baloney, they are ignoring the distinction between the two, and/or purposfully trying to confuse the subject.

You have to scroll down to Chpater 12. This is also a Shaum's outline on Physics. Displacement Current.

EDIT: Scrolling doesn't seem to be required. When I clicked, it landed right on the discussion.

 

[MrAl]

Hello again,

Sorry Brownout but i just dont see how that link changes anything. They even state that there is no conduction current between the plates, just a field. But we already knew that so i dont understand your point here.

What it is starting to look like is that, for this one case with the vacuum capacitor at least, that the displacement current is NOT there in general, but as soon as something that contains free charge enters between the plates a true displacement current appears. This might be simple to prove by thinking about the space between the plates. With nothing in between the field is free to exist as it pleases, but this changes completely even with the addition of a small amount of material that contains free charge.
To state this a different way, the problem seems to boarder on the edge of reality where the propensity for something to be there is there, but not that actual something yet.

But anyway, do you at least agree that a changing electric flux can produce a magnetic field all by itself without anything else? This is pretty much a global belief i think but i'd like to hear your input.

I might have a way to prove something here soon, whichever way it goes we'll have to see i guess.

BTW you dont have to keep getting sarcastic. I looked through the whole thread and could not find that link you said i didnt see.

 

[BrownOut]

They state a displacement current flows between the fields, explicitly. A direct quote "We define a current through A2 ( between the plates in the accompanying diagram ) to be iD = jDA = I" There can be no mistake they are clearly talking about displacement current: iD=jDA=I. I can't help anyone living in denial of what is in plain print. At least some other readers can look, read and understand that the link speaks explicitly of displacement current, develops the analysis, shows how it's measured and gives examples. It doesn't get more clear than that.

A displacement current exists between the plates of the air capacitor whenever the E filed is changing, ie whenever current is flowing in or out. As shown on many analysis and many videos that has been linked to this discussion, the displacement completes the circuit, per Kirchoff's current law. Of course, it decays as the charge flow decays, as in the DC case, as would be expected.

But anyway, do you at least agree that a changing electric flux can produce a magnetic field all by itself without anything else? This is pretty much a global belief i think but i'd like to hear your input.

More accurately, a changing electric flux does have an associated magnetic field.

BTW you dont have to keep getting sarcastic. I looked through the whole thread and could not find that link you said i didnt see.

Who's getting sarcastic? I expect anyone who's engaged in the discussion to be an adult, and look at the links the members take the time to put up. I put it up days ago, and you obviously didn't look. At least you looked at the link today, probably the first one I've posted.

 

[MrAl]

Hello again,

Brownout something just doesnt jive with you, as usual. You'll take three or more posts to complain that someone hasnt looked at your link but still not post it here as i asked. Instead you posted something else, then still complain. I also didnt realize that people are not adults if they dont look at your links. Another obvious implication that doesnt truely apply. I have a feeling you can not distinguish between a theory and a proof.

I think i'll wait for the professor before i comment any more, unless i find something else out in the mean time.

 

[BrownOut]

Not surprisingly, you misquote me again. Yes, I epxect people who are engaged to be adult enough to read the links that members take the time to put up. I've read every document and watched every video linked to this long, long thread. That's what someone who wanted a serious discussoin would do. I don't think that's expecting too much, but apparently it is. I know perfectly well the difference between theory and proof, but I'm dubious of your understand of the same. I've shown over and over how practice validates theory, but you choose to ignore what I've written, and instead argue points I never made. It started out as an interesting discussion, but has become pretty much a waste of time.

About the link, it would take me the same effort to go back and find it as it would take you. And I"m sure you can if you put in the effort.

 

[Mr RB]

...
MrRB:
Not everyone is in agreement that current goes through a vacuum capacitor though. In fact, the general answer to that question is "no" because what does, if anything, goes through a vacuum capacitor, may not be considered to be something that is actually physical.
Consider a B field acting on a charge. The B field is an influence that moves the charge and thus creates a current as defined by the standard dQ/dt. But what happens when there is no charge there to move, how can we possibly have a current like this? This answer is that we dont, we just have a field, and a field is not considered a current. A field can cause a current yes, but it needs something else to work with it or else it's just a field.
See there are two views here:
1. The internal view, and
2. The external view.
The external view is used in circuit analysis to simplify the equations. This views current as flowing through a capacitor.
(snip)
...

I agree with everything you have said Mr Al. I also have no problem with the concept that any particular electron that goes into a capacitor may not come out the other side.

In the case of your vacuum capacitor I would think it is highly unlikely for any single electron to go "through".

But when I originally used the word CURRENT it was with respect to the term itself, which is largely conceptual. This is an electronics forum and in electronics CURRENT is a very standardised concept that goes through things. In your circuit simulator software if there is one amp going in capactor legA and also out of legB that it is "through" and will be simulated as "through"... the same as for any component.

If you want to say that "electrons don't actually go through the capacitor" that may have credence as a statement. But you can't go on an electronics forum as Ratchit did and make a global sweeping statement that CURRENT does not go through a component. CURRENT going through a component can be measured with an ammeter, it can be simulated in a circuit simulator and calculated as vAC/Xc in amps.

The concept of current THROUGH is fundamental and applies in all aspects of electronics apart from a very minor (and basically useless in electronics) discussion of what may happen on a physics level to single electrons inside a component.

Where does it end? Does current no longer go THROUGH a battery? What about a complex component that has capacitance and DC conduction? The human body where much of the current conduction is capacitive?

As far as making broad sweeping statements using the terms CURRENT and THROUGH we have to respect the necessary fundamentals. If the ammeter and circuit simulator and math calc all say current is "through" then it is. It is not necessary for any single electron to make it all the way around to have a series circuit with current through all the parts. It's not even necessary for electrons to move in the right direction, they are definitely subservient to the concept of current.

 

[MrAl]

Hello Mr RB,


Thanks for wording that out so near perfectly. That's the kind of discussion i like to see, as i am thinking everyone does. We should look at one other little thing too while we're at it which i'll get to in a minute here.

All i am saying here is that if an electron goes in one end (i also liked the way you narrowed it down to tracking one single electron) and comes out the other end, then that electron can not stay on the plate. That means charge can not accumulate and we dont get a buildup of the electric field between the plates. If charge builds up (as virtually everyone says it does) then it can not make it through at the same time. If an electron enters one side and stays on the plate, it can not leave the plate to exit out the other side. I think that is strange too but that' what everyone believes.

Also, that other thing we might think about is that in the AC circuit, i find it interesting that the current is maximum when the voltage is zero, and the voltage is maximum when the current is zero. That indicates that the capacitor is holding energy and releasing it later.

What might be happening is similar to the inductor where the charge enters one side and leaves the other, but for the capacitor that charge has to go through a conversion to some other form (field) before that energy can pass through. [Edit: actually the energy cant pass through either because then the capacitor would not be storing it! Duh on my part he he.]

But to state that a capacitor 'conducts' current (which is like saying the current flows through a capacitor) has to be wrong because what is happening inside there is much different than what happens inside a body like a resistor or even an inductor. For example, if i were to describe a lock (for ships) somewhere in the world, to state that water flows 'through' a lock would not be quite true because the water is first pumped in or out using an actual pump, and it doesnt flow through freely. The current in the capacitor doesnt seem to flow freely as at the very least it has to change energy form before it can move through, but once it changes form, it's no longer electrical current flow it would be considered a moving wave. Note a moving wave is not the same as charge flow. If you or i want to call a moving wave 'current', that's another story which would require rewriting what a 'current' is.

I am hoping that Professor Viken can help sort this out for us in some way. So far his ideas suggest pointing out the physical from the non physical. What is going through the capacitor is non physical as in a wave. That doesnt mean is has no physical significance, but a wave is just a wave until it is used for something, and that's not really the same as a current unless of course we are to rewrite theory as to what an electrical current really is. Still though, i would not be comfortable telling someone that current passes through a capacitor without specifying that "current has been redefined in the year 20xx so the wave is considered a current too" except of course in pure circuit theory where we dont care. That redefinition did not occur yet as far as i know of with this writing. In fact, even if it did get redefined in the year 2010 i still would not feel comfortable telling someone that current passes through a capacitor unless i spelled out the little history that went with it and how this new current actually gets through. Maxwell would not have had to call it 'displacement current' if it was just plain old 'current' right? In fact, the reason he called it displacement current (this is interesting) is because at the time there was another theory that was in vogue, and that was that there was an aether all around us. Maxwell called it 'displacement current' because he imagined that it displaced the aether! It has long been determined that there is no aether, so what he based that on was disproved.

I hope i've made this all clear but if you have any more comments please feel free to note them here even if you dont agree with something here.

 

[BrownOut]

The fact that displacement current was named after the msguided notion of ether is not what makes it a current. It has units of amps, a magnetic field and resolves current in a number of relations. Maxwell didn't base his belief this is current on the ether notion, he based the "displacement" discription on it. He based the current idea on the fact that Ampere's law needed another current term, and this term, in units of amps, fit the bill. Experimental evidence validates Maxwell. His breakthrough led him to discover radio waves. A pretend quantity or mistake could never had led to these important breakthrough. There is no need to re-define current to account for the current through the capacitor, Maxwell himself did that in 1861.

 

[MrAl]

Hello again,

Well you talk about a man who has been gone for many years. A lot has changed since then. Also, you know we are bringing this displacement current up for examination yet you insist on quoting things that can be taken BOTH ways (either side of the argument). If you want to prove that the displacement current is a true amperic current then you'll have to find a reference that actually states that, and if you quote an experiment it will have to somehow measure the current directly.
The problem is, anything you put between the plates to measure current, by definition, has to contain free electrons. Therefore you can not prove that there is a current between the plates, unless of course you can find another method which does not depend on the field.

If you want to quote Maxwell over and over that's up to you of course, but that's not the point of this thread. The whole point is, since the displacement current has been brought up into question (what it really is) and even Maxwell's interpretation was brought up into question (via MIT) we would like to figure out if this is real or not based on SOME OTHER evidence. Do you understand this concept now? We dont care what Maxwell said anymore anyway, but i think if you do want to quote him you should at least read up some more on the history of his time.
But whatever you find, we would like SOME OTHER evidence.

Thank you and have a good day.

 

[Mr RB]

What's wrong with the term displacement current? In the situation where you have 1 amp going through a cap, you can assume that 1amp worth of electrons are building up as an excess on plate A and 1 amp worth of electrons are being depleted from plate B. Doesn't that qualify as a "displacement" of electrons or a "displacement current" when applied to the cap as a whole?

I agree with Prof Viken regarding separating the physical from the non physical. In the physical sense you are concerned with what happens to a single electron and that single electron does not have to go "through".

In the non-physical (ie conceptual, practical, empirical) if you have 1 amp in and 1 amp out, so that clearly satisfies "1 amp through".

As regarding single electrons there's no way of knowing if that single electron goes all the way "through" a wire, or just goes in one end and a different electron comes out the other end. That's now entering the realm of statistics, given high enough current for long enough time it becomes probable that a single electron will go "through" the wire. Given a small enough current for a short enough time its high improbably that electron will get "through".

But in all cases we can respect that CURRENT goes "through".

 

[ljcox]

This thread is going around in circles.

I started this part of the discussion by raising "Displacement Current"

I thought I was making a simple point - that the world of Physics has not yet determined the "Theory of everything" and therefore the definition of current MAY change.

The simple concept of a current being charge carriers flowing in a conductor or in a beam (eg. in a CRT) has served us well for 200 years but it MAY need to be revised.

To extend my previously posted analogy of leaves floating on a stream, suppose that a father took a small child to a river & pointed to line of leaves floating past and he said "Look son, there is a current flowing in the river".

The boy would asume that the leaves were the current & that would be a logical assumption.

But we know that the real current is the unseen movement of the water and the moving leaves are a consequence.

So the "Theory of everything" MAY show there is something driving the charge carriers and hence eliminate the confusion between conduction & displacement current.

 

[MrAl]

Hello again,


Here i try to summarize the process of the transfer of charge and compare it to the so called displacement current by giving clear examples of how these processes really work in the real world. There should be absolutely no guesswork if you read this carefully and dont skip over any details. We may not have developed a TOE (yet ha ha) but at least we can explain the way some things work. In this way we can also bring this thread to a head.

I wish to first reply to the two previous posts and then i'll get on with it...

Mr RB:

The term "current" itself is the problem. "Displacement" isnt necessarily.
A "current" is something moves continuously while a "displacement" isnt quite the same. I'll explain more about how different these two things really are below after my other reply.

Yes, in the non physical sense if we have 1 amp in and 1 amp out that could be 'said' to constitute a 'current'.
But what about in the case where we have 1 amp in and 1 amp out and we dont actually have a 'current'? More about this below in full detail.
We can 'say' we have a current because it looks like we do in the leads of the capacitor. But just because it looks like an ordinary current that doesnt mean that it is. More below.

ljcox:

The thread is going around in circles, but we are talking about current flow and that goes around in circles too
You are right. We dont know everything but we can know the difference between conduction current and an interpretation of Maxwells "displacement current". The problem is knowing when we can apply either one, and apparently there is a difference of opinion when we can apply the displacement current and when we cant, other then in pure theory. In pure theory we can use Maxwells equation, but that's just an equation, an abstraction of reality, and even Maxwell did not like that, not at all. He sought to attach a visualization to every phenomena he tackled. One of these interpretations is known as the "displacement current".
We'll see how this is a displacement of charge and not a flow of charge.

Ok, done with the replies. Much thanks to those that replied.


If you followed this thread, you'll see that i was agreeing that something different was happening, other than the normal conduction current. You'll also see that i quoted an MIT professor that seems to deny that displacement current is real at all, and quoting again: "We now know that this is not the case". Note the use of the word 'now', as if something new has been discovered since the great Maxwell.

So what could possibly be going on here? One guy says this, one guy says that. But one thing has been common to all the arguments:
the displacement current is not named "conduction current", and conduction current is not named "displacement current". If the cap was simply conducting current Maxwell would not have had to add a new term to the equation. So we clearly have two different things happening here, but only happening when they truly apply to the case, and we must approach the these problems on a case by case basis. That's an integral part of being able to explain this phenomenon. Lose that, and pay the price with confusion.

The leaves in the water tells us that there is something there that is actually happening and something else there that is not only going along for the ride, it's masking the truth behind what is really happening physically. The difference is, in a circuits theory class you might be able to teach that "The leaves are moving and we can see that is true, so that's the answer to what is happening. The leaves move somehow because of their own power".
But in a physics class, you'd want to dig deeper and show that the water is what is really moving the leaves. That's like the water and lock example, where you can say that the boat flows through to make it simpler. In other words, the boat flows right through the lock and gets to the other side without any impediment. But that's not the way it really works. Again, in a circuits class you can say that the boat flows right through the lock, but in a physics class you would want to show how the lock actually operates. The idea is to dig as deep as you possibly can and see what you find, then try to describe it.

Now what we need is a good analogy that properly addresses the difference between conduction current and an interpretation of Maxwells displacement current. We know that these two things are different, in some way, however small, so we need at least two different examples to show how each one works, and that will reveal how they are truely different.
I also was pointing out that the application must be specified beforehand too, so that we may apply the correct example. For example, we would not apply the example of conduction current for the displacement current, and vice versa.

We also have to keep in mind that it is virtually impossible to show how something so fundamental to nature works by using items that are fundamentally made out of fundamental nature. This is a big problem, but we are nonetheless going to try very hard. In the end, we end up with an approximation at best, but it should give us much more intuition as to what is actually happening.

And with that good gentlemen, we now get to the examples of conduction current vs displacement current...


(Refer to attached diagram)

Case 1: The wire. Conduction current dominates and tiny tiny displacement current explained.
The wire conducts current by the process of continuous electron motion. One electron moves to the right, another moves in to take its place. The entire chain of electrons moves to the right continuously. But these electrons are not alone, they are part of the atoms that make up the wire. Those atoms also have other electrons, but there is not enough energy to move them out of their 'positions' so only the one or two electrons from each atom are free to move. These are sometimes called "free electrons", or "free charge". The other electrons are bound to the atoms, so they are called "bound electrons". Thus we have two kinds of electrons in a sense, the free ones and the bound ones. The bound ones can not move too far, but the free ones move and create the thing we call 'current'. We also note that the bound ones can move a small distance under the presence of a changing electric flux. It's interesting that if we could look at the end of the wire, we might detect an electron sticking out of the end, although still bound to it's atom. The other free electrons would be moving past that point, but that one bound one would be sticking out of the end at least partly.

Now we have 100 egg cartons lined up end to end and arranged in a circle so that the last egg carton meets the first at it's starting end. These egg cartons of course all have 12 pockets for eggs to rest inside of. Each of these 100 egg cartons has 12 eggs in two rows filling the entire set of cartons, except for the first one. That one has only 11 eggs in it. The other 99 cartons each have 11 eggs glued in place and one free to move in or out. The first one has all 11 eggs glued in place.
Oh yes, these cartons are very different than any you might buy at the store, as they are made of hard rubber. Also, the eggs are hard boiled (except for the ones with little chicks inside)
Now to start the current flow, we take the last egg out of the last carton and place it into the first carton.
This means that one egg was transferred ahead one carton so egg was therefore transported. This also created an empty pocket in the last carton, so we take an egg out of the second to last carton and place it into the last carton, but then the third to last carton is missing an egg, so we go to the one before that and take the egg from there and place it into the third to last carton, and we continue this process for all the cartons.
When we are done, we've managed to transport 99 eggs from one carton to the next, so each egg moved over by one carton. Note only the free ones could move however.
Something else happened too though because we found that we could get very good at this. We can move them so fast that the rubber carton holes start to warp, to bend in the direction of travel of the eggs. This happens to all the pockets where the stationary eggs are placed, but just a very very tiny amount. The rubber is very hard and only gives just a very small amount. We view this setup from the side so we can see the eggs moving and the rubber bending.
If we look at this very carefully, what this means is that we have transported more than 99 eggs. We've transported 99 full sized eggs, but what about the bent rubber holes? At the starting point we find that one of the eggs in the first carton has moved very slightly inward in the direction of travel, while in the last carton one egg has moved very slightly outward, thus we might say that we moved 99 eggs plus a tiny fraction of another egg. Thus, the bound eggs were very very slightly displaced as well as the free eggs having been moved. Thus we can say that here was conduction egg movement and tiny displacement egg movement. Note also that the displacement eggs moved must eventually return to their original position, while the conduction eggs dont have to.

Case 2: The dielectric. Displacement 'current' dominates and explained.
Above, we found that the free electrons move continuously through the wire, so it is easily conceivable that any electron can make it all the way around the closed loop circuit. But what about the bound electrons? It's pretty certain that since none of them can move very far none of them make it around the circuit. They stay right within the atom of the material that makes up the wire. But that does not mean that they can not move just a little. Read on.

Now instead of 100 egg cartons lined up end to end in a circle, we instead have 100 cartons made of rubber lined up end to end in a straight line, with 12 eggs in each carton, but all glued in place. That's 1200 eggs and that's a lot of eggs
We are going to view this not from the side, but from the open end of the first carton. Note our viewpoint has now changed, as we are looking straight at the end of the carton and we see all the other cartons in line. We have 100 cartons lined up end to end now so we have a whole wall of eggs, two eggs thick and 600 eggs wide.
Ok, so what we do now is we try to pull or push (to the right) one or more eggs out of EACH carton at the same time, but what happens is because they are glued in place we can not push or pull any of them out, but the force causes the rubber to bend to the right. Thus, at least some of the eggs in each carton lean to the right side, but not one of them moves out of its carton.
Now at first it may appear that we have not moved any eggs, but if we look closely at the right side of this structure of egg cartons (the front of the wall) we can see that there are possibly 600 eggs sticking part way out of the side of their cartons. Now if we have pushed 600 eggs only a small distance that amounts to one-sixth of their diameter, volume wise we have accomplished moving the equivalent of 100 eggs out of their cartons. Thus, although 100 eggs have not been actually moved out of their cartons, the equivalent of 100 eggs have been displaced. If we view this from outside of the egg cartons, it looks like 100 eggs moved out even though none actually did.

Case 3: The vacuum between two plates with moving charge. No conduction current, no real displacement current, field dominates.
The vacuum contains no charge whatsoever, but we have free charge to either side of the vacuum space and the moving electrons in the two plates will abruptly change direction and emit a virtual photon.
Now we have egg cartons with eggs, but they are lined up on either side of the vacuum. But in the vacuum we dont have any egg cartons, and we dont have any eggs. Instead, we have an empty space. We can do whatever we want to do, but with no eggs to move we can not cause a continuous egg flow, and with no cartons to bend we can certainly not displace any eggs. We basically cant do anything.In the egg cartons to the left and right of the space however that contain free eggs that are already moving, the free eggs might change direction abruptly and so an egg might 'crack' and the chick inside it could fly up and away from the egg. Thus, we would see chicks fly but we would never see any eggs move or displace.

Case 4? The end.
In the end it turns out that conduction current is a thin continuous STREAM of electrons, motivated to move by a close range imbalance of charge along a thin line, while displacement current,when it exists, is a WALL of electrons, motivated to move slightly by a long or short range imbalance of a wide field of charge which in turn causes a temporary apparent conduction movement in the wire and a temporary conduction in the wires of a dielectric capacitor.
In the vacuum capacitor, we have no current whatsoever, but only the field in which to store energy. The field comes from the change in direction of the electrons such that when the momentum of an electron changes it emits a photon. The photon, on encountering another electron, is free to again join with it to return the original energy to the plate. Thus there is no transfer of charge by any means, but merely an exchange of particles both during charge and during discharge.

Summary:
1. Conduction is a thin continuous lateral stream of electrons.
2. Displacement "current" is a tiny lateral movement of bound charge through an area, which can cause a conduction current in the wire. A better terminology choice would be "charge displacement" (not the same as charge separation).
3. In a vacuum (such as a vacuum capacitor), the exchange of particles is responsible for all the behavior and there is no conduction current nor displacement current within the vacuum itself.

 

[killivolt]

Very enjoyable read.

Thank you for your time and contributions. Mr.Al.

I like your examples easy to get into and out of the topic. Good Diagram.

Maybe it qualify's as a sticky or could be added to the theory section.

This would have been a good tool, back when I was trying to get capacitors.

Back then, I knew they packet a powerful punch if you were on the wrong side of it. I didn't get into the why of it all.

kv