Notice the prof also said that there was no way to distinguish the displacement current from the conduction current because they are both the same.
Well I think that says it all.
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Notice the prof also said that there was no way to distinguish the displacement current from the conduction current because they are both the same.
I believe I said that just because current can be measured on both sides of the capacitor was not proof that charge passes through the capacitor. If it did, the charge would not accumulate and it would not do what a capacitor does, store energy. Why didn't you discuss this earlier?
Now I'm going to get pedantic while you are busy backpedalling.
I said; "CURRENT flows though a cpacitor" and
You said; "No it doesn't"
I deliberately used the most simple example of where you were completely wrong about capacitor current rather than nitpicking the specifics of what happens inside a capacitor becasue frankly that doesn't matter.
1. you have 3 mystery comonents in series,
2. your instrument is one ammeter at the end of the series which registers 1 amp, a single reading at one point in time
3. deduce which one of the 3 components is the cap because "there is no current flowing through it"
If you think that a capacitor dosn't store energy when an AC voltage is applied, just try disconnecting a capacitor from a mains source when the AC waveform is at its peak, then put your fingers across the terminals.!!
Or the other test you could do is to connect one end of a 2uF capacitor to the Line of the mains supply and touch the other end of the capacitor with your finger..
He more or less said the the current through the dielectric was a virtual or pretend current.
1: being such in essence or effect though not formally recognized or admitted
That tells me that he is saying that it's not a current but the effect makes it look like a current.
If I turn on my radio, I hear the results of displacement current.
If I trun on a light, I see the results of displacement current.
Until someone proves I can get real results from an unreal quantity, then I must conclude displacement current is real.
Well, if i throw a baseball at a painted steel stop sign and it hits it on the right side so it twists a little, then generate a magnetic field to make the stop sign rotate, both things caused the sign to rotate (a little) but they are not the same cause. For that matter, if i throw a basketball at the same sign, same thing happens, yet a basketball is not the same as a baseball.
Another way of looking at it would be something like this....
so can we really 'cherry pick' to show that he actually is saying that the displacement current is the same as any other current? If you can show this then i guess we would have to dismiss that lecture.
I know what you're trying to say, but you anology falls flat, as you're talking about apples and oranges. We aren't talking about different well known forces that move objects, we're talking about creating a magnetic field, and only a current can do that. Come back and see me when you can throw a baseball and create a magnetic field. Placing static charge on the leather doesn't count
Or, one might say that someone who believs in the complex world believes current can happen without charge, and is not discouraged by the duality of certain phenomina.
Yes, we definitely can ( cherry pick to show dispalcement current is real ), but now you're saying you have to dismiss the lecture when it opposes your preconceived notion, while you are willing to embrace it when it supported the same. Sorry, I don't think like you.
Maybe i didnt make the point clear about dismissing the lecture. I meant that if someone says that the displacement current isnt real and then says it is real isnt that a contradiction unless they are still within the process of discovery?
Still, i need a direct quote if you are going to argue that point, if you dont mind i'd like to see where he says this. Which lecture was it in? I'll watch it. I don't think he ever said displacement current isn't real. That was someone's liberal interpretation of what he said.
Im not talking about fruit (this time ) im talking about two things looking like the same thing when really they are two different things. We can say Electromagnetic Theory as one thing, or we can say Magnetic Theory alone, but that doesnt mean that Electrostatics are the same 'exactly' as Magnetics. It's a very simple concept. There is continuity between electrostatics, magnetic and electromagnetic theory. They cannot be discussed as though they are 3 distinct things. I know you're trying to say "something" else can produce a magnetic field, but I disagree. Magnetic fields are literally defined by current. Until someone finds that elusive "something else", it can only be current.
I will admit though that i might be wrong about the B field in a poor conductor because the voltage does not only depend on the insulator properties, it depends on the properties of the circuit too. This deserves more thought though that's all i'll say for now about that.
**broken link removed** Originally Posted by MrAl **broken link removed**
Hello again,
Ok i'll keep this short so you dont have to read a book just to read what my point is about...
This is a DIRECT quote, unmodified in any way from the lecture. This is not a rewording or reinterpretation...
"The changing E field will create a B field and according to the right hand rule, this will act like current, even though it is not current."
This is from the lecture: "Displacement current example 2".
What does "even though it is not current" mean to you?
Later in his lecture, he says, "We can see now that in addition to regular current, we have displacement current flowing through the capacitor..." So, there is "regular" current and "displacement" current. Taken out of context, and taken far too literally, his comment about not "being current" might suggest something else. But considering context and remembering he was speaking extemporaneously, and thus needs to be interpreted with intelligence and not dogma, he was most likely referring to "regular" current or moving charge. I believe he clears that up later in the lecture.
Well then perhaps we need a better experiment because everything i heard in that lecture says that the displacement current is not the same thing as real current.
So here we have the *current* at zero yet we still have what is called the *displacement current*.
Obviously displacement current has to be something else here because we cant say that the current is zero AND the current is not zero.
"We can see now that in addition to regular current, we have displacement current flowing through the capacitor..."