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"Veritasium" (YT) - "The Big Misconception About Electricity" ?
Naej:
--- Quote from: Sredni on January 25, 2022, 11:38:48 am ---To my knowledge, the AB effect is a quantum effect that manifest itself on a microscopic scale (as bsfeechannel pointed out a few posts back). Very loosely speaking, it can be thought as being the consequence of the 'smearedness' of the wave function of the electrons: even if the little hard sphere we represent in our mind as being an electron is in a region without B, its wave function is spread out to encompass the microscopic solenoid and the region where B is.
It happens to be as magic as the interference of an electron with itself in the the double slit experiment. If we think the electron as a little hard sphere, then the double slit experiment with single electrons can only be explained by black magic. It appears that the little ball is capable of 'sensing' the presence of the slit it does not go through. But when you consider wave functions, that are delocalized, it seems a little less strange (while still remaining strange, but that is because we are limited to think in terms of either waves or particles).
The AB effect, an electron being able to sense the static magnetic field 'hidden' inside the solenoid, can thus be compared to the ability of an electron to sense the slit it did not pass through.
Trying to transpose this behavior to the macroscopic world is, in my view, trying to say that John, who entered the room through the front door, has also entered the room through the window. Or that, since in the quantum realm there is a tunnel effect, there is an appreciable probability that John has walked through walls. No, that probability is appreciable only if John is the size of an atomic particle and the walls are nanowide.
(A final note: in the case of the toroid in the macro world, we are able to 'detect' the B field hidden inside the infinite solenoid because it is changing and therefore the dA/dt brings into existence an actual electric field Eind in the point P outside the solenoid. Locality is saved. The AB effect is about a constant B field, so dA/dt is zero and there only is a time-constant A around the solenoid)
--- End quote ---
Absolutely not. Even if the solenoid is inside an impenetrable barrier (the electron wavefunction is 0 in this position) , you still get the effect.
What it shows is that the potential momentum A is actually a thing: the electron detects a changing A along its 'path'.
rfeecs:
A couple more videos from Ben Watson:
Naej:
Maybe there's a simple word for a build-up of surface charges on two opposing conductors separated by a dielectric?
SiliconWizard:
Fields galore =)
aetherist:
--- Quote from: Howardlong on December 08, 2021, 09:34:38 pm ---I re-did the ladder line tests I ran a few days ago to demonstrate the ~80ps delay over the 24mm wire spacing.
I used the same probe to probe the "switch" (the scope's integrated TDR, cyan reference trace) and the bulb side (green trace) so as not to introduce skew.
The cyan trace was taken at 10mV/div and the green at 2mV/div, so there's significant attenuation before we approach DC steady state.
The yellow trace is the TDR trace which you can't get rid of without turning off the TDR: the TDR triggers the scope and turns on a long time before the displayed traces, it has to propagate through the cables to the DUT, note the trace delay of ~27ns.
I measured the time between the beginning of the two rising edges, at about the 10% level.
(The scope's pretty dusty: I had a ceiling collapse some months ago in the room adjacent to this, and it's still being repaired, so things get pretty dusty round these parts.)
--- End quote ---
Nice. I have not seen any comments re your experiment.
I did not know that old scopes had 20 GHz -- how much did they cost new? -- how much nowadays secondhand?
It confirms that some kind of crosstalk (mainly radio i suppose) crosses (the 24 mm) at c m/s.
I would like to analyse your results, could u please advise....
1. The rise time of the pulse?
2. The fall time of the pulse?
3. The overall time of the pulse -- or the flat time (ie total time minus the rise & fall)?
4. Or was it a step pulse, ie with no fall?
Thanx.
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