General > General Technical Chat
"Veritasium" (YT) - "The Big Misconception About Electricity" ?
bdunham7:
--- Quote from: adx on January 13, 2022, 10:21:16 pm ---Ok, how about assuming the field isn't real. It is always the interaction between charged particles.
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That's essentially QFT and possibly a bit closer to "what is really going on", especially if you generalize that to eliminate 'charged'. Which is why I kept croaking that you can't consider power to be 'in' the fields on their own without considering charges.
EEVblog:
--- Quote from: adx on January 13, 2022, 03:39:40 pm ---
--- Quote from: EEVblog on January 13, 2022, 06:41:14 am ---I've been gone for several weeks, can someone TLDR me what happened here in regards to the quantum field theory explanation? Thanks.
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Not sure, but I think it's done at least one more cycle of spiralling in on zero or more answers!
Best I can see is it's down to semantic differences, which trigger different thought pathways in people's heads leading them to have no way to reasonably dispute what they are now thinking, or at least wondering about the conflict now centred in their minds rather than projected externally. I say, faux psychoanalytically.
I'm starting to wonder if classical theory is grossly misleading through no fault of its own, just that it has propagated through textbooks where the authors have struggled for teachable meaning, now just layers of history and interpretation. Should have prefaced that with an extreme cynicism warning, but seems too true.
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I like QTF in that it seems to predict that in all probability the majority of energy flow is inside the wire. This just makes sense to me at DC.
So my mind keeps going back to DC and say an example of a 50mm diameter HVDC undersea cable. You can't tell me there is no energy flowing inside the copper cable at DC? ZERO! That just seems nuts.
Extend it to 1m diameter if you want. All the energy is still outside the cable at DC? Really?
Usually it's the quantum world that doesn't make intuitive sense, but in this case QTF seems to make intuitive sense at DC.
rfeecs:
--- Quote from: EEVblog on January 13, 2022, 11:04:03 pm ---I like QTF in that it seems to predict that in all probability the majority of energy flow is inside the wire.
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But does QFT predict that?
Shouldn't QFT give the same results as the classical model? The classical model agrees with measurements. By the correspondence principle (https://en.wikipedia.org/wiki/Correspondence_principle), QFT should do the same.
Of course, if we can't actually measure "energy flow", then that could be a problem. In that case, QFT's prediction would be just as useless as the classical model.
EEVblog:
--- Quote from: rfeecs on January 13, 2022, 11:24:28 pm ---
--- Quote from: EEVblog on January 13, 2022, 11:04:03 pm ---I like QTF in that it seems to predict that in all probability the majority of energy flow is inside the wire.
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But does QFT predict that?
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That's what the quantum professor says in her video. She says QFT essentially trumps Poynting theorm in understanding, which doesn't make Poynting obsolete.
it's just that if you want to understand whether or not the energy actually flows within the wire or outside the wire, QFT appears to say it's almost entirely inside the wire. I'm sure the maths still works either way, it's about understanding and answering the inside/outside question posed by Derek. He did not consider QTF at all and only looked to Poynting for the answer.
I did try to research some articles on it before I went on holidays but my head exploded.
bdunham7:
--- Quote from: rfeecs on January 13, 2022, 11:24:28 pm ---Shouldn't QFT give the same results as the classical model? The classical model agrees with measurements.
Of course, if we can't actually measure "energy flow", then that could be a problem. In that case, QFT's prediction would be just as useless as the classical model.
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You've neatly summarized the issue. Both the QFT and classical model will agree as to the movement of the charges, the dissipation of energy in the load, the surface charges and fields, the magnetic fields and so on. So both should agree with any actual physical measurements you can take, but they arrive at their results differently. There's no reason to assume that the two models have to agree on intermediate constructs like probability, virtual particles, S-fields or other mathematical results.
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