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| Veritasium "How Electricity Actually Works" |
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| TimFox:
--- Quote from: Naej on May 23, 2022, 06:46:19 pm --- --- Quote from: HuronKing on May 23, 2022, 05:34:38 pm ---The 'energy always travels in wires' people cannot hope to design, let alone explain, how a high-frequency waveguide works and how to CONTROL where energy is going. --- End quote --- It's in the conductor, and follows the conductor. And if you put holes, you'll start radiating the energy. Can the 'energy always travels in vacuum' people explain why you need conductors in waveguides? (in dielectrics, you have polarization current instead of current) Or, since waveguides are wires, in circuits? --- End quote --- There are dielectric waveguides for microwave frequencies, usually using a high-dielectric-constant ceramic for the walls. https://farside.ph.utexas.edu/teaching/jk1/Electromagnetism/node118.html |
| electrodacus:
--- Quote from: IanB on May 23, 2022, 06:54:28 pm ---I think one simple (or simplified) way to look at things is that delivered power is the product of voltage and current. The voltage comes from the E field. A strong E field can be propagated by wires and can give a large power delivery, but it has to travel the length of the wires to arrive. A weaker E field can be propagated across the air gap and can give a much smaller power delivery, but it can arrive faster. This qualitatively aligns with Derek's experiment. --- End quote --- You only have an E field when you have a delta in charge. So you need first the extra electron then you have the E field. There is a very strong E field between the plates of a charged capacitor so how come that no energy is transferred from one plate to the other basically discharging the capacitor? What you consider that weeker electric field it is due to delta in charge between the two wires. Those parallel wires form a capacitor that is an energy storage device and energy from battery flows in that capacitor (in and not trough) and since energy travels through wires from battery to that capacitor and the lamp or resistor is also a wire the energy to charge the capacitor will flow through them. If energy will not have traveled through wire then wire thickness will not have matter. You could transfer a lot of power from battery to lamp/load with a very thin copper wire that just shows the power the direction it needs to travel :) It is like saying that energy from a compressed air tank is delivered to a compressed air tool outside the hose. |
| IanB:
--- Quote from: electrodacus on May 23, 2022, 07:23:11 pm ---Those parallel wires form a capacitor that is an energy storage device and energy from battery flows in that capacitor (in and not trough) and since energy travels through wires from battery to that capacitor and the lamp or resistor is also a wire the energy to charge the capacitor will flow through them. --- End quote --- I see. So if you have three capacitors in series, the energy to charge the middle capacitor flows through the outer capacitors. If energy does not flow through the outer capacitors the middle capacitor will not be charged. If energy does flow through the outer capacitors the middle capacitor will be charged. |
| electrodacus:
--- Quote from: IanB on May 23, 2022, 07:50:51 pm ---I see. So if you have three capacitors in series, the energy to charge the middle capacitor flows through the outer capacitors. If energy does not flow through the outer capacitors the middle capacitor will not be charged. If energy does flow through the outer capacitors the middle capacitor will be charged. --- End quote --- At no point in time any energy flows through the capacitor. 3 or more capacitors in series are no different from a single capacitor. If all 3 capacitors are 1000uF when connected in series will look like only a single 333uF capacitor. Imagine a parallel plate capacitor with 5mm between plates and say it has 1uF capacitance. Then insert a very thin 0.001mm plate between the two plates with same area. This will be the equivalent of two capacitors in series so from outside the capacitor will still look like a single 1uF capacitor (just slightly more due to that 0.001mm reduction in distance between plates). If that plate is instead 2.5mm thick then from outside it will look like a 2uF capacitor but it is actually two 4uF capacitors in series. Adding multiple plates will not change the fact that from outside any number of series connected capacitors will appear as a single capacitor and it can be charged. There will be a current flow inside the middle plate as electrons from one side of the plate travel to the other side (it is a short distance even for the 2.5mm thick plate) but there is still a current flow as electrons that where already there travel from one side of the plate to the other while capacitor is being charged. This charge separation remains there after you remove the battery so it is stored energy not used energy. Now this capacitor or series capacitors can be used to do any sort of work you want with that stored energy. |
| hamster_nz:
--- Quote from: electrodacus on May 23, 2022, 07:23:11 pm ---If energy will not have traveled through wire then wire thickness will not have matter. You could transfer a lot of power from battery to lamp/load with a very thin copper wire that just shows the power the direction it needs to travel :) It is like saying that energy from a compressed air tank is delivered to a compressed air tool outside the hose. --- End quote --- Run your "compressed air" analogy, with a hard vacuum in the pipe instead, supplied from a very large cylinder, with a very good vacuum pump. The pipes are literally delivering nothing, so energy can be extracted from the air around the pipes. If your pipe is too tiny, you won't get enough 'nothing' to run your tools efficiently, but it won't matter if the pipe is too large. Pipes are essential to the system working, even though they carry no usable energy. The energy is outside of the pipes, but the pipes dictate where you can extract the energy - no pipe, you can't do work. |
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