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| Veritasium "How Electricity Actually Works" |
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| electrodacus:
--- Quote from: T3sl4co1l on May 09, 2022, 07:59:37 am ---So current is going into, but it's not? And it's going through, but it's not? And energy is going into, but it's also not? It seems you can't produce a coherent description of any of the particulars in these matters, in addition to use of the above words... at least not in terms that anyone else can make any meaning of. If it's so frustrating and annoying, then... why bother? You know the phrase, "better to be thought a fool..."? Tim --- End quote --- You have a 3V supply and at some particular point in time 1.5V drop across the capacitor and 1.5V drop across the resistor and say the current is 1A Then you have 1.5V * 1 A = 1.5W going in to capacitor (being stored) with no resulting heat so no work done and you have same 1.5W on the resistor all ending up as heat so not stored. So from the supplied 3W only 1.5W across the resistor is doing work so energy is being used and 1.5W is stored no work is done with that. Similarly say power supply is set to output constant current 1A and you connect that to a capacitor any value and while there is current flow there is no work done as current flows in to capacitor and is being stored Then second case you have a 1.5Ohm resistor connected to the same constant current 1A output power supply and all this 1.5W will go through resistor resulting in to heat so work is done. If you understand the above example let me know how you explain in a better way energy flowing in/out of capacitor vs energy flowing through a resistor as there is a big difference between the two. |
| electrodacus:
--- Quote from: SandyCox on May 09, 2022, 09:06:49 am ---Yes. This will work. Make a four-layer capacitor with foil and paper. Charge the outer two layers. You will then be able to extract energy from the capacitor formed by the inner two layers. --- End quote --- That is exactly like having 3 capacitors in series that you charge and then remove the middle one. It only proves what I'm saying. If you push 3Ws worth of energy "in to" those 3 series capacitors (distance equal between plates so they have equal capacity) then each of them will contain 1Ws and none of the energy did any work it was just stored so no 3Ws worth of heat or visible photos or anything like that just stored for later use. If my definition of going in/out or trough seems unclear let me know how will you word the difference between doing work or just storing energy ? |
| Naej:
--- Quote from: bsfeechannel on May 09, 2022, 02:25:04 am --- --- Quote ---You don't call wires, capacitors, coils and antennae "Maxwell stuff" do you? --- End quote --- Why not? Will they get offended? --- End quote --- Clearly you're not doing this so why don't you answer your own question? --- Quote from: bsfeechannel on May 09, 2022, 02:25:04 am --- --- Quote ---Well you say energy flows through vacuum just to mock engineers, why can't I say it flows through wires? --- End quote --- You don't get it. I AM an engineer. If you want to contradict the experimental data, knock yourself out. --- End quote --- I don't, I'm just saying energy flows through wires, which contradicts no experimental data whatsoever. If there were experimental data supporting the energy part of the slogan "Wires transfer charge. Space transfers energy." we would have known about them and they would be in books. ::) |
| HuronKing:
--- Quote from: Naej on May 09, 2022, 04:19:50 pm ---I don't, I'm just saying energy flows through wires, which contradicts no experimental data whatsoever. If there were experimental data supporting the energy part of the slogan "Wires transfer charge. Space transfers energy." we would have known about them and they would be in books. ::) --- End quote --- You've not read Hayt then? --- Quote ---The question of where the energy is stored in an electric field has not yet been answered. Potential energy can never be pinned down precisely in terms of physical location. Someone lifts a pencil, and the pencil acquires potential energy. Is the energy stored in the molecules of the pencil, in the gravitational field between the pencil and the earth, or in some obscure place? Is the energy in a capacitor stored in the charges themselves, in the field, or where? No one can offer any proof for his or her own private opinion, and the matter of deciding may be left to the philosophers. Electromagnetic field theory makes it easy to believe that the energy of an electric field or a charge distribution is stored in the field itself... --- End quote --- Engineering Electromagnetics p.106 (8th Edition) He goes on to make an argument for why the field interpretation is preferred. And when he gets to waveguides, there is no question what Hayt thinks: --- Quote ---Stated more generally, all fields in a good conductor such as copper are essentially zero at distances greater than a few skin depths from the surface. Any current density or electric field intensity established at the surface of a good conductor decays rapidly as we progress into the conductor. Electromagnetic energy is not transmitted in the interior of a conductor; it travels in the region surrounding the conductor, while the conductor merely guides the waves. We will consider guided propagation in more detail in Chapter 13. --- End quote --- Engineering Electromagnetics p.407 (8th Edition) I'm fine with folks digging in to "charges store and transfer energy" (even if I think their interpretation is clunky and inelegant for explaining how energy can cross an air gap so this is not what I teach in my motor laboratories) but let's not pretend there aren't reputable textbooks that firmly take the 'energy is in the fields' interpretation of Maxwell and the experiments done on electromagnetic radiation. |
| electrodacus:
One of you mentioned a Wimshurst machine (converts mechanical energy in to electrical energy) and I found a video correctly explains how it works so if you are able to understand his high quality video and more importantly correct explanation then you will understand why energy travels through wires. There are a few places on that machine where energy travels outside metal conductors but energy is still carried by electrons and not fields as electrons travel through a small space between wires. Hes animation shows that effect very nicely. I think that is a fantastic video and unless you do not agree that is what happens there it debunks Derek's claim that energy travels outside the wire in his experiment. |
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