General > General Technical Chat
Veritasium "How Electricity Actually Works"
T3sl4co1l:
Capacitors: about 20nF each.
Wire: I could measure it, but actually, you have enough information now to calculate this.
The system is isolated on battery power. Anyway, it's only powered before the switch turns on.
Will my setup produce the fabled 0.71 Vi you have predicted?
Tim
electrodacus:
--- Quote from: T3sl4co1l on May 04, 2022, 01:59:21 am ---Capacitors: about 20nF each.
Wire: I could measure it, but actually, you have enough information now to calculate this.
The system is isolated on battery power. Anyway, it's only powered before the switch turns on.
Will my setup produce the fabled 0.71 Vi you have predicted?
Tim
--- End quote ---
20nF ??? so you have build some LC oscillator.
I was for good reason using 1F as an example but at least hundreds or thousands of uF will be useful for such a test.
Someone else here had a video with a test using some larger Electrolytic capacitors. I was expecting you use some similar setup and maybe you had some strange isolation problem due to non isolated switch driver. But matched inductance and capacitance also make sense and that is most likely you case as 20nF is basically nothing.
If you use large capacitors Large electrolytic or super-capacitors then you can use a DC-DC converter with constant current control and get very close to 0.7 Vi
The probing was also strange as I have no idea why you will connect the oscilloscope ground to the switch. But is fairly clear that you have build an LC resonator so not at all what is shown in that diagram two parallel capacitors and a switch.
T3sl4co1l:
--- Quote from: electrodacus on May 04, 2022, 02:10:36 am ---20nF ??? so you have build some LC oscillator.
I was for good reason using 1F as an example but at least hundreds or thousands of uF will be useful for such a test.
--- End quote ---
Sure, but I don't have superconducting capacitors that large. Are you saying this effect disappears for small values, then? By what mechanism? That's quite a peculiar effect if so!
--- Quote ---Someone else here had a video with a test using some larger Electrolytic capacitors. I was expecting you use some similar setup and maybe you had some strange isolation problem due to non isolated switch driver. But matched inductance and capacitance also make sense and that is most likely you case as 20nF is basically nothing.
If you use large capacitors Large electrolytic or super-capacitors then you can use a DC-DC converter with constant current control and get very close to 0.7 Vi
The probing was also strange as I have no idea why you will connect the oscilloscope ground to the switch. But is fairly clear that you have build an LC resonator so not at all what is shown in that diagram two parallel capacitors and a switch.
--- End quote ---
But I was told a DC-DC converter is not required, this effect will be observed for superconducting wires?
I have wired the diagram exactly as shown, I'm not sure what is missing?
Tim
electrodacus:
--- Quote from: T3sl4co1l on May 04, 2022, 02:28:45 am ---
Sure, but I don't have superconducting capacitors that large. Are you saying this effect disappears for small values, then? By what mechanism? That's quite a peculiar effect if so!
--- End quote ---
Are you saying those 20nF capacitors are made of superconductor material ? Even the wires ?
Do you also have the means to cool them down to whatever temperature is needed to become superconductors ? You will not be able to use a mosfet switch in that case anyway.
--- Quote from: T3sl4co1l on May 04, 2022, 02:28:45 am ---
But I was told a DC-DC converter is not required, this effect will be observed for superconducting wires?
I have wired the diagram exactly as shown, I'm not sure what is missing?
Tim
--- End quote ---
The effect can be observed for superconducting wires (this need to include the switch and the capacitor plates). Unless you have access to some university lab with this sort of equipment I doubt this is an option for you.
You did not wired as shown in diagram as you added significant inductance connecting the super small 20nF capacitors with wires. There is no inductor drawn in the schematic for a good reason.
And yes you can not get rid of inductance or capacitance but when the diagram shows capacitors only you understand that inductance in that circuit will need to be negligibly small and that is not possible when you connect 20nF capacitors with wires.
So use some few mF electrolytic capacitors and low power and efficient DC-DC converter as it is way easier and less expensive to setup than superconductors.
I also want to insist on the fact that I already proved multiple times with the correct equations that what I say is correct.
Main equation is the one for Energy stored in a capacitor = 0.5 * C * V2
initial condition 3V charged capacitor identical 1F capacitors
0.5 * 1 * 32 = 4.5Ws
end result after switch is closed and steady state is reached ideal case or very close with efficient DC-DC
0.5 * 2 * 2.1212 = 4.5Ws
end result with resistance in series
0.5 * 2 * 1.52 = 2.25Ws with the other half of the energy lost as heat due to circuit resistance.
hamster_nz:
--- Quote from: electrodacus on May 04, 2022, 03:06:53 am ---So use some few mF electrolytic capacitors and low power and efficient DC-DC converter as it is way easier and less expensive to setup than superconductors.
--- End quote ---
It is also 'cheating'. I too could get any answer I want if I am free to add to the system. If I said "let me put an inductor in there, a diode, a switch and a trained imp that can push the switch really quickly" would you not agree that that is not the same problem any more?
You are now worrying about wires (even superconducting ones) having inductance. Why worry? A moving charge induces a magnetic field. That is how the underlying physical reality works - a wire with zero self-inductance cannot exist! (well, is infinitely short... so no longer a wire)
Do you agree that charges moving between the capacitors will induce changes in the magnetic field? If so, there is the source of the L for the LC resonator - it's not a flawed component, it is built into nature.
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