General > General Technical Chat
Veritasium "How Electricity Actually Works"
PlainName:
--- Quote ---How come that after capacitor is charged no more current is flowing ?
--- End quote ---
The cap is fully charged so cannot be charged more.
--- Quote ---The answer should be obvious and that is energy went in to capacitor not trough.
--- End quote ---
The CHARGE went into the capacitor. The energy went around the circuit to allow charging. Once the capacitor is charged there can be no more circulating power, so no more energy. But if there is charge going INTO the capacitor then there is power going AROUND the circuit. If that wasn't so you wouldn't NEED a circuit!
snarkysparky:
What difference does it make if the resistors are part of the return circuit of the capacitor. Nobody would argue that.
What we know is that being in that return circuit for the "Capacitor" they get to absorb some of the charging energy.
This charging energy is a result of electrons going into one terminal of the capacitor and out the other.
So we have electrons entering and leaving the terminals of the capacitor that go on to impart some energy in other things in the "return path"
And if we keep switching the polarity of the input we can keep getting power out in the return path.
This power will not flow without a route into and out of the capacitor terminals. the capacitor in integral to the transfer of power to the load. All this is very simple.
electrodacus:
--- Quote from: dunkemhigh on May 21, 2022, 09:14:48 pm ---The cap is fully charged so cannot be charged more.
The CHARGE went into the capacitor. The energy went around the circuit to allow charging. Once the capacitor is charged there can be no more circulating power, so no more energy. But if there is charge going INTO the capacitor then there is power going AROUND the circuit. If that wasn't so you wouldn't NEED a circuit!
--- End quote ---
Yes capacitor is charged and can not charge more.
Energy and more specifically electrical energy went into capacitor not around it. If it will have been going around it then less energy will have been needed from the supply.
144mJ worth of energy left the supply.
72mJ where dissipated as heat in the wires
72mJ where stored in the capacitor.
For a capacitor:
Charge is C * V
Energy is C * V * V * 0.5
Can you understand the relation and also the difference ?
electrodacus:
--- Quote from: snarkysparky on May 21, 2022, 09:24:50 pm ---This charging energy is a result of electrons going into one terminal of the capacitor and out the other.
So we have electrons entering and leaving the terminals of the capacitor that go on to impart some energy in other things in the "return path"
And if we keep switching the polarity of the input we can keep getting power out in the return path.
This power will not flow without a route into and out of the capacitor terminals. the capacitor in integral to the transfer of power to the load. All this is very simple.
--- End quote ---
The electrons going in to one plate will never get on the other side. Those electrons that exit the other side where already there in that plate.
This excess of electrons on one plate and deficit on the other plate is the stored energy.
After 144mJ left the source and you get to steady state. You remove the terminal from the supply and connect them with reverse polarity.
What will happen then ? How much energy will be dissipated on the 1Ohm wires ?
Initially it was 72mJ but how much will it be when you change the polarity ?
PlainName:
--- Quote ---Can you understand the relation and also the difference ?
--- End quote ---
Can you not understand that to charge the capacitor you need a completed circuit for SOMETHING to go around. If you leave off the return path then nothing will happen. Therefore something must be going down that return path.
Are you saying that this is wrong? That you don't need a completed circuit for the capacitor to charge?
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