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# Voltage across capacitor :S watch

1. My ubderstanding of the volt is that it is the numerical value for the joules of energy transfered per unit charge. So the voltage of 1v across an electrical component means that a joule of energy is transferred by a coulomb of charge as it flows through it so how what does 'voltage across a capacitor' mean since in the presence of a capacitor there is now flow of charge... Noob at phy, just started in the beginning of december.
2. (Original post by nonipaify)
My ubderstanding of the volt is that it is the numerical value for the joules of energy transfered per unit charge. So the voltage of 1v across an electrical component means that a joule of energy is transferred by a coulomb of charge as it flows through it so how what does 'voltage across a capacitor' mean since in the presence of a capacitor there is now flow of charge... Noob at phy, just started in the beginning of december.
The capacitor plates contain an imbalance of charge which creates an electric field in the dielectric between the plates.

The electric field makes it increasingly difficult for more like charges to enter the plate area and this ripples back to the supply via the electrons in the conductors.

Eventually, the e.m.f. provided by the supply will be in equilibrium with the electric field between the capacitor plates.

So, that 1V across the capacitor, relates to the energy stored in the electric field as 1 joule per coulomb of static charge.

When current flows in or out of the capacitor, the electric field must also change and hence the voltage developed across the capacitor also must change in accordance with the relationship:

V = Q/C
3. (Original post by nonipaify)
My ubderstanding of the volt is that it is the numerical value for the joules of energy transfered per unit charge. So the voltage of 1v across an electrical component means that a joule of energy is transferred by a coulomb of charge as it flows through it so how what does 'voltage across a capacitor' mean since in the presence of a capacitor there is now flow of charge... Noob at phy, just started in the beginning of december.
Doesn't need to be a current flowing, it's just the energy on a coulomb of charge full stop.

frequent analogy is gravitational potential energy with voltage being height and charge being mass.

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