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Better understanding of capacitor charging

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Akanimo said:
The voltage will not drop. Instead, it will go up.

When you decrease the distance between the plates, the field becomes stronger. This means that the capacitance decreases because you now need less energy to keep the charges on the plates as there's already a stronger attraction between the unlike charges on the two plates.
This also implies that the voltage increases since the charges are still intact. This could be easily seen with this known formula:

Q=CV

Since Q is constant, if C decreases, V must increase proportionately. A lower capacitance requires a lesser amount of charge to increase the voltage by 1V. Remember?
Click to expand...

Sorry about that. I wrote it the opposite way. Thanks FvM for pointing that out.

Correction:
The voltage will drop as depicted by formula:

Epsilon*A/d

When you decrease the distance between the plates, the field becomes stronger. This means that the capacitance increases because you now need less energy to keep the charges on the plates as there's already a stronger attraction between the unlike charges on the two plates.
This also implies that the voltage increases since the charges are still intact. This could be easily seen with this known formula:

Q=CV

Since Q is constant, if C decreases, V must increase proportionately. A lower capacitance requires a higher amount of charge to increase the voltage by 1V. Remember?
 
Last edited:
Akanimo said:
Sorry about that. I wrote it the opposite way. Thanks FvM for pointing that out.

Correction:
The voltage will drop as depicted by formula:

Epsilon*A/d

When you decrease the distance between the plates, the field becomes stronger. This means that the capacitance increases because you now need less energy to keep the charges on the plates as there's already a stronger attraction between the unlike charges on the two plates.
This also implies that the voltage increases since the charges are still intact. This could be easily seen with this known formula:

Q=CV

Since Q is constant, if C decreases, V must increase proportionately. A lower capacitance requires a higher amount of charge to increase the voltage by 1V. Remember?
Click to expand...

Correction:
The voltage will drop.

When you decrease the distance between the plates, the field becomes stronger. This means that the capacitance increases, as depicted by formula C=Epsilon*A/d, because you now need less energy to keep the charges on the plates as there's already a stronger attraction between the unlike charges on the two plates.
This also implies that the voltage increases since the charges are still intact. This could be easily seen with this known formula:

Q=CV

Since Q is constant, if C decreases, V must increase proportionately. A lower capacitance would have a higher voltage for the same amount of charge difference between the two plates . Remember?
 
Last edited:

Akanimo said:
The voltage will not drop. Instead, it will go up.

When you decrease the distance between the plates, the field becomes stronger. This means that the capacitance decreases because you now need less energy to keep the charges on the plates as there's already a stronger attraction between the unlike charges on the two plates.
This also implies that the voltage increases since the charges are still intact. This could be easily seen with this known formula:

Q=CV

Since Q is constant, if C decreases, V must increase proportionately. A lower capacitance requires a lesser amount of charge to increase the voltage by 1V. Remember?
Click to expand...

As you can see from this link http://hyperphysics.phy-astr.gsu.edu/hbase/electric/pplate.html , the closer the plates, the higher the capacitance and the lower the voltage. The electrostatic field is stronger when the plates are closer, but it it also shorter.

Ratch

- - - Updated - - -

c_mitra said:
SI base units are clearly explained in this page: http://physics.nist.gov/cuu/Units/units.html

Some of the derived units are also there.
Click to expand...

Then you agree that voltage and temperature are energy densities?

Ratch
 
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