Discharging a capacitor - how long does it take

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jsmith613 said:
just to check though, for a discharging capacitor, is the voltage across the resistor the same as that cross the capacitor BUT the for a charging capacitor the sum of the p.d's across the capacitor and resistor = source (i.e: they are not the same at all points)??

For the typical charging capacitor circuit, the sum of the resistor and capacitor p.d.'s is constant (equal to the voltage source).

Circuit schematic of a series RC circuit with a battery labelled E, a resistor labelled R and a capacitor labelled C, with a blue bracket on the right marked V_R + V_C = E.


Of course, for any complete "tour" around a given circuit the sum of all potential changes must be zero according to Kirchhoff.
 
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  • Circuit schematic of a series RC circuit: a battery labelled E on the left, with a resistor R and capacitor C in series on the right branch. A blue bracket on the right is labelled V_R + V_C = E.
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gneill said:
For the typical charging capacitor circuit, the sum of the resistor and capacitor p.d.'s is constant (equal to the voltage source).

Circuit schematic of a battery E in series with a resistor R and a capacitor C, with the blue label V_R + V_C = E across the two components.

yes...thanks :)

Of course, for any complete "tour" around a given circuit the sum of all potential changes must be zero according to Kirchhoff.

for this I just learn sum of p.d across componenets = emf of source (assuming wire have no resistance / no internal resistance)