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Transient Current

Suppose a 6 volt battery, a 10 ohm resistor, a 15 uf capacitor, and a switch are hooked up in series while the switch is open. The switch is closed at the same instant that a stopwatch is started.

Describe what happens both qualitatively and as quantitatively as you can.

Solution Preview

<br>Battery gives the DC (direct current) and for such case the capacitor acts as an open circuit. But, when circuit is closed or open, the capacitor gets charged or discharged. During that period some current flows through the circuit and after some time becomes zero. This current is known as transient current.
<br>So, in transition period:
<br>e (emf of battery) = i*R + v(potential drop across the capacitor)
<br>v = q/C
<br>where, q = charge on capacitor at time t
<br>C = capacitance = 15 uf
<br>i = current at time t = ...