Capacitance in Series and Parallel:
Capacitors in Series
Let, C1, C2, C3 = capacitance of each capacitor,
V1, V2, V3 = voltage gradient across each capacitor, and
C = equivalent capacitance.
In this case, charge on each of the capacitor is same but potential difference is different.
Figure: Capacitors in Series
V = V1 + V2 + V3 (as capacitors are in series)
or Q/C = Q/C1 + Q/C2 + Q/C3 ⇒ 1 /C = 1/C1 + 1/C2 + 1/C3
⇒ C = C1C2C3 / (C1 C2 + C2 C3+ C3 C1)
Capacitors in Parallel
In this case, potential difference is same but charge is different on each capacitor
∴ Q = Q1 + Q2 + Q3
or CV = C1 V + C2 V + C3 V
or C = C1 + C2 + C3
Figure: Parallel Capacitors