Capacitors in Series

Capacitors in Series

• Consider the three capacitors in series connected across the applied voltage V as shown in the Fig. 5.11.1. 

Suppose this pushes charge Q on C1 then the opposite plate of C1 must have the same charge. This charge which is negative must have been obtained from the connecting leads by the charge separation which means that the charge on the upper plate of C2 is also Q. In short, all the three capacitors have the same charge Q.

• If an equivalent capacitor also stores the same charge, when applied with the same voltage, then it is obvious that,

It is easy to find V₁ V₂ and V₃ if Q is known.

For ‘n' capacitors in series,

Key Point : For all the capacitors in series, the charge on all of them is always same, but the voltage across them is different.

Review Question

1. Deduce the expression for joint capacitance of two C1 capacitors and C2 when connected in series.