Series Capacitance Calculator

Capacitors in series

Capacitors behave the opposite way to resistors. Put them in series and the total capacitance goes down. The same charge sits on each capacitor, but the supply voltage splits across all of them, and the result is a smaller overall capacitance than any single one in the chain.

The formula

The total capacitance C_total of capacitors in series is the reciprocal of the sum of the reciprocals of each value:

where C1, C2, C3 … Cn are the individual capacitor values.

Example

Take three capacitors in series of 4 µF, 6 µF and 12 µF:

Adding the reciprocals:

Then take the reciprocal to get the total:

So three capacitors of 4, 6 and 12 µF in series come to just 2 µF. Less than the smallest of them.

Picture them in a daisy chain, the outer plates connecting to the circuit and the inner plates joining one capacitor to the next.

Two things to keep in mind

• The total is always smaller than the lowest single capacitor in the series.
• The voltage divides across the capacitors, which is one reason series connections are sometimes used to share a high voltage across several parts.