Experiment 10 - Capacitors in Series II

What is the total capacity of a series circuit with two capacitors of different capacity? Just try it out....

Replace the capacitor C2 from the last experiment by a 10 μF capacitor

Circuit with two series-connected electrolytic capacitors. (Enlarge)

Circuit diagram of the circuit with two series-connected electrolytic capacitors.

The LEDs light up a little shorter than what you expect from a 10 μF capacitor. And indeed, you calculate the total capacity as...

C_total = ( C₁ * C₂ ) / ( C₁ + C₂ ) = ( 100 μF * 10 μF ) / ( 100 μF + 10 μF ) = 9 μF

The total capacity of a series circuit is always smaller than the smallest capacity in the circuit. If you replace the capacitor C2 by the 47 nF ceramic capacitor, you get a total capacity of slightly less than 47 nF.

If you want to understand the reasons, you should have a look at the topic capacitor in physics.

But first, enough is said about the properties of capacitors. In the following experiments you see where and how capacitors are used.