When capacitors are in configured in parallel, the equivalent capacitance goes up. (The "equivalent" is the value of a single capacitor if it was to replace this section of a circuit. The equivalent is used instead of "total" because "total" implies that capacitors are always directly added -and that is not true for series circuits.) Capacitors in parallel add up according to the formula below.

This equation makes sense. The original formula for parallel plate capacitors showed that the capacitance goes up as the plates' area gets larger. In a parallel capacitor arrangement, that's why the equivalent capacitance increases.

The charge that resides on each plate is directly proportional to the area of the plate. A larger plate means more room fro charges to sit. Carrying this a step further, the amount of charge stored in each capacitor is proportional to the capacitance too.

By the definition of parallel components, from the video above, the voltage used up by each capacitor in parallel is the same.

Example 3

Question

Solution

What is the total capacitance of the circuit below?

Example 4

Question

Solution

What is the total capacitance of this circuit?

Capacitors in Series

Unlike capacitors in parallel, when capacitors are in series their equivalent capacitance goes down. They behave according to the formula below.

Each capacitor in series will use up a difference amount of voltage. But each capacitor in series will all have the same charge.

Example 5

Question

Solution

What is the circuit's total capacitance?

Example 6

Question

Solution

What is the circuit's total capacitance?

What is a real capacitor?

Only watch the first 2 minutes of the video.

This video is made by Makezine. (One of my favorite magazines.)