Parallel and Series Capacitors — Definition

Definition

Imagine you have several water tanks. If you connect them one after another, so the water flows from the first into the second, and then into the third, that's like capacitors in 'series'. In this setup, the same amount of water (charge) passes through each tank, but the total height difference (potential difference) is the sum of the individual height differences across each tank.

For capacitors in series, the total capacitance decreases, becoming less than the smallest individual capacitance. This might seem counterintuitive, but think of it as increasing the effective distance between the plates, making it harder to store charge for a given voltage.

The total potential difference across the combination is the sum of the potential differences across each capacitor, while the charge stored on each capacitor is the same.

Now, imagine you connect these water tanks side-by-side, with their inlets connected to one main pipe and their outlets connected to another main pipe. This is like capacitors in 'parallel'. In this case, each tank experiences the same height difference (potential difference) because they are connected to the same two main pipes.

However, the total amount of water (charge) stored is the sum of the water stored in each individual tank. For capacitors in parallel, the total capacitance increases, becoming greater than the largest individual capacitance.

This is because connecting them in parallel effectively increases the total plate area available for charge storage, making it easier to store more charge for the same voltage. The total charge stored in the combination is the sum of the charges on each capacitor, while the potential difference across each capacitor is the same.

These two fundamental ways of combining capacitors allow engineers to tailor circuits for specific needs, whether it's to store a large amount of energy, filter out unwanted signals, or create precise timing mechanisms.