Stackor

Meet Stackor, two capacitors who stand side by side and store more together than either could alone.

A capacitor stores charge on two conducting plates separated by a gap. When two capacitors are connected in parallel, both are wired across the same two points, so each one sees exactly the same voltage from the supply.

Because the voltage is shared, the charges simply add up, and so does the capacitance: C = C₁ + C₂. Put a 10 μF capacitor in parallel with a 22 μF capacitor and the pair acts like a single 32 μF capacitor. Connected to a 9 V battery, the pair holds 32 × 10⁻⁶ × 9 ≈ 2.9 × 10⁻⁴ C of charge.

In parallel it is like making the plates bigger, which always increases the stored charge for the same voltage.

This is the opposite of resistors, where adding them in parallel lowers the total. Engineers use parallel banks of capacitors to smooth power supplies and to store bursts of energy.