A very common use of a capacitor is to provide little opposition for ac voltage but to block any dc voltage.

Question

Quizplus · Accepted Answer

Capacitors allow alternating current (AC) to pass through while blocking direct current (DC) because they charge up to the applied DC voltage level, effectively stopping the flow of DC, but they can pass AC as their impedance (opposition to current) decreases with increasing frequency.

A Very Common Use of a Capacitor Is to Provide