How do capacitors work in AC circuits?
Alternating currents periodically reverse direction and as a result the capacitor plates also change polarity. It is charged and discharged continuously.
In an alternating current circuit, due to periodic change of direction and pulsating value of the electric current, the capacitor plates continue to charge and discharge and then get charged with opposite polarity and again getting discharged and thus continuing the cycle.
One practical application is that when a capacitor is connected in parallel with a working circuit, it gets charged to the maximum alternating voltage. When the source voltage decreases till zero and then increases in the opposite direction, during that period, the capacitor discharges and supplies the power to the working circuit thereby maintaining constancy of the magnitude of voltage to the appliance connected in parallel with it.