Why pulsed DC passes through a capacitor?
Zero volts doesn't mean zero current. Assume your circuit looks like this:







simulate this circuit &ndash; Schematic created using CircuitLab

When the switch turns on (connects to 10V), current flows to the right and charges the capacitor up to 10V. Once that happens, the current stops*. When the switch turns off (connects to ground/0V), current flows to the left and discharges the capacitor. (The capacitor acts like a voltage supply.) The current stops when the capacitor reaches 0V.

Short version: Pulsed DC is actually AC.

*The charge and discharge are actually exponential decays, so mathematically, the current never really stops. It approaches zero asymptotically at a rate determined by the resistance and capacitance.