Explanation:

• Capacitors do not allow DC to pass through because, in a DC circuit, the capacitor charges up to the supply voltage and then acts as an open circuit, blocking any further current flow.
• However, capacitors allow AC to pass through because the constantly changing voltage in an AC circuit causes the capacitor to charge and discharge, thus allowing current to flow.

Key Points:

• Capacitors block DC.
• Capacitors allow AC to pass by offering a certain reactance depending on the frequency of the AC signal.