Which component blocks direct current and passes alternating current?

Which component blocks direct current and passes alternating current?

• A. Capacitor
• B. Battery
• C. Buzzer
• D. Conductor

Answer: (A)

Capacitors block direct current but pass alternating current. When a DC voltage is applied, a capacitor charges up and then the current drops to zero because the dielectric prevents steady flow of charge. With alternating current, the voltage across the capacitor keeps changing, so the plates continuously charge and discharge, creating a current flow even though there’s no physical path for electrons to traverse the dielectric. This is why capacitors are used to block DC components while allowing AC signals to pass. The other options don’t fit: a battery provides DC and doesn’t block it, a conductor lets both DC and AC pass, and a buzzer is an active device rather than a passive component that selectively blocks DC and passes AC.

Capacitors block direct current but pass alternating current. When a DC voltage is applied, a capacitor charges up and then the current drops to zero because the dielectric prevents steady flow of charge. With alternating current, the voltage across the capacitor keeps changing, so the plates continuously charge and discharge, creating a current flow even though there’s no physical path for electrons to traverse the dielectric. This is why capacitors are used to block DC components while allowing AC signals to pass. The other options don’t fit: a battery provides DC and doesn’t block it, a conductor lets both DC and AC pass, and a buzzer is an active device rather than a passive component that selectively blocks DC and passes AC.