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Difficulty: EasyCapacitors

Once a capacitor placed in a direct current (DC) circuit reaches a fully charged state, how does it affect the continuous flow of current in that branch?

  1. It blocks direct current completely because the accumulated charge creates an opposing voltage equal to the supply voltage.Answer
  2. B
    It allows direct current to conduct freely because the dielectric spacer functions as an electrical conductor.
  3. C
    It transforms the incoming direct current into an oscillating alternating current output.
  4. D
    It sustains ongoing current flow by continuously storing energy within a magnetic field.

Answer

A fully charged capacitor completely blocks the continuous flow of direct current by acting as an open circuit.
The correct choice explains that as a capacitor charges, its plate voltage rises until it matches the applied direct current source voltage. At this equilibrium point, no net voltage difference exists to move additional electrons through the circuit branch, completely stopping current flow and causing the capacitor to act as an open circuit to steady DC.

Step-by-Step Solution

1
Identify the charging behavior of a capacitor connected to a DC source.
Current flows initially as electrons accumulate on one plate and leave the other, creating a potential difference across the dielectric.
Capacitors respond to changes in voltage by charging until their terminal voltage matches the applied source voltage.
2
Determine the state of the circuit when the capacitor is fully charged.
The voltage across the capacitor equals the supply voltage (VC=VSV_C = V_S), so the net voltage driving current becomes zero (I=0I = 0).
With no potential difference remaining across the circuit resistance, current ceases entirely, meaning the fully charged capacitor acts as an open circuit to DC.

Key Concept

DC Blocking Behavior of Capacitors
Estimated Time:45s
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Topics

Capacitors

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