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How does a capacitor behave in a DC circuit initially?

Initially, a capacitor behaves as an open circuit in a DC circuit.

When a DC voltage is applied to a capacitor, the capacitor charges up until the voltage across it becomes equal to the applied voltage. During this charging process, the capacitor behaves as an open circuit, meaning that no current flows through it. This is because the capacitor acts as a temporary storage device for electric charge, and it takes time for the charge to build up on the plates.

To understand more about how a capacitor stores charge, consider the principles of capacitance of isolated spherical conductors.


Once the capacitor is fully charged, it behaves as a short circuit, allowing current to flow through it. However, the current flow is only temporary, as the capacitor discharges and the voltage across it decreases. The rate of discharge depends on the capacitance of the capacitor and the resistance of the circuit. To see how the voltage changes during this process, explore discharging a capacitor - graph analysis.

In summary, a capacitor behaves as an open circuit initially in a DC circuit, as it charges up and stores electric charge. Once fully charged, it behaves as a short circuit, allowing current to flow temporarily before discharging. Understanding the behaviour of capacitors in DC circuits is important in many applications, such as power supplies and filters. For more insights into how energy is stored and dissipated in a capacitor, see electric potential energy and graphs and equipotential surfaces.

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