Charging a capacitor
When a capacitor is connected to a DC circuit, current flows in the circuit for a time period until the capacitor is charged. When the capacitor is charged current ceases to flow. The capacitor, when charged, can be disconnected from the circuit and retain its charge. The following five diagrams and graphs show the charging of a capacitor over a five second period.
When the capacitor is initially connected to the DC supply the:
- current flow starts at its maximum and gradually decreases to zero
- voltage across the capacitor starts at zero and rises to the supply voltage.
The charging process takes a time period. The length of time taken to charge depends on the size of the capacitor and the resistance in the circuit.