A capacitor stores electrical energy in an electric field created between two conductive plates separated by a non-conductive material called the dielectric. To charge a capacitor, you need to supply a voltage difference across the plates. This creates an electric field and stores energy in the field. The charging process continues until the voltage across the plates reaches the value of the supply voltage.
To discharge a capacitor, you need to create a path for the stored electrical energy to flow out of the capacitor. This can be done by connecting a resistor in series with the capacitor and then connecting the circuit to a power source. The voltage across the capacitor will start to drop as the stored electrical energy flows through the resistor and into the power source. The discharge process continues until the voltage across the capacitor has dropped to zero.
It’s important to use the correct values for the supply voltage and discharge resistor to avoid damaging the capacitor or the surrounding components. The time constant of the circuit (the product of the resistance and capacitance) determines the rate of charge or discharge of the capacitor. A larger time constant means that the capacitor will take longer to charge or discharge, while a smaller time constant means that it will charge or discharge more quickly.
Charging a Capacitor:
The Following steps must be followed while Charing a Capacitor.
- Connect the Capacitor: Connect the positive terminal of the power source to one plate of the capacitor and the negative terminal to the other plate.
- Initial Voltage: Initially, the voltage across the plates of the capacitor is zero.
- Charge Flow: As soon as the power source is connected, a flow of charge starts from the positive terminal to one plate of the capacitor and from the other plate to the negative terminal.
- Electric Field: This flow of charge creates an electric field between the plates of the capacitor. The electric field stores energy.
- Voltage Increase: As more and more charge flows into the capacitor, the voltage across its plates starts to increase.
- Plate Charge: The amount of charge on each plate of the capacitor increases as the voltage increases. The charge stored in the electric field also increases.
- Charge Equilibrium: The flow of charge stops when the voltage across the plates of the capacitor becomes equal to the supply voltage. At this point, the capacitor is fully charged and the electric field has reached its maximum strength.
Discharging a Capacitor:
The Following Steps must be followed while Discharging a Capacitor.
- Connecting the Circuit: Connect a resistor in series with the capacitor. Connect the positive terminal of the power source to one plate of the capacitor and the negative terminal to the other plate through the resistor.
- Initial Voltage: Initially, the voltage across the plates of the capacitor is equal to the supply voltage.
- Charge Flow: As soon as the power source is connected, a flow of charge starts from one plate of the capacitor to the positive terminal of the power source and from the negative terminal to the other plate.
- Voltage Decrease: The voltage across the plates of the capacitor starts to decrease as the stored energy in the electric field flows through the resistor and into the power source.
- Plate Charge: The amount of charge on each plate of the capacitor decreases as the voltage decreases. The charge stored in the electric field also decreases.
- Discharge Equilibrium: The flow of charge stops when the voltage across the plates of the capacitor becomes zero. At this point, the capacitor is fully discharged and the electric field has disappeared.
“It’s important to note that the rate of charge or discharge of a capacitor is determined by its capacitance and the resistance of the circuit. A larger capacitance means that the capacitor can store more energy and therefore takes longer to charge or discharge. A smaller resistance means that the flow of charge is faster and therefore the capacitor charges or discharges more quickly.“