How to Store a Charge in a Capacitor

A capacitor stores an electrical charge between two conductors (plates) separated by an insulator (dielectric). This is similar to a battery, although a capacitor is used only for temporary storage of the charge. The following steps will show how to store a charge in a capacitor.

Difficulty: Moderate

Instructions

1. Use a capacitor in a simple circuit for demonstration purposes. Turn the power supply off, attach the power supply's positive terminal to the positive terminal of the capacitor and connect the power supply's negative terminal to the negative terminal of the capacitor.

2. Adjust the voltage level of the power supply to match the capacitor's requirements. It needs to be high enough to store a charge but low enough so that the capacitor is not damaged.

3. Turn the power supply on and back off after the capacitor is charged. Unlike batteries, capacitors can be charged quickly. Capacitors suitable for use in home electronics require power for only an instant to become fully charged.

4. Detect when a larger capacitor is fully charged. Insert a light bulb in a DC circuit between the negative terminal on the battery and the negative terminal on the capacitor. The bulb will be fully lit when the capacitor is discharged. As the capacitor becomes charged, the bulb should dim until it goes out completely, indicating it is fully charged.

5. Charge a capacitor from the power supply to maintain power during the loss of the power supply. This application is commonly used to preserve volatile memory while batteries are being replaced, as is the case in a computer.

Resources

• More about capacitors at The Gear Page