Capacitance (AQA A-Level Physics): Revision Notes

7.4.1 Capacitance

Definition

Capacitance $( C )$ is a measure of a capacitor's ability to store electric charge. Specifically, it is defined as the amount of charge $( Q )$ that a capacitor can store per unit of potential difference$( V )$ across its plates. The relationship between charge, capacitance, and potential difference is given by the formula:

Where:

• $C$ is the capacitance measured in farads ($F$),
• $Q$ is the charge in coulombs ($C$),
• $V$ is the potential difference across the capacitor in volts ($V$). Capacitance is essentially an indicator of how much electric charge a capacitor can hold at a given voltage. Capacitors are commonly used in circuits to store energy temporarily, philtre signals, and manage power supply in electronic devices.