Capacitance is the ability of a system to store charge. It is de ned as charge stored per volt. Capacitors are made of two parallel metal plates separated by an insulator. We use air or a vacuum as our insulator at A-level, but in practice, dielectrics are used. Dielectrics increase capacitance because they are more insulating than air or a vacuum. We can nd the capacitance of a capacitor using:
