What does capacitance measure in an electrical system?

Capacitance measures the ability of a component, specifically a capacitor, to store electric charge in an electrical system. It quantifies how much charge can be stored per unit of voltage applied across the capacitor's terminals, expressed in farads (F). When a voltage is applied to a capacitor, it causes positive and negative charges to accumulate on its plates, thus storing energy in the electric field created between those plates. The capacitance value indicates the efficiency of this charge storage capability, making it a vital parameter in various electronic applications, such as filtering, timing, and energy storage.

The other options do not accurately describe capacitance. The resistance to electric current pertains to resistive components rather than capacitive behavior. Changing voltage levels is often a function of transformers or specific circuits, not directly related to capacitance. Amplifying signals generally refers to the function of amplifiers, which are quite different from capacitors responsible for charge storage.