Capacitance is a fundamental electrical property that describes the ability of a system of conductors and insulators to store electric charge when a voltage difference (potential difference) exists between them. In simpler terms, capacitance measures how much electric charge can be stored in a capacitor for a given voltage.
A capacitor is a passive electronic component designed specifically to store and release electrical energy. It consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied across the plates, electric charges of opposite polarity accumulate on the plates. The amount of charge stored on the plates is directly proportional to the applied voltage and the capacitance of the capacitor.
Mathematically, capacitance (C) is defined as the ratio of the amount of charge (Q) stored on the plates to the potential difference (V) between the plates:
C = Q / V
The SI unit of capacitance is the farad (F), named after the physicist Michael Faraday. One farad is defined as the capacitance of a capacitor that stores one coulomb (unit of electric charge) of charge when a potential difference of one volt is applied across its plates. Capacitors used in most everyday electronic applications have capacitance values typically measured in microfarads (μF) or picofarads (pF).
Capacitance plays a crucial role in various electronic circuits and devices, including filters, oscillators, energy storage, and coupling between different circuit elements. It affects the behavior of a circuit by influencing how quickly voltage changes across the capacitor in response to changes in current or how a circuit responds to different frequencies.