Capacitance is a fundamental concept in physics and electronics that refers to the ability of a capacitor to store an electric charge. A capacitor is a two-terminal electronic component that consists of two conductive plates separated by an insulating material called a dielectric. When a voltage is applied across the plates, an electric field is established, and the capacitor stores electric charge on its plates.
The capacitance (C) of a capacitor is defined as the ratio of the amount of charge (Q) stored on one plate to the potential difference (V) between the plates:
Capacitance (C) = Charge (Q) / Voltage (V)
The unit of measurement for capacitance is the farad (F), named after the English physicist Michael Faraday. One farad is defined as the capacitance of a capacitor that stores one coulomb of charge when a potential difference of one volt is applied across its plates. In practical electronic circuits, capacitances are often expressed in smaller units such as microfarads (μF), nanofarads (nF), and picofarads (pF), which are fractions or multiples of the farad:
1 farad (F) = 1 coulomb (C) / 1 volt (V)
1 μF (microfarad) = 10^-6 farads
1 nF (nanofarad) = 10^-9 farads
1 pF (picofarad) = 10^-12 farads
Capacitance plays a crucial role in various electronic applications, including energy storage, signal filtering, and timing circuits.