ABSTRACT
The chapter examines capacitance and state its unit. A capacitor is an electrical device that is used to store electrical energy. The capacitor is a widely used electrical component and it has several features that make it useful and important. A capacitor can store energy, so capacitors are often found in power supplies. Capacitors are used for timing, for smoothing, for coupling, for filtering, for tuning, and for storing energy. Capacitors are also used in logic circuits, primarily for providing decoupling to prevent spikes and ripple on the supply lines which could cause spurious triggering of the circuits. A capacitor has a voltage that is proportional to the charge that is stored in the capacitor, so a capacitor can be used to perform interesting computations in op-amp circuits. Circuits with capacitors exhibit frequency-dependent behaviour so that circuits that amplify certain frequencies selectively can be built. Every system of electrical conductors possesses capacitance.
