Capacitance is a property of charge storage exhibited by two conducting surfaces separated by an insulating medium when supplied from a voltage source. The capacitor is a device used to store charge. It consists of two conducting surfaces called electrodes separated from each other by a dielectric medium.
Definition of capacitance
Symbol of capacitor
Unit of capacitance
Current through a capacitor
Voltage across a capacitor
V = 1/c∫i.dt + v(0) ——————–(2)
Key points to be noted about capacitors:
- From equation (1) it is evident that the current through an inductor varies as a function of voltage. Therefore if the voltage remains constant, the current through the capacitor will become zero. Hence a capacitor acts as an open circuit for DC.
- Even if the current through a capacitor is zero, the capacitor stores a finite amount of energy.
- A pure capacitor never dissipates energy, but stores it the form of the electric field. But in practice, capacitors dissipate a small amount of energy due to its internal resistance.
Problems based on capacitance.