Take a vessel of 2 litre and we can pour the water into the vessel up to 2 litre. The capacity of the vessel is only 2 litre. Incase of 5 litre vessel, it's capacity to store water is up to 5 litre.
The capacity of vessel can be compared to capacitor, since a component is needed to have the capacity to store charges.
Capacitor, a passive electronic component, is nothing but a parallel conductors separated by a dielectric. When voltage is applied between the plates of parallel conductors, electric field is developed in the dielectric.This electric field stores electrical energy or charge. Capacitor's ability to store charge is known as capacitance (C).
Capacitance can be calculated from the ratio of amount of charge (Q) stored on the capacitor to the voltage applied.
C = Q / V
The symbol of a capacitor :
Capacitance is measured in farads.
Capacitors make most of its application in electronic circuits. Capacitors is used to allow alternating current (AC) whereas it is used to block direct current in several circuits. The value of capacitors commonly used are in the range of microfarads (µF), nanofarads(nF) and picofarads (pF).