It will not be wrong to say that one can find capacitors in almost every sort of electronic circuits from analogue to logic ones. The selection of a suitable capacitor is having great significance as it can affect the functionality of a circuit remarkably. It means that the whole circuit may not function effectively if a suitable capacitor is not placed. In the upcoming posts we will understand the fundas of capacitor. But first things first. Lets discuss the theory initially in this post “Capacitor Theory”.

Capacitor is a basic electronic component which accumulates electrical charge. When an electric power is provided to the capacitor, the capacitor starts accumulating the electrical charge. As soon as the power goes off, it slowly discharges the accumulated charge. The Various symbols of Capacitors are :

A capacitor contains two conductor plates well insulated by a thin layer of Dielectric. The conductor plates may be metal foil or solid metal plates. The dielectric may be any insulating material ranging from vacuum, air, paper, plastics, ceramic etc. The main factor behind categorization of capacitors into its various types is the selection of this dielectric material.

Inner construction of a capacitor

Capacitance :

Capacitance has a very important role in capacitor theory. The capacitance of a capacitor is its charge storing capability per unit volt. It is measured in Farad. Capacitance of Capacitor can be derived as:

Capacitance, C = Total charge stored/Volt

» C =

» Farad =

Hence, A Farad can be defined as :

A capacitor is said to have a capacitance of one ‘Farad’ when one coulomb of electric charge can be stored in it by applying one volt from a power source.

Here, don’t underestimate one Farad of electric charge. One Farad of charge is beyond limit for most of the electronic circuits. It is therefore, capacitors are commonly available in much smaller capacitance value known as Micro Farad (µ)[ 10-6], Nano farad (n) [ 10-9]and Pico Farad (p) [ 10-12].