# What is capacitor? Working principle of it.

## Capacitor

Capacitor stores electric charge. It is looks like battery it stores energy in a different way. It is stores much energy in battery. It releases charge very faster. Capacitor is very useful that’s why it is used in all circuit boards.

It is one of the fundamental passive components. It is separately or jointly used with other circuit components such as inductor or resistor or others. But in AC Power circuit it is used in power factor correction. It is a two terminal device which stores energy in an electric field. It is consisting of two parallel plates.

They are made of conducting materials such as copper or silver or iron (mostly silver) and they are separated by a layer of dielectric material. The dielectric material is filled in between the capacitor’s terminal. Here, The dielectric material is an efficient insulator, so that it prevents electron flow across the terminal.

## Working Principle of Capacitor

Positive Q+ as Plate A and Negative Q- as Plate B,

Consider two parallel plates A and B, and A is connected with positive terminal of the voltage source and B is connected with a negative terminal of the same source. The electron flows from negative terminal and accumulates on the plate B developing negative charge, due to this the equal number of positive charges accumulate in plate A.

Here the electric field is established in the dielectric between the plates. The direction of electric field always drives electrons from the positively charged plate to positive terminal of the source. The amount of negative charge stored on plate B is equal to the amount of positive charge on the plate A. Due to this, the two plates A and B carry equal and opposite charges, since, there is a voltage across these two plates.

Let us consider voltage across the capacitor is Vc, and it is opposite that of applied voltage V. As the charge on the plate increases, the voltage across the plates also increases simultaneously. AT the same time, if the voltage across the parallel plates reaches to the source voltage V, then, there is not flow of electrons from the source.

### Symbol of the capacitor

We can measure the capacitance of the capacitor in the unit of farads. This is mentioned as ‘F’ in capacitor. his is a very large unit.

In circuit boards typically use micro-farads. It is used like letter ‘μ’ other value is voltage which we can measure in volts ‘V’. In the capacitor the voltage is the maximum value which capacitor can handle. The capacitor is rated at certain voltage it exceeds the capacitor will explode.

Microfarad capacitors mainly used in electrical power system and power factor correction circuit

The small capacitor in the range of below one microfarad Capacitors is mainly used in electronics circuit. There are many types of capacitors are in the market.

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