Capacitor is one of the passive components used in electronic circuits. It acts as a temporary battery. Its main function is to store electricity and release it whenever required. They are also called condensers.
Capacitors have a property called capacitance, which tells how much charge it can store. Capacitance is measured in unit called Farad, named after scientist Michael Faraday.
However, Farad is a bigger unit. We use smaller measurement units such as:
1 Milli farad (mF) = 10-3 Farad
1 Microfarad (µF) = 10-6 Farad
1 Nano farad (nF) = 10-9 Farad
1 Pico farad (pF) = 10-12 Farad
Capacitors are constructed using two conducting plates which are not connected and are separated by some insulating material like air, paper, mica, ceramic etc.
The insulating material used is called dielectric and capacitor is named after the type of dielectric used in its construction. For example, if the dielectric used is mica than the capacitor is called mica Capacitor.
When current passes through a capacitor, charge accumulates on conducting plates. The charge cannot move because of insulating material present. Thus capacitor acts as a temporary battery. Capacitor is said to be charged in this state.
When a charged capacitor is placed in a circuit, the accumulated charge finds alternative path and it starts flowing, releasing the charge from conducting plates. In this state, the capacitor is said to be discharged.