What is Capacitors? How is it Work?

Capacitors are mechanical devices that store energy as an electric charge by placing an insulator between the two conductors placed side by side. It is reused by storing energy from a source such as a battery to a capacitor. Van Muschen Broek of the University of Leiden invented this mechanical technique of storing charges in 1746 AD.


Capacitors are made by placing an insulator material such as air, glass, plastic, etc. in the space between the two conductors. The insulator material in the middle of it is dielectric. The amount of charge required to increase the voltage per unit of a conductor is the capacitance of that conductor. Capacitance is expressed by C. Its unit is Faraday (F).

One farad is much larger, about the equivalent of 6,280,000,000,000,000,000 electrons. So microfarads (uF) and picofarads (pF) are used in practical cases.  One micro farad equals 0.000,001 farads and one picofarad equals 0.000,000,000,001 farads. If Q amount of charge is required to increase the voltage V amount of a conductor, Q / V amount charge will be required to increase the voltage (V) unit amount.



One Farad

If a coulomb (1C) charge is required to increase the voltage of a conductor by one volt (1V), then the capacitance of that conductor is called one farad (1F). When a capacitor is charged, an electric field arises between the two conductors. The field applies force to any charged object located in the electric field. On a negatively charged object, this force acts on the positive side of the capacitor. The insulator material between the two conductors is affected by this electric field and the charged particles (such as electrons) located in this material are forced to move towards the positive side of the conductor under the influence of this ball. As a result, the orbits of the electrons around the nucleus expand slightly. As the orbit of the electron becomes larger, the energy level of the electron also increases. And thus the capacitor stores energy.

The capacitor is charged when there is a potential difference between the capacitor plates and discharged when there is no potential difference.

Capacitor Types

  • Fixed Capacitor
    • Paper Capacitor
    • Plastic Film Capacitor
    • Poly Carbonate Capacitor
    • Mica Capacitor
    • Ceramic Capacitor
    • Polyester Capacitor
    • Skrillex Capacitor
    • Electrolytic Capacitor
    • Tantalum Capacitor
  • Variable Capacitor
    • Trimmer Variable Capacitor
    • Padder Variable Capacitor
    • Gang Variable Capacitor
  • According to polarity
    • Polarized Capacitor
    • Non-Polarized Capacitor

The stored energy of a charged capacitor depends on the charge stored on the capacitor, the voltage difference between the two layers of the capacitor, and the capacitance of the capacitor. Capacitors are mainly used to hold a charge. It is used in filter circuits, tuning work.

Capacitors are connected in two ways:

  1. Series connection
  2. Parallel connection

Series connection

The connection of the capacitor to the first terminal of the second capacitor with the second terminal of the first capacitor, the first terminal of the third capacitor with the second terminal of the second capacitor, and so on is the series connection of the capacitors.

If the + Q charge from a power source is supplied to the first layer of the first capacitor, it will occupy the -Q charge on the inner surface of the other layer, and the + Q charge will flow to the first layer of the second capacitor. This process keeps repeating. Thus one sheet of each capacitor receives the charge + Q and the other the charge -Q. If the voltage difference between the two sheets of capacitors is V1, V2, V3, etc., the voltage difference between the first sheet and the last sheet in the series connection will be, V = V1 + V2 + V3.

Parallel connection

The connection in which the positive terminals of the capacitors are connected at one end and the negative terminals at the other end are called the parallel connection of the capacitor. Since the two terminals of the capacitor are connected to the two terminals of the source, so each capacitor will be charged at the same voltage. Given the + Q charge from the source, if the amount of charge on the capacitors is Q1, Q2, Q3 respectively, then the total charge will be Q.


Read More: How to Use Electrical Tools and Equipment


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