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An Introduction to Capacitor, Capacitance, Types and Real life applications

Writer's picture: NIVVETHA CHELLAPPANNIVVETHA CHELLAPPAN

Updated: Sep 15, 2024


What is a capacitor?


A capacitor is a passive, two-terminal electronic component. A capacitor has the ability to store electrical energy. A capacitor is otherwise called an electric condenser. Because it stores electrical energy in an electrical field when we bring two conductors close but insulated from each other.


Capacitor
Capacitor

While designing an electrical and electronic circuit, the capacitor is predominantly used. It plays a crucial role in different kinds of embedded applications. There is a wide range of capacitors available on the market, distinguished mainly by the type of dielectric material used in the plates.


This is the symbol of capacitor
Capacitor Symbol

What is capacitance?


Capacitance is the electrical capacity of the capacitor. Capacitance is a measure of the amount of electrical energy stored in a capacitor when it is charged to a voltage of 1 volt. It is typically measured in units of Farad (F).



What are all the factors that affect capacitance?


Surface area of the plates


  • The higher the surface area, the higher the capacitance value.


Distance between the plates


  • The lower the distance, the higher the capacitance value.


Dielectric Medium


  • Dielectric is the type of material that separates the two plates.

  • The higher the dielectric's permittivity, the higher the capacitance value


C = ε A/d


C = capacitance of the capacitor

ε = permittivity of the material between two plates

A = surface area of each plate

d = distance between two plates



Construction of a Capacitor


A parallel-plate capacitor is considered one of the simplest forms of a capacitor. It is constructed by placing two metal plates parallel to each other, separated by a distance.


Let's say a voltage source is connected across a capacitor. The positive terminal of the voltage source is connected to the positive terminal of the capacitor, and the negative terminal of the voltage source is connected to the negative terminal of the capacitor. Then the amount of energy stored in the capacitor is directly proportional to the voltage that is applied.



Q = CV


Where Q =charge, C = capacitance, and V = voltage.


Classification of capacitors


Based on the structure, the capacitors are classified as

  • Fixed Capacitors

  • Variable capacitors

  • Trimmer Capacitors


Based on the polarization, the capacitors are classified as

  • Polarized capacitors

  • Non-polarized capacitors


Polarized capacitors


  • Polarized capacitors are electrolytic capacitors. This type of capacitor is a crucial part of an electronic circuit.

  • It is responsible for providing high capacitive density.


Non-polarized capacitors


  • Non-polarized capacitors are used in pure AC circuits.

  • As these are non-polarized capacitors, they find applications in DC circuits.

  • The spillage current is low in this capacitor.



Series & Parallel Connection


Capacitors connected in series


When capacitors are connected in series, the amount of charge stored is the same on each plate, but their plates contain different voltages.


Total capacitance in series 1/C = 1/C1 +1/C2+ 1/C3+.....+1/Cn