what is a capacitor

What is a Capacitor 22

[otw_is sidebar=otw-sidebar-1]what is a capacitor,Types of Capacitorhi I hope you all are fine. this is the tenth article(Types of Capacitor) in the series on the introduction to the basic electronic components. In the previous article I have discussed the basics of the Varactor diode. In this article I will discuss the capacitor.

After reading this post the reader will be able to learn about the basics of the capacitor, construction of the capacitor, working and finally the application of the capacitor. So sit back, keep reading and enjoy learning.

What is a Capacitor

The capacitor is one of the three basic electrical components other two being the resistor and inductor. Capacitor is the two terminal passive electrical component, that implements the capacitance in the circuit. By passive it means that like the resistor the capacitor also consumes the net power. Two basic types of the capacitor are polar and non-polar. The schematic symbol of the capacitor is as shown in the following image:

Symbol of the capacitor

The capacitors are categorized in various categorize on the basis of the construction, material used, temperature coefficient etcetera. For example there are ceramic capacitors, electrolytic capacitors, tantalum capacitor.(Types of Capacitor)



Construction of Capacitor:

The simplest capacitor is the parallel plate capacitor in which two thin metallic conductors are placed in parallel to each other. The conductors are kept at particular distance and insulation material known as dielectric is placed in between them. The capacitance of the capacitor depends on the area of the metallic conductors, distance between them and permittivity of the dielectric material.


The ratio of the change in electric charge to the corresponding change in the applied voltage is defined as the capacitance of the system. The capacitance of the capacitori is measured in Farad.


The unit used to measure the capacitance of the capacitor is the Farad. The capacitance of the system is said to be one Farad if the electric charge of one coulomb exist on it when electric potential of one volt is applied across its ends. The basic construction of the capacitor is as shown in the following figure:

what is a capacitor,construction of the capacitor


Working of the capacitor:

As mentioned earlier that the capacitor implements the capacitance in the system and capacitance is directly proportional to the surface area of the conductor plates and inversely proportional to the distance between the plates. As the distance between the metallic plate increases the capacitance reduces and by reducing the capacitance the it means that the ability of the capacitor to store charge reduces. The expression of the capacitance is as shown in the following figure:

capacitor formula



Capacitor Formula


The Capacitor Formula is below

q = CV


= charge
C = capacitance
V = voltage


Applications of the Capacitor:


The capacitor is commonly employed electronic component in electronic circuits. One can find capacitor in almost every electronic due to its vast applications. Some of the common applications of the capacitors are listed in the following:

  • Capacitor is used as the decoupling capacitor in which it is connected to the power supply to filter the noise.
  • The capacitors are used for AC coupling in the circuits where the DC component of the signals is to be blocked.
  • The capacitor is also employed for bootstrapping.
  • The capacitors are in active filter circuit design.
  • The capacitors are also used in the passive filter circuits.

Types of Capacitor

I hope this article would be helpful for you. I have discussed the basics of the capacitor. That is all for now I hope this article would be helpful for you. In the next article I will come up with more interesting engineering topics. Till then stay connected, keep reading and enjoy learning.


In the previous article I have discussed about basics of the Introduction to Photodiode


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