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Insight - How Capacitor works

Table of Contents:

  1. Insight - How Capacitor works
  2. Internal Structure
  3. Metal Electrodes

Written By: 

Ashok Sharma

Capacitor is a widely used electronic component. It stores electric charge and then discharges it into the circuit. It blocks the direct current and allows the alternating current to pass through it. Depending on the purpose, there are a variety of capacitors being used like ceramic, electrolytic, mylar, mica, etc. We will explore an electrolytic capacitor through this article.

Structure of a Capacitor: A capacitor contains two conductor plates which are generally made of metal and an insulator between them. This insulator also known as dielectric is made up of material like paper, plastic, ceramic or glass. The two plates are electrically connected to the external circuit with the help of two thin metal rods also known as the legs of the capacitor.
These two plates are used to store charge between them. One is connected with positive voltage and other one with negative voltage. A capacitor is characterized by the parameter capacitance. Capacitance is measured as ratio of difference of charges between the plates and total voltage drop between the plates.
C = dQ/dV
The unit of capacitance is FARAD.
Let’s have a closer look into the structure and how a capacitor is able to store charge.


Electrolyte Capacitor
The above image shows a simple electrolytic capacitor with two thin rods coming out from the cylindrical container. The capacitor is wrapped up using a plastic covering. This covering is done to label the capacitor.

Metal Container

Capacitor metal container and label
On removing the label, you can see a metal container adjoined with a rubber stand to hold the entire setup.


amazing, first time i have seen the capacitor so clearly and its fabrication...........................

nice one....and, could you also explain why it allows A.C and blocks D.C by a similar practical approach.. 

A capacitor blocks D.C. because capacitive reactance (X) is inversaly proportional to frequency of the signal passed through it.

As frequency of the D.C. is zero, so the Xc becomes infinitive for D.C.

Thats the reseon why a capacitor blocks D. C.         

excuse me,

can u tell me, what are the software required to learn in electrical and elelctronics engineering.

with their uses and purpose.

it will be very kind of you sir.



Electroic work bench

Lab view

Live wire

Circuit maker




everyone knows this

it will be helpful for explaining the structure of capacitor to the student

please upload structure of cyramic capacitor

awesome !!!

great work


Assalamualaikum guys...I m using ultrasonic sensor to make velocity counter...can any one tell me how to use ultrasonic sensor...plsssss..i don't have any information about this sensor...

thi is vey use full for the lerners

why because  its very interesting

 like a cinema

respected sir,

Pls send insite of resistor,transformer,diode,transistor,IC,SCR,LED,UJT,FET,MOSFET


realy amazing

my request to add more like how resistors, inductors etc.,, manufactured.

but really its outstanding.

great work..


article is so much interesting and knolegeble.

acha hain ..............can u tell me mr ashok what is the funtion and usage of paper capacior



              This is the first time I understand how the capacitor is designed. Keep it up. Thank you.



really amazing!!!!

awesome brooo ..... nice approach to give a pictorial view of the capacitor... U ROCKcool


can u please demystify the pattren of charging and discharging for ac as well as dc voltages..




its just great ,,, really informable,,, can you please put this kind of info of all the component as it will be great to understand in this way,,,,,,smiley

cool ...small.. structure../


great .. could you say where and all to use this capacitor .. because i am seeing this in various places


ur site infos r just mindblowing, d way u show d composition inside!!!Pls also put insite of resistor,transformer,diode,transistor,IC,SCR,LED,UJT,FET etc it wil b really of gr8 help :)

sir can u explain how it store charge in it?


sir can u pls explain how it store charge in it?

superb website for begineers

It is really helpful for the beginners.


It will be useful for anyone. there are different types of capaciter,How we know which type capaciter use  in particular circuits




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