Edited by Sim, Jen Moreau, SarMal

Capacitors consist of two terminal electrical components and are one of the most essential components utilized in electricity. As the name implies, capacitors store energy in the form of an electrical charge producing a potential difference (Static Voltage) across its plates[1].

Was this helpful? Yes | No| I need help


The simplest capacitor consists of two parallel metal plates placed face to face and separated by air or another insulating material. This medium between the 2 plates is called dielectric.

Charging of a Capacitor

A capacitor is commonly charged by connecting its plates to the opposite terminals of a battery. In this way, some electrons are transferred through the battery from the positive plate to the negative plate. Charge "+Q" and "-Q" appear on the plates. The mutual attraction between the charges keeps them bound on the inner surface of the two plates and thus the charge remains stored in the capacitor even if the battery is removed. The larger the voltage of the battery, the greater the charge on the capacitor.

Was this helpful? Yes | No| I need help
Q ∝ V
Where 'C' is a constant depending on the geometry of the capacitor. It is known as the capacitance of the 


The charge stored per unit potential difference between the plates is called its capacity or capacitance. It is denoted by "C".

As Q= CV
C= Q/V 
If V=1 volt then C=Q
The capacitance 'C' depends on:
 a. The area of the plates
 b. The distance between the plates 
 c. The medium between the plates.

Note that capacitance is always a positive quantity. The SI Unit of the capacitance is "Farad" after the scientist Michael Faraday.


The capacitance of a capacitor is said to be one farad if a charge of one coulomb, given to one of the plates, produces a potential difference of one volt between them. The farad is a very large unit. Its sub units are microfarad (10-6 farad) and pico farad (10-12 farad).

Was this helpful? Yes | No| I need help

Combination of Capacitors

Two or more capacitors are often connected in circuits in several ways. These capacitors can be combined either in series or in parallel circuits.

  1. 1
    Series Combination of Capacitors
    When the capacitors are connected in series: the charge remains undivided, and the voltage or potential difference (P.D) is divided into parts, as shown in the figure.
    1. Consider two capacitors. Say "C1" & "C2" are joined to a battery of voltage "V".
    let "V1" & "V2" be the potential difference across each capacitor.
    So V= V1+V2
    Or Q/C= Q/C1 + Q/C2
    So 1/C= 1/C1 + 1/C2 
    or 1/C= C1+C2/ C1C2
    C= C1C2/C1+C2
    Where 'C' is the equivalent capacitance of the combination
    1/C= 1/C1+1/C2+1/C3+…….+1/Cn
    Was this step helpful? Yes | No| I need help
  • There is only one path for the flow of charge in a series combination.
  • The sum of the individual voltages is equal to the total voltage of the source.
  • The reciprocal of equivalent capacitance is equal to the sum of the reciprocals of the individual capacitors.
  • Parallel Combination of Capacitors. When capacitors are connected in such a way that the potential difference remains undivided while the charge is divided into parts "P" is called parallel combination see the figure.
Was this helpful? Yes | No| I need help

Consider two capacitors

"C1" & "C2" 
let the maximum charge on the two capacitors be represented by 
"Q1" and "Q2"
Q= Q1+Q2----------- (1)
As Q=CV   >    Q1= C1V & Q2= C2V
So Equation (1) >   CV= C1V+C2V    
> C= C1+C2 ------------ (2)
Where 'C' is the equivalent capacitance and C1,C2 are individuals capacitors. Now if 
there are n- number of capacitors, then 
Ceq= C1+C2+C3+C4……….+Cn
  • There are various paths for the flow of charges.
  • The potential difference across each capacitor is the same, i.e
  • The equivalent capacitance is equal to the sum of the individual capacitors. i.e Ceq=

Types of Capacitors

Capacitors are of various types, sizes, and shapes. Generally, capacitors are of the following two types.

  1. 1
    Fixed Capacitor
    A capacitor whose parts or components are fixed is called a fixed capacitor. E.g paper capacitors, mica capacitors etc.  
    1. Paper capacitors consist of two aluminum foils between which greased paper or a plastic sheet is used as a dielectric. These are then rolled into a cylindrical shape.
    Was this step helpful? Yes | No| I need help
  2. 2
    Variable Capacitor
    The capacitor whose capacity can be changed by changing the area of the plates, or by changing the distance between the plates, is known as a variable capacitor.
    1. It is usually a combination of many capacitors, and the air is used as a dielectric. Variable capacitors are usually used in the circuits of radio tuning. By changing the capacity, different radio stations are tuned.
    Was this step helpful? Yes | No| I need help

Referencing this Article

If you need to reference this article in your work, you can copy-paste the following depending on your required format:

APA (American Psychological Association)
Capacitors. (2017). In ScienceAid. Retrieved Sep 24, 2023, from

MLA (Modern Language Association) "Capacitors." ScienceAid, Accessed 24 Sep 2023.

Chicago / Turabian "Capacitors." Accessed Sep 24, 2023.

If you have problems with any of the steps in this article, please ask a question for more help, or post in the comments section below.


ScienceAid welcomes all comments. If you do not want to be anonymous, register or log in. It is free.

Article Info

Categories : Physics

Recent edits by: Jen Moreau, Sim

Share this Article:

Thanks to all authors for creating a page that has been read 318 times.


Thank Our Volunteer Authors.

Would you like to give back to the community by fixing a spelling mistake? Yes | No