Best Tutorial on Capacitor

In this tutorial we are going to learn below of capacitor.

1. Why and how to use

2. Capacitance

3. Symbols

4. Types

5. Units and formula

6. Applications and Examples

  • Capacitor – A passive two terminal electrical component that stores electrical energy in an electric field.
  • Construction – A capacitor is made up of two electric plates. With a dielectric material in between the plates. When you apply a voltage over the two plates. an electric field is created. Positive charge will collect on one plate and negative charge on the other
  • Capacitance – The amount of electrical energy a capacitor can store is called its capacitance.

Capacitance = charge stored/voltage applied

Constant of proportionality is “C”, the capacitance

C = Q/V

The ratio of the positive or negative charge Q on each conductor to the voltage v between them.

There are three ways to increase the capacitance of a capacitor

1. Increase the size of the plates 

2. Move the plates close together

3. Make the dielectric as good an insulator as possible

Symbols of Capacitor: Below are the capacitor symbols which are use in circuit.

Types of Capacitor:

  • Ceramic capacitors – Used in many applications from audio to RF , Values range from a few pico-farads to around 0.1 microfarads  & Widely used both in leaded and surface mount formats
  • Electrolytic capacitor –  A type of capacitor that is polarized , High capacitance values- typically above 1uF & it’s used for low frequency applications –  Power supplies, decoupling and audio coupling applications
  • Tantalum capacitor – Tantalum capacitors are polarized and offer a very high capacitance level for their volume. It consists of a pellet of tantalum metal as anode. Intolerant of being reverse biased. Reverse voltage can destroy the capacitor & it’s Available in both leaded and surface mount formats
  • Silver Mica Capacitor –  High levels of stability, low loss accuracy& it’s used for RF applications and limited to maximum values of 1000 pF.
  • Polystyrene Film Capacitor – They do not tolerate a high tolerance have a tolerance of 5% or 10%
  • Metalized Polyester Film Capacitor
  • Polycarbonate capacitor
  • Polypropylene capacitor
  • Glass capacitors
  • Super capacitor

Units and Formula of Capacitor – Capacitor is measured in units called farads (F)

Capacitor Charge Formula.

Q = C * V

Q = 100UF * 12V = 1.2 * 10 = 1.2 mC

mC is milli columbs

Current – Voltage (I-V) Relationships

   i = C dv/dt


There are four main capacitor applications

1. Coupling

2. Decoupling

3. Smoothing

4. Filtering- Capacitors are combined with resistors and inductors to create filters that only transmit signals of a particular frequency.

Capacitors Uses and Applications

1. Power supply smoothing applications

2. Audio frequency coupling uses

3. RF coupling capacitor applications

4. RF decoupling applications.

5. Turned circuit uses

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