In this tutorial we are going to learn below of capacitor.
1. Why and how to use
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
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