2. INTRODUCTION TO
CAPACITOR
Capacitor was invented by Ewald Georg Von Kleist
Capacitor is a passive two terminal electrical component
that stores potential energy in an electric field.
The effect of capacitor is known as capacitence.
While some capacitance exists between any two electrical
conductors is proximity in a circuit.
Capacitor is designed to add capacitance to the circuit.
Capacitor was originally known as condenser or
compensator.
6. In October 1745 Ewald George Von Kleist of
Powerania,Germany found that charge could be stored by
connecting a high voltage.
Electrostatic Generator by a wire to a volume of water in a
hand held glass jar.
The water acted as conductors
And the jar as dielectric mechanism
8. A simple demonstration capacitor made of two parallel
metal plates, using an air gap as the dielectric.
9. A capacitor consists of two conductors separated by a non-
conductive region.
The non-conductive region can either be a vacuum or an electrical
insulator material known as a dielectric
Examples of dielectric media are:-
1. Glass
2. Air
3. Paper
4. Ceramic
10. CHARACTERISTICS OF
CAPACITOR
It blocks flow of DC and permits AC
It is used for coupling two devices
It bypasses the unwanted frequencies
It feeds the desired signal to any section
It is used for phase shifting, filtering, motor starter.
It is used to get tuned frequency.
14. Paper capacitors are made of paper or oil-impregnated paper and
aluminum foil layers rolled into a cylinder and sealed with wax.
These capacitors were commonly used but are now replaced by
the plastic or polymer type of capacitors.
The paper capacitors are bulky, highly hygroscopic and soaks
moisture which causes loss to the dielectric degrading its overall
performance is the major drawback with type of capacitors.
16. Ceramic capacitors are also known as disc capacitors,they are
generally made by coating two sides of a small porcelain or
ceramic disc with silver and then stacked together to make a
capacitor.
For very low capacitance values, a single ceramic disc of about 3-
6mm is used.
Ceramic capacitors have a high dielectric constant and are
available so that relatively high capacitances can be obtained in
a small physical size.
18. The mica capacitor uses mica as the dielectric medium.
Mica is inert in nature and hence the physical and chemical
properties do not change as it ages.
It provides good temperature stability and resistance to corona
discharge that is electrical discharges due to ionization around
conductor.
However, the cost is very high due to improper sealing the
capacitor is highly prone to moisture which increases the power
factor
21. These use polystyrene, polycarbonate or Teflon as their dielectrics
are sometimes called plastic capacitors.
The construction of plastic film capacitors is similar to that for
paper film capacitors but use a plastic film instead of paper
The main advantage of plastic film capacitors compared to
impregnated paper types is that they operate well under
conditions of high temperatures, have smaller tolerances, a very
long service life and high reliability
23. Electrolytic Capacitors are generally used when very large
capacitance values are required.
Here instead of using a very thin metallic film layer for one of
the electrodes a semi-liquid electrolyte solution in the form of a
jelly or paste is used which serves as the second electrode