
What are Capacitors? Types of capacitors?
The capacitor's function is to
store electricity, or electrical energy.
The capacitor also functions as a filter, passing alternating current (AC), and
blocking direct current (DC).
This symbol
is used to
indicate a capacitor in a circuit diagram.
Capacitors are occasionally referred to as condensers.

The capacitor's capacitance (C)
is a measure of the amount of charge (Q) stored on each plate for a given
potential difference or voltage (V) which appears between the
plates:
C=Q/V

A capacitor is a passive
electronic component that stores energy in the form of an electrostatic field.
In its simplest form, a capacitor consists of two conducting plates separated by
an insulating material called the dielectric. The capacitance is directly
proportional to the surface areas of the plates, and is inversely proportional
to the separation between the plates. Capacitance also depends on the dielectric
constant of the substance separating the plates.
Capacitor Types
1) Capacitors can be used to
control timing, filtering, and smoothing out power supplies.
2) Three major types of
capacitors are ceramic, electrolytic, and tantalum
3) Ceramic capacitors are
small in size and value, ranging from a few Pico Farads to 1 µF. Not polarized,
so either end can go to ground. Value is given by a mystical code somewhat like
that of resistors.
4) Electrolytic capacitors
look like small cylinders and range in value from 1 µF to several Farads. Very
inaccurate and change in value as the electrolytic ages. Polarized, cathode must
go to ground. Cathode is marked with a minus sign on case. Value is usually
written on case.
5) Tantalum capacitors are
similar in size to ceramic but can hold more charge, up to several hundred µF.
Accurate and stable, but relatively expensive. Usually Polarized, anode is
marked with a plus sign.