The capacitor is a passive component and it stores the electrical energy into an electrical field. The ability of a capacitor to store electric charges is known as capacitance. This means that a large capacitor will store a huge amount of charges.

A capacitor consists of two close conductors that are separated by a dielectric material. When those plates are connected to the power they gather together the electric charge. One plate accumulates the positive charge and another plate accumulates the negative charge.


The capacitance is the ratio of electric charge (Q) to the voltage (V).

C = Q/V


  • C: capacitance expressed in farad
  • Q: electric charge expressed in coulombs
  • V: voltage between the plates expressed in volts



Electrolytic Capacitor

Electrolyte capacitors are used when in the circuit we require the large capacitor with large value.

Electrolytic capacitors are capacitors that are polarized means that they have negative polarity and positive polarity to distinguish them you will see on their legs (short leg means negative polarity and long leg means positive polarity). While connecting to the power supply you have to respect polarity respectively, negative polarity of power supply to negative polarity of capacitor and positive polarity of power supply to positive polarity of capacitor respectively.

Electrolytic capacitors are used in DC power supply circuits for the reason of their large capacitance and how they reduce ripple voltage.

They are applied in coupling and decoupling and their main disadvantage is that they have small low voltage ratings because of the polarities.

Mica Capacitor

Mica capacitor is a combination of natural minerals and the silver mica capacitors that uses the dielectric. Mica capacitor has two types of mica capacitors that are clamped capacitors referred as absolute because it has inferior characteristics and silver mica capacitors are prepared by sandwiching mica sheet that is coated with metal on two sides to protect the environment.

Clamped mica capacitors are considered obsolete because of their inferior characteristic. The silver mica capacitors are prepared by sandwiching mica sheet coated with metal on both sides and this assembly is then encased in epoxy to protect the environment.

These capacitors have very low loss and are used at high frequencies and they are chemically, electrically, and mechanically stable. They are used for designing calls.

Paper Capacitor

The construction of paper capacitor is separated from the paper, or oiled paper and thin waxed to make a cylindrical shape and then enclosed in the plastic capsule. Paper capacitor has a capacitance range from 0.001 to 2micro farad and the voltage is up to higher 2000V.

Film Capacitor

The film capacitors are also capacitors and they use a thin plastic as the dielectric. The film capacitor is prepared extremely thin using the sophisticated film drawing process. If the film is manufactured, it may be metalized depending on the properties of a capacitor. To protect from the environmental factor, the electrodes are added and they are assembled.

There are different types of film capacitors available like polyester film, metalized film, polypropylene film, PTE film and polystyrene film. The core difference between these capacitors types is the material used as a dielectric and dielectric should be chosen properly according to their properties. The applications of the film capacitors are stability, low inductance, and low cost. Film capacitance is used in aerospace and military technology and other long stability applications.

Non-Polarized Capacitors

Ceramic Capacitor

Ceramic capacitors are non-polarity capacitors. When it is going to be connected in a circuit it is not necessary to look at polarity because all legs are the same; you can’t know whether there is a positive or negative polarity.


The capacitance of a capacitor change within a range of value is called a variable resistor. Two plates of a capacitor are movable while another plate is fixed.


Polarity capacitor non-polarity capacitor


●Coupling capacitors used allow only AC signals to pass from one side of a circuit to another but it blocks any DC static voltage. This capacitor is mostly used in connecting two stages together in an amplifier.

●Decoupling capacitor used in this application to block any AC signals that may be on a DC bias point, power rail, or other node that needs to be free of a particular varying signal.

●RF coupling and decoupling applications

●Smoothing capacitor applications

●Timing element application