# Capacitor electric capacitance: essence and main characteristics

Both in industry and in everyday life, it is often necessary to create a large number of positive and negative electrical charges. It is clear that by electrifying bodies and electrostatic induction this can not be done. It turns out that you need a special device. Such a device is a capacitor.

The capacitor is an uncomplicated system consisting of a dielectric separating the two plates. It is very important that the thickness of this dielectric is small in comparison with the dimensions of these same plates, that is, conductors.

The simplest kind of electrical capacitive devices is a flat capacitor, which is a complex of two metal plates separated by some kind of dielectric. If an electric current is applied to these plates, then the quantitative value of the strength of the electric field that arises between them will be almost twice as large as the same intensity for one of these plates.

The most important indicator characterizing this system is the electric capacity. The capacitance of the capacitor in terms of the basis of electromechanics is equal to the ratio of the charge of one of the applied plates to the voltage between the conductors of this device. In general, the capacitance of the capacitor will look like this:

C = q / U

If the position of the plates in space remains unchanged for a long time, the capacitance of the capacitor remains constant (regardless of the quantitative parameters of the charge on the plates).

In the International System of Physical Measurements, the capacitance of the capacitor is measured in Farad (F). According to this classification, one farad characterizes the electrical capacity of such a device, in which the voltage between dielectrics is one volt, and the amount of charge that is supplied to the plates is equal to one pendant.

The electrical capacitance of a flat capacitor will depend directly on the area of its plates and will increase when the distance between them decreases. To significantly increase the electrical capacitance of these devices, conductors are introduced with various dielectrics.

Most often, the electrodes for capacitors are made of thin foil, and the main liner is paper, mica or ceramics. It is in accordance with the material that serves as the basis for dielectrics that capacitors get their names - paper, ceramic, air, mica. Quite a large spread recently received electrolytic capacitors, which for sufficiently compact dimensions have a significant electrical capacity. Due to these qualities, they are actively used in household appliances, as well as as rectifiers of electric current.

Condensers are one of the most indispensable electrical devices, without which it would simply be impossible to create most household and electrical appliances.