And in industry and in everyday life often requires the creation of a large number of positive and negative electric charges.It is understood that by electrification and electrostatic induction phone is impossible.It turns out that you need a special device.Such a device is a capacitor.
capacitor is a simple system consisting of a dielectric separating the two plates.It is very important that the thickness of the dielectric was small compared to the size of these same electrodes, i.e. conductors.
simplest form of electrical devices is a capacitive plate capacitor, which is a complex of two metal plates separated by a dielectric.If these plates fail to electric current, the quantitative value of tension arising between the electric field is almost two times higher than the same tension in one of the plates.
most important indicator of this system is electrical capacitance.Electric capacity of the condenser in terms of electro bases equals the ratio of the charge from one plate to the voltage applied between the conductors of this device.In general, the electrical capacitance of the capacitor is as follows:
C = q / U
If the position of the plates in the space of a long time remain unchanged, the electrical capacitance of the capacitor remains constant (regardless of the quantitative charge on the plates).
in the international system of physical measurements of electrical capacitance of the capacitor is measured in farads (F).According to this classification, one farad characterizes the electrical capacitance of the device, in which the voltage between the dielectric is one volt, and the magnitude of the charge, which is served on a plate, is equal to one coulomb.
In fact, one farad - this is a very large value, so often used such units as microfarad nF and even PF.
Electric capacity flat capacitor will depend on the area of its plates and will increase with the reduction of the distance between them.To significantly increase the electrical capacity of the instrument is introduced between the conductors or another dielectric.
The most common electrodes for capacitors made from a thin foil, and as the primary lining using paper, mica or ceramic.It is in accordance with the material, which serves as a basis for dielectrics, capacitors and get their names - paper, ceramic, air, mica.Fairly widespread recently received Electrolytic capacitors are sufficiently compact dimensions have considerable electric capacity.Because of these qualities, they are widely used in home appliances, as well as electric current rectifiers.
capacitors are among the most essential electrical appliances, without which it would be simply impossible to create the majority of household and electrical appliances.
