The capacitor is an electronic device,which allows you to accumulate and then give an electric discharge. The main characteristic of the element is its capacitance, which determines the dependence of the charge on the voltage.
Classification of capacitors
Various technologies for the release of devices allowproduce different types of instruments. Airconductors include products in which the dielectric is air. Advantages of this type of device are the ease of manufacture. They are intended for mechanical capacity control and are designed for mechanical permanent effects. The disadvantages of this type of device include instability, poor reliability, dependence on humidity and temperature of the medium, large dimensions, relatively low electrical strength, which is limited by breakdown between the platinum of air, as well as low capacity.
There are paper types of capacitors in whichthe paper impregnated with transformer oil acts as a dielectric. These devices have high reliability and electrical strength. At high voltage they have a sufficiently high capacity and low current leakage.
Many capacitors for power plantsproduce by paper principle. For this, two plates are folded together, between which paper is placed. The device is then rolled up and placed in a jar filled with transformer oil and then sealed. The disadvantages of the device include a large weight, high own inductance and resistance.
Electrolytic types of capacitors havedielectric, represented in the form of an oxide layer that appears on the surface of the active metal (more often aluminum). The device is produced by placing in a electrolyte a tape made of active metal, on the surface of which a film of strong oxide is formed, which makes it possible to isolate the metal.
The main feature of electrolytic speciescapacitors is the presence of polarity, with one value of which they hold the calculated voltage, and when it changes quickly they are destroyed. This occurs as a result of chemical processes occurring between the electrolyte and the metal of the plate. The oxide film gradually cracks and breaks down.
However, if the correct polarity is observedMicrocracks are quickly tightened with a new oxide. The advantages of these devices include high capacity, disadvantages - polarity, loss of properties, rapid wear, high internal inductance.
Types of capacitors and their application
There are also devices in whichdielectric is mica, they are used in various electrical installations. Since mica is able to independently accumulate energy, these types of capacitors have high capacitance and electrical strength. The disadvantages include instability of parameters, nonlinearity, high price and dependence of capacitance on current strength.
In addition, ceramic types of capacitors, film, teflon, polypropylene and other devices have been used.