If we go to the dictionary of the Royal Spanish Academy (RAE ) in search of the term capacitor , we will not find it. The concept, which derives from the English language, is used to refer to a electric capacitor .
It is a system composed of two drivers : materials capable of conducting the electricity (the force caused by rejection and the attraction of charged particles). In the case of capacitors, the drivers are separated from each other by a sheet which is used for the storage of electric charges .
A capacitor is a passive component since it does not take care of the electrical excitation, but it serves to connect active components and conserve energy. This allows you to support a electric field .
It is important to mention that the conductors are separated by a material dielectric (which has low driving capacity). Given the difference of potential , the conductors in question have different electric charges (negative in one and positive in the other), with a zero variation in the total charge.
There are various types of dielectrics, depending on the capacitor and its applications. In the case of air capacitors , which are usually parallel plates in a glass capsule, dielectrics of air . The capacity values allowed by this type of capacitor are very small, and its applications are radar and radio because of no polarization or losses in the dielectric, so it can work properly at high frequencies.
Mica is another of the materials used as a capacitor dielectric, thanks to several of its characteristics, such as the possibility of cutting into thin sheets, a low level of losses, great resistance to humidity, oxidation and high temperatures. In the mica capacitors a sheet of this material is placed and on it, aluminum; then many of them are stacked and their ends are welded to the terminals. Although its performance is exceptional at high frequencies and can withstand high voltages, its price leads consumers to opt for cheaper alternatives.
Other capacitors use paper undergoing some treatment that increases the isolation and reduce hygroscopy for the dielectric, such as bakelized paper and paraffin paper. A pair of paper tapes, one of aluminum and, finally, two more of paper must be stacked; everything is rolled in a spiral and, ready.
The self-regenerating capacitors they also use paper, and its application is found in industrial environments. If an overload occurs that exceeds the dielectric strength, the paper cracks and this causes a short circuit between the aluminum sheets.
On the other hand are the electrolytic capacitors , that as the first armor they use a electrolyte . If an adequate amount of tension is applied, it provides an insulating layer, usually of aluminum oxide and of a very small thickness, on a second reinforcement, which allows to reach very high capacities.
The capacitors, in reality, do not store the current not even the electric charge: what they store is latent mechanical energy . When they are introduced in a electrical circuit , in particular they do work as a device that preserves the electric power obtained in the charging period, after which said energy is transferred by the capacitor.
It is called capacitance to electrical capacity; that is, to the property of an element to conserve an electric charge. In the case of capacitors, the capacitance is equivalent to the level of electrical energy that it conserves according to the existing difference in the electrical potential.