Correctly to calculate parameters of condensers in the course of their development and production, it is necessary to know such parameter as dielectric permeability.
Instruction
1. The dielectric permeability ε (relative) environments is a physical quantity which characterizes properties of the dielectric (isolating) environment. It is connected with effect of polarization of dielectrics under the influence of electric field. Dielectric проницаемостьε shows how much there is less than force of interaction of electric charges in any environment, than in a vacuum.
2. To define dielectric permeability of substance εr, compare the capacity of the condenser taken as test, with the set dielectric (Cx) and the capacity of the same condenser, but in a vacuum (Co): Ɛr = Cx/Co
3. The dielectric permeability of the majority of gases, including air, in usual conditions approaches unit (because of their low density). The most part of solid dielectrics relative has dielectric permeability which lies in the range from 2 to 8. In the static field the dielectric constant of water has rather high value — about 80.
4. Substances with molecules which possess a considerable electric dipole are also of great importance of dielectric permeability. For example, the dielectric permeability of a ferroelectric material is estimated in tens and hundreds of thousands.
5. The dielectric permeability is one of the major parameters during creation of condensers. Use of materials which have high dielectric permeability allows to reduce the geometrical sizes of condensers considerably.
6. Capacity of electric condensers is determined by a formula: C = Ɛr*Ɛo*S/dГде: εr — dielectric permeability of the insulator between facings, εо — an electric constant, S — the surface area of facings of the condenser, d — an interval between facings. The dielectric permeability is taken into consideration also during creation of printed circuit boards.