dielectric(redirected from Dielectric medium)
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Related to Dielectric medium: dielectric constant, polarization, permittivity
dielectric(dī'ĭlĕk`trĭk), material that does not conduct electricity readily, i.e., an insulator (see insulationinsulation
, use of materials or devices to inhibit or prevent the conduction of heat or of electricity. Common heat insulators are, fur, feathers, fiberglass, cellulose fibers, stone, wood, and wool; all are poor conductors of heat.
..... Click the link for more information. ). A good dielectric should also have other properties: It must resist breakdown under high voltages; it should not itself draw appreciable power from the circuit; it must have reasonable physical stability; and none of its characteristics should vary much over a fairly wide temperature range. One important application of dielectrics is as the material separating the plates of a capacitorcapacitor
device for the storage of electric charge. Simple capacitors consist of two plates made of an electrically conducting material (e.g., a metal) and separated by a nonconducting material or dielectric (e.g.
..... Click the link for more information. . A capacitor with plates of a given area will vary in its ability to store electric charge depending on the material separating the plates. On the basis of this variation each insulating material can be assigned a dielectric constant. Generally, the dielectric constant of air is defined as 1 and other dielectric constants are determined with reference to it. Other properties of interest in a dielectric are dielectric strength, a measure of the maximum voltage it can sustain without significant conduction, and the degree to which it is free from power losses.
1. a substance or medium that can sustain a static electric field within it
2. a substance or body of very low electrical conductivity; insulator