Standard Test Method for Dissipation Factor and Permittivity (Dielectric Constant) of Mica

The dissipation factor of natural muscovite mica, as determined by this test method, is of practical importance as a measure of the electrical energy lost as heat in the mica serving as the dielectric substance of capacitors, or in other applications in which the electric field is applied perpendicular to the plane of cleavage. The dissipation factor is particularly important in applications using mica at radio frequencies and in some less extensive audio frequency applications. This test method is suitable for specification acceptance and dielectric-loss control tests (See the Significance and Use of Test Methods D 150).

Relative Permittivity (Dielectric Constant)—The permittivity of natural muscovite mica is a measure of its relative ability to store electrostatic energy. Since the relative permittivity perpendicular to the cleavage plane is fairly uniform, regardless of origin, its practical significance is mainly for identification purposes, special uses, research, and design. If a loss index is desired, the value of the permittivity must be known (see the Significance and Use of Test Methods D 150).