What electrical properties are measured for electrically insulating adhesives?
Dielectric constant (permittivity) and dissipation factor (loss tangent) are typical electrical properties that are reported for electrically insulating adhesives. The dielectric constant is a measure of a materials ability to store electrical charge. The dielectric constant is defined by a ratio of the capacitance induced when an electric field is applied between two separated metal plates with and without the insulator between them. The difference is due to polarization occurring in the dielectric. A low dielectric constant is generally desirable because it will result in higher signal propagation speed. A high dielectric constant will result in a much slower signal propagation speed. In the set up described above, when the electric field is time dependent (alternating current) the polarization occurring is also time dependent. Resistance by the atoms in the dielectric delays changes in the electric field and polarization. This translates to absorbed energy in the form of heat. The d
