Mica is popularly known as Isin glass. Important
characteristics of Mica:
i) Its ability to operate at very high temperature (upto 500
oC).
ii) The material is almost totally inert and will not change
with age, either chemically or physically.
iii) Mica is usable as a dielectric in its naturally state.
iv) It can be readily split into very thin sheets.
Mica capacitors are made by a method of depositing a thin
layer of silver on each side of sheet of Mica was developed. This is done by a
type of silver screen process. The silver is then fired in a furnace.
The principal advantage of Mica capacitor is its excellent
degree of stability over a wide range of operating temperatures.
Mica capacitors are also among the best types to use where
radio frequencies are involved.
Disadvantages of Mica capacitors:
i) They are relatively bulky when compared to other
capacitors on a pure capacitance vs volume basis.
ii) The flat plates and method of construction lead to
resonant frequency problems in some circuits.
