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Monday, December 22, 2014

MICA CAPACITORS

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.