Mica capacitors are high cost, which together with their large physical dimensions reduces their usage. They have a relatively small capacitance that is under 100 nanofarads (nF), a typical order of value is 100 picofarads (pF). The maximum operating voltage of mica capacitors is high, with maximum values of 1 kilovolt (kV). A typical value is 500 volts (V). The advantage of mica capacitors is their high precision, meaning that produced capacitance value is very close to the nominal value (within the margin of ±1 %).

Mica capacitors implement a basic three-layer capacitor structure, conductor-dielectric-conductor, in the form of the following: metal-mica-metal. Only silver mica capacitors are currently used (the other type, clamped mica capacitor, is obsolete). Silver mica capacitors have silver electrodes plated directly onto the mica dielectric. They are not polarized so they may be connected to either positive or negative voltage.

Mica is a natural mineral with good mechanical, electrical and chemical properties that enable mica capacitors to be stable, reliable and to have low loss (i.e. to dissipate low heat level).

Applications of mica capacitors include radio because mica capacitor properties do not degrade as radio frequency increases. For example, mica capacitors are used in radio transmitters.