Mica capacitors:

You might have seen mica, a naturally occurring, transparent substance which flakes off in thin sheets. This material makes a perfect dielectric for the capacitors.

Mica capacitors can be made by stacking metal sheets alternately and layers of mica, or by applying the silver ink to sheets of mica. The metal sheets are wired together into 2 meshed sets, forming the 2 terminals of the capacitor. This scheme is shown in the Figure given below.

Figure--Meshing of plates to increase capacitance.

Mica capacitors have low loss; which means that, they waste little power as heat, given that their voltage rating is not exceeded. The ratings of voltage can be up to several thousand volts if the thick sheets of mica are taken in use. But mica capacitors tend to be physically in proportion to their capacitance. The basic application for the mica capacitors is in radio receivers and transmitters. Their capacitances are a lower than those of paper capacitors, which are ranging from a few tens of picofarads up to around 0.05 µF.