Ottawa Mica Capacitors

What is a mica capacitor?

Definition – A mica capacitor uses mica as the internal dielectric. Mica capacitors come in two different types: clamped and silver mica capacitors. They are extremely stable components and have low resistive and inductive losses. Mica capacitors are created by layering mica sheets that have been coated with metal on either side.

Can mica capacitors withstand high voltages?

Mica capacitors can withstand high voltages, operate at high temperatures and have low leakage current. Because mica capacitors have a very small inductive characteristic and low losses, they are often used in radio frequency (RF) circuits. Silver is used to form mica capacitor plates.

What are silver mica capacitors used for?

Silver mica capacitors are used in high-frequency RF tuned circuits such as those found in filters, oscillators and power amplifiers. In filters, the tolerances and low losses (high Qs) of silver mica capacitors result in precise and predictable tuned-circuit performance.

What is a good replacement for silver mica capacitors?

In low power RF applications, a good replacement for silver mica capacitors is ceramic capacitors. If small capacitance tolerances, low losses and a low temperature coefficient are needed, Class I ceramic capacitors can be used. These ceramic capacitors have characteristics like silver mica capacitors, but at a fraction of the price.

What metal is used to make mica capacitors?

Silver is used to form mica capacitor plates. Other metals, like copper and aluminum, have been used, but do not perform as well. Silver mica capacitors offer tight tolerances from ±0.05% to ±5%. It is difficult to manufacture silver mica capacitors with large capacitance values, and they run from 0.5 pF to a few nanofarads.

Are silver mica capacitors worth it?

Silver mica capacitors are worth their high price for RF circuits. Find out how they work and when you can use a cheaper alternative. Use Up/Down Arrow keys to increase or decrease volume. This article is part of The engineer’s complete guide to capacitors.