Silver mica capacitor

Silver mica capacitors are high precision high stability high reliability capacitors. They are available in small values, and are mostly used at high frequencies.

Types

Mica capacitors, which are now obsolete, were in use in the early 20th century. They consisted of sheets of mica and copper foil sandwiched together and clamped.

Silver mica capacitors, also known as silvered mica capacitors, obsoleted mica capacitors. Instead of being clamped with foils these use sheets of mica coated on both sides with deposited metal. The assembly is dipped in epoxy. The advantages are:
* greater stability, since there are no capacitive airgaps that can change dimension,
* airtight enclosure removes the risk of oxidation or corrosion of plates or connections.
* greater value per volume, since
** there are no airgaps between plates and mica,
** the conducting surfaces can be thinner.
** no clamping mechanism is needed

Silver mica capacitors are one of the less popularly used types because of price. Example prices:
* 100pF £0:99
* 10nF 1% silver mica £4:40

[ [http://www.rapidonline.com/productinfo.aspx?kw=silvered%20mica&tier1=Electronic+Components&tier2=Capacitors&tier3=Mica&tier4=Silvered+mica+capacitors&moduleno=62503 Rapid Electronics - Silvered mica capacitors ] ]

ee also

Capacitor

References