A mica capacitor has dielectrics of thin rectangular sheets of mica, a natural mineral. Mica has a dielectric constant from 6 to 8. The electrodes are either thin sheets of metal foil interleaved between mica sheets, or thin films of silver that have been screened and fired on the mica. Silvered mica capacitors (ซิลเวอร์ไมก้าคาปาซิเตอร์ เหมาะที่จะใช้กับวงจรความถี่สูง) have greater mechanical stability and offer more uniform properties than foil and mica capacitors. Both are used primarily in RF applications. Mica capacitors perform satisfactorily over temperature ranges as wide as −55 to 150°C, and they have high insulation resistance. Their capacitance values range from about 1 pF to 0.1 μF. However, they have a low ratio of capacitance to volume or mass.
