These capacitors are made using vitreous enamel on mixture of silica, alkali oxides and fluorides as dielectrics. These capacitors are formed by spraying vitreous lacquer on metal plates which are stacked, and fired at a temperature high enough to vitrify the glaze capacitors made in this way have excellent r.f. characteristics of exceedingly low loss and can be operated at high temperature capacitors are made simultaneously and then cut to require sized. Then they are fired and leads are soldered.
Range of values 15pf to 5000pf
Power factor at 1 KHz 0.001 to 0.02
Voltage rating up to 500V
Temperature coefficient 105 ppm/0C