GB779794A - An improved electric condenser - Google Patents

Abstract

779,794. Capacitors. MULLER, W. Feb. 4, 1955 [Feb. 5, 1954], No. 3457/55. Class 37. A stack-type capacitor comprises a plurality of silvered mica plates 1, each bearing separate silvered areas 2, 3 on opposite sides thereof and extending around the edges of the plate to form portions 21, 31 respectively, the plates being provided with recesses 7, 8 and the silvering extending around the edges within these recesses so that, upon assembly of the plates into a stack, a clamping wire may be arranged around the recesses 7, 8, as shown in Fig. 10, so as to hold the plates assembled together and provide good electrical contact to each plate individually. The individual plates are formed from a large sheet of mica 12, Fig. 6. Slits 13 are first punched in the plate 12 at positions corresponding to the edges 2<SP>11</SP>, 3<SP>11</SP> of the individual plates 1; also holes 14 corresponding in position to the recesses 7, 8 are punched in the sheet 12. Silvered coatings are then formed on both surfaces of the sheet, a stencil being used to obtain the pattern shown. The sheet is then punched along the broken line to form the individual sheets 1 which are then stacked together to form a capacitor as shown in Fig. 10. The outermost sheets of the capacitor are thicker than the other plates thereof and the coatings formed on their outer surfaces are smaller than the coatings 2, 3. The clamping member comprises a length of wire 17 which is split longitudinally into two portions 19, 20 for the greater part of its length, these portions being bent round the recesses 7, 8 to hold the capacitor plates together. A portion of the wire which has not been split may serve as a soldering tag. To give added strength the plates may also be soldered together during assembly. The stack is first impregnated with a flux and liquid solder is then applied to the edges of the assembly so that it creeps by capillary action over the silvered areas of the plates, soldering these areas together. It is stated that the solder does not however extend over the unsilvered areas of the mica. The finished stacked assembly may be provided with a thin protective coating of lacquer.