GB915142A - Electrical capacitor - Google Patents

Abstract

915,142. Capacitors. PACKARD-BELL ELECTRONICS CORPORATION. Dec. 14, 1960 [Dec. 14, 1959; Feb. 11, 1960], No. 43056/60. Class 37. A capacitor comprises a saucer-shaped metal electrode 11, a dielectric layer 12, e.g. of barium titanate, deposited on the electrode, and a silver layer 18 on the dielectric to form the second electrode. One terminal 14 is formed in one with electrode 11 and the other is soldered to layer 18. In another embodiment (Fig. 4, not shown) the dielectric layer covers the whole of the metal electrode. A multiple capacitor having two silver layers 48, 58 each acting as an electrode, is shown in Fig. 5, and a further multiple capacitor consisting of a metal electrode 73, dielectric layers 72, 75 and two further electrode layers 76, 78 in Fig. 6. The disc 11 may be of a monel metal alloy or stainless steel and is first tumbled in powdered ceramic, e.g. also barium titanate at a temperature less than the ceramic firing temperature (e.g. 1800� F.) to remove impurities from the metal which could contaminate the ceramic layer, which is subsequently sprayed and fired on at a temperature of about 2000 � F. The disc metal and ceramic material preferably have the same thermal coefficient of expansion, e.g. 1.6 x 10<SP>-5</SP>/<SP>�</SP> C. The silver layer is screened on to the ceramic and fired at about 1000� F. The thicknesses of the metal disc, ceramic, and metal film are stated to be less than 0.050 inch, 0.005 inch and 0.001 inch respectively. The capacitor terminals can be inserted into contacts in apertures in a printed circuit board (Fig. 3, not shown).