GB946730A - Improvements in or relating to electrical capacitors - Google Patents

Abstract

946,730. Capacitors. SIEMENS & HALSKE A.G. June 22, 1962 [June 23, 1961], No. 24079/62. Heading H1M. An electrical capacitor comprises a pair of electrodes separated by a single dielectric layer; one electrode comprising two electrically interconnected metal coatings of which one is deposited on a first varnish layer situated in the field free space between the two coatings and the dielectric layer comprises a second varnish layer overlying the metal coating which is deposited on the first varnish layer. Fig. 1 shows a self-healing capacitor wherein an e.g. cellulose acetate varnish layer 1 formed by painting on a carrier (not shown) is coated with an e.g. aluminium metallic layer 3 by vaporization, which is coated with an e.g. polystyrene varnish layer 5. Two such triple foils are superimposed in assembly 11 with similar varnish layers 1, 2 in contact and lying in the field free region between the metallic layers 3, 4 which are interconnected to a single electrode, e.g. by spraying a metallic zinc end contact and the opposed electrode is formed by metallic layers 9, 10 on varnish layers 7, 8, which are superimposed to lie in the field free region of the metallic layers, interconnected as before. The pairs of metallic layers may be staggered. In a modification (Fig. 2, not shown) each electrode comprises a triple film of e.g. polystyrene, aluminium, cellulose acetate superimposed on a double foil of e.g. aluminium and polystyrene; the aluminium layers being interconnected as before. In a further modification (Fig. 3, not shown) the first electrode comprises two superimposed triple films of polystyrene, aluminium, cellulose acetate with the aluminium layers interconnected, and the second electrode comprises a simple metallic foil superimposed thereon.