GB278400A - Improvements in radio receiving systems - Google Patents

Abstract

278,400. Leich, O. M. May 11, 1926. Thermionic amplifiers and detectors; receiving sets, construction of. - In order to prevent undesirable interaction between the input and output circuits of a multivalve receiver, either through interelectrode capacity inside the valves, or through external coupling between adjacent coils, metal strips 86 or 92, Fig. 1, are mounted in close proximity to the secondary windings 32 or 41 of the intervalve transformers, and are connected back to the grid of the previous valve so as to form a capacity link for the transfer of balancing voltages. In an alternative circuit, the metal capacity strips are applied to both input and ouput coils, and are merely connected together by a conducting lead. In a further modification, shown in Fig. 8, capacity strips 155, 158 are mounted close to open-ended coils 153, 157, coupled to input coils 106, 126. The coils 153, 157, forming one plate of each balancing condenser, are connected directly to output coils 120, 132, whilst the metal strips 155, 158, forming the coacting plates of the balancing, condenser, are connected directly to the filament or earth circuit. Plugs 51 and 21, Fig. 1, enable the number of valves in circuit to be changed. The intervalve transformers are set at an angle as shown in Fig. 3, and each capacity strip 86 is adjustably mounted by the side of the coil windings on screw studs 87.