GB473498A - Improvements in and relating to thermionic valves - Google Patents

Abstract

473,498. Thermionic valves. TELEPHONE MANUFACTURING CO., Ltd., and PADDLE, L. H. June 30, 1936, Nos. 18118 and 24127. [Class 39 (i)] A short-wave or ultra-short wave generator comprises a unitary structure having at least two electrically independent cathodes, at least two anodes and a control grid common to both anode-cathode streams, or two control grids and a common anode, and an inductance connected between the two grids or the two anodes. The generator is of the type described in Specification 450,967. The capacity between the cathodes should be low and the cathodes may be indirectly-heated by electrically independent heaters. Two, four or more structures may be combined within one envelope, e.g. four structures may be so arranged and each pair of grids may be connected together by a member as far as possible devoid of inductance. A valve may comprise two hairpin or W-shaped filaments mounted upon axial re-entrant stems of a cylindrical envelope. A continuous control grid or two control grids of wound form and connected together surround the cathodes. Two separate cylindrical or box anodes surround the grids. In another form two parallel cathodes are enclosed, one in each loop, of a grid in the form of a figure of eight. The common grids or anodes may consist of separate grids or anodes connected together so as to be incapable of relative potential variation. The anodes consist of wire, sheet mesh or of wound grids.