GB410619A - Improvements in or relating to electron discharge devices and circuits incorporatingthe same - Google Patents

Abstract

410,619. Thermionic valves; valve circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Marconi House, Strand, London, and SHRADER, T. M., 40, Laurel Drive, West Summit, New Jersey, U.S.A. June 6, 1933, No. 16278. Convention date, July 12, 1932. [Classes 39 (i) and 40 (v).] A valve comprises within a single envelope a multi-electrode assembly, a plate, one or more grids, a cathode, a pair of anode electrodes adjacent a portion of the cathode so as to form with it a pair of diodes, and electrostatic means shielding the diode anodes from the multielectrode assembly. In one form, Fig. 1, a triode assembly comprises an indirectly-heated cathode 17 having a non- inductively wound heater, a grid 16 and an anode 15 spaced and supported by insulating plates 19, 20. The upper spacer 19 is preferably a cruciform sheet of mica. Metal clips 21 secure the wings of the anode 15 to the spacers. The cathode is extended below the spacer 20 and is surrounded by ring-shaped diode anodes 22 supported on leads 23. The cathode is oxide-coated only on its upper and lower portions, the middle being left free. A metal hood 26, mounted on stays 27 and steadied by the cathode lead 24, screens the anodes 22 from the triode assembly. Fig. 5 shows a circuit for use with the valve. The diodes 22 form with the cathode 17 a fullwave detector. The radio-frequency component is byepassed by a condenser 39. the audio-frequency is applied through lead 36 to the grid 16 of the triode and the unidirectional voltage supplies an automatic volume control stage through lead 40. In a modification, the grid 16 is given a fixed bias and is coupled to the centre-tap 35 through a condenser. In another form, Fig. 7, the diodes are coupled with separate circuits 48, 49. Circuit 48 comprises a condenser 39 byepassing the radio-frequency component and is coupled to the grid 16 by a condenser 46. Circuit 49 comprises a condenser 39 bye-passing both radio and audio-frequencies and supplies a unidirectional voltage through lead 40 to an automatic volume control stage.