GB514686A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

514,686. Thermionic valves. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. April 28, 1938, No. 12661. Convention date, April 28, 1937. [Class 39 (i)] In a mixer valve imperforate, positivelybiassed electrodes are placed between the signal control grid and the oscillator control grid, these electrodes receiving electrons from the main stream or streams which may be repelled when the oscillator grid swings negative ; this prevents signal control grid current. As shown in Fig. 1, between the first control grid 11 and the second control grid 13 and in line with the support rods is disposed a pair of auxiliary electrodes 17, at a higher positive potential than the intermediate screen grid 12. An outer screen grid 14 and a suppressor grid 16 are disposed between the control grid 13 and anode 15. In a modification, the auxiliary electrodes may comprise channel-shaped members 42 enclosing the ends of and electrically connected to the screen grid 37. The cathode 35 is rectangular with emissive material only on the sides from which the electron streams depart. The wires of the control grid 36 are parallel to these faces. The valve may have a metal envelope. In a further modification, the second control grid has two additional support rods 45 opposite the coated faces of the cathode; these assist in the repulsion of the electrons towards members 42. Specification 439,082 and U.S.A. Specification 1,896,780, are referred to. Reference has been directed by the Comptroller to Specification 471,411.