GB431061A - Improvements in or relating to thermionic valves - Google Patents

Abstract

431,061. Thermionic valves. WARREN, S. F., 27, Lowick Road, Harrow, Middlesex. Dec. 29, 1933, No. 36635. [Class 39 (i)] A valve has a cathode 3, a control grid 4, a screening grid 5, an anode 6, an external screening grid 7 connected with the inner screening grid 5, which does not extend appreciably beyond the control grid and anode, and one or more end screening members 9, which are insulated from the screening grid: and are adapted tc screen lines of force which would otherwise extend beyond the control grid and anode around one or both ends of the inner screening grid. The end member 9 consists of a metal disc secured by clips to a mica disc 8 ; it is of smaller diameter than the external screening grid and has a central aperture allowing clearance for the support wires of the screening grid 5. The member 9 is connected with a point preferably of low potential such as the cathode or earth, and the connection may be made within the valve. At the lower end of the electrodes a tubular member 11 supports a mica disc spacing the electrodes 3, 4, 5 and is connected by one or more wires 13 with the member 9 and the cathode. The member 11 may be replaced by a disc similar to 9 but provided with an aperture through which the anode lead passes. The lead to the control grid is taken to a terminal on the top of the envelope. A suppressor grid may be mounted between the screening grid and the anode. Specifications 230,011, 280,851, 292,563, [all in Class 39 (i)], and 377,692 are referred to.