GB295343A - Improvements relating to thermionic valves or electron discharge tubes - Google Patents

Abstract

295,343. Mullard, S. R., (Naamlooze Vennootschap Philips' Gloeilampenfabrieken). May 7, 1927. Vacuum tubes. - Thermionic valves passing current in one direction only contain in a single evacuated envelope two or more separate sets of grids 3 and anodes 4 disposed along the length of a single long, straight cathode 9 indirectly heated by a separate heater. The cathode 9 may comprise a metal cylinder coated with barium oxide and containing a straight or looped filament heater 10. To prevent. interaction, the electrode sets may be screened by metal discs 11, 12 projecting radially from, and at the potential of, the cathode cylinder. Leads to the electrodes are led through a single pinch 2 and through apertures in the discs 11, 12, or leads to the top set of electrodes may be led through the upper end of the bulb 1. The electrode sets mav be used as different stages in a radio receiver or the anode of one set may be connected to the grid of the next. The filament 10 mav emit electrons and may be used together with the cathode 9 as a rectifier in the anode voltage supply.