GB374889A - Improvements in or relating to electric discharge devices - Google Patents

Abstract

374,889. Discharge apparatus. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE, 12, Hallesches Ufer, Berlin. March 9, 1931, No. 7299. Convention date, March 7, 1930. [Class 39 (i).] An electric discharge device adapted more particularly for amplifying purposes, wherein the electron source is constituted by a glow discharge maintained in a rarefied gas, comprises a hollow cathode co-operating with an anode to set up a glow discharge substantially axially within the cathode, a main or amplifying anode situated farther from the cathode than the discharge anode, and a control electrode positioned and arranged to control the electronic stream passing from the axial discharge through or round the discharge anode to the main anode. In one form the hollow cathode 8, Fig. 1, is surrounded by an insulating casing 6 of glass, porcelain, or like material, having a reduced lower part 7 which is pushed over a small glass tube fused to the pinch 2. The discharge anode 9 is in the form of a cap fitting over the insulating casing 6 and provided with perforations for the passage of the electron stream, a current lead 3 being connected thereto. The main or amplifying anode 5 towards which the electron stream is drawn comprises a cylindrical metal cap upon the lower part of the insulating casing 6, the passage of the electrons being controlled by the external electrode 10. A filling of a rare gas, or a mixture of rare gases is provided. In another form with a cylindrical hollow cathode 8, Fig. 2, the gas pressure and the width of the discharge vessel are such that the cathode glow tends to form only on the inner side of the cathode wall, so that an insulator around the exterior, although preferable, may be dispensed with. The discharge anode 9 is in the form of a plate which screens the main anode 5 from the electrons emerging from the mouth of the cathode. The main anode 5 comprises a plate or long strip connected to a current lead which is surrounded by an insulating sleeve 12. A glass bridge 13 is preferably provided to maintain the electrode supports and leading-in wires in their correct relative positions.