GB174149A - Improvements in and relating to electron discharge devices for use as valves or oscillators - Google Patents

Abstract

174,149. British Thomson - Houston Co., Ltd., (General Electric Co.). Oct. 13, 1920. Vacuum tubes. - A thermionic valve for generating oscillations has a cathode mounted between an anode and a control electrode, a tuned circuit being connected so as to impress on the control electrode a potential negative with respect to the cathode, and varying at the frequency of the tuned circuit. As shown in Fig. 5, a tuned circuit comprising a condenser 21 shunted by a resistance 22, and an inductance 20 and variable condenser 23 in parallel is connected between the control electrode 12 and the cathode 5, an inductance 17, loosely coupled with the inductance 20, and a battery 18 being connected between the cathode and the anode 10. By this means the potential of the electrode 12 varies between that of the cathode and a relatively high negative potential, and oscillations are produced in the anode-cathode circuit, which are transferred to a work circuit 26 by means of an inductance 27 closely coupled with the inductance 17. As shown in Fig. 1, a tungsten anode 10 is mounted inside a coiled cathode 5 which is surrounded by a cylindrical molydenum control electrode 12; or the positions of the anode and control electrode may be reversed. In a modification the anode consists of a copper or other metal tube soldered or welded to platinum collars sealed in the envelope, the anode being cooled by the passages of a fluid such as water. In another arrangement the anode and control electrode consist of plates mounted one on each side of a V-shaped cathode.