GB442465A - Improvements in or relating to electrical oscillation generator arrangements - Google Patents

Abstract

442,465. Thermionic valves and valve generating circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Electra House, Victoria Embankment, London.- (Assignees of Linder, E. G. ; 306, Cooper Street, Camden, New Jersey, U.S.A.) Dec. 21, 1934, No. 36662. Convention date, Dec. 21, 1933. [Classes 39 (i) and 40 (v)] An electronic-period oscillator of the magnetron or Barkhausen-Kurz types is provided with means for setting up an electrostatic field with a component in the direction of the axis of the electrodes. As shown in Figs. 1 and 3, a magnetron oscillator with a split cylindrical anode 7 arranged round an axial cathode 13 is provided with end-plates 21, 23 held at a positive potential relatively to the cathode. The electrostatic field within the anode is thus given an axial component as indicated by the full curved lines of Fig. 3, and the periodic movement of the electrons follows the dotted lines 31. The tube is placed in a magnetic field set up by coils 19 which may have a non-axial component. The end-plates 21, 23 are supported by conducting leads 25, 27, which pass out through the press 3 of the tube, and the anode sections are connected to parallel wires 9, 11 which pass through the opposite end of the tube to form a Lecher wire output circuit. The wires are bridged within the tube by a cross rod 6 placed at a voltage node, and this rod has an arm 10 fused into a glass bead 12 into which is also fused a rod 8 carried by the press 3. The external circuit, Fig. 4, comprises a D.C. source connected between the cathode 13 and the mid-point of a di-pole aerial 35 energized by the Lecher wires 9, 11. The endplates 21, 23 are given an adjustable positive voltage by a slider 45 on a potentiometer 41 across the D.C. source. Modulation voltage may be applied by a transformer in the lead 43, Fig. 9 (not shown). The end-plates may be separated from the cathode by small quartz cylinders, Fig. 7 (not shown). The anode plates 61 may be flared at their ends as shown in Fig. 6, whilst the end-plates 63 may be of conical shape. In another form of magnetron oscillator, Fig. 5, two cylindrical anodes 47, 51 each surrounding its own axial cathode are provided in the same tube 45, and the endplates 55 serve jointly for both anodes. The end-plates may be arranged across the open ends of the anode of a triode valve operating as a Barkhausen-Kurz oscillator, Fig. 8 (not shown).