GB617332A - Electron discharge devices and associated resonator circuits for use at high-frequencies - Google Patents

Abstract

617,332. Electric resonators. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 30, 1945, No. 19394. Convention date, Dec. 31, 1943. [Class 40 (viii)] [Also in Group XL (a)] An electron discharge device has an anode 13, Fig. 1, grid 12 and cathode 10, all in the form of inverted cylindrical cups, the anode 13 forms part of the envelope, the grid 12 is connected to a flange 25 sealed through an insulating part of the envelope and is attached to an apertured disc 43, and grid-cathode and grid-anode resonators are arranged on either side of the disc 43, at least the grid-cathode resonator being a coaxial line resonator. - The grid - anode resonator may be an open-ended half-wave coaxial line, as shown; the open end may be closed provided the outer conductor extends beyond the end of the inner conductor. The grid-cathode resonator is tuned by a variable condenser 51, 62, the member 62 being movable by suitable worm gearing. The inner conductor of the grid-cathode resonator contacts an extension 31 of a cathode supporting tube 19 through spring fingers 52. Members 56, 31, 19 form one cathode lead, and member 22, pin 34 and socket 53, and member 55 form the other cathode lead. The indirectly heated cathode is supported on the tube 19 by fingers 20 which reduce heat flow. The grid is supported on conical member 15 and a rod 11<1> with a cap 29 renders the cathode-grid structure rigid. The anode has cooling fins 14, and a slot 59<1> in member 59 provides an inlet for cooling fluid. Anode potential is supplied by a conductor 82 extending along a radio-frequency nodal line, the point 48 of which is spring-biassed into contact with the anode. Sliding clamps 45 are used to secure the grid flange 25 to the disc 43. The device acts as an oscillator, the two resonators being coupled by loops 72, 73, the loop 72 being telescopically adjustable and the reactance of the coupling loops being variable by a stub 74, 75 with movable tuning piston 76. Output is taken off at 57, 58. 26 is a getter. Anode potential may be direct or in the form of pulses. In a modified arrangement, Fig. 7, the valve construction is the same as in Fig. 1. The grid-anode resonator is, however, in the form of a hollow drum 92 and incorporates a condenser 93, 94 with dielectric 91, which may be mica discs having graded annular rings of silver and coated with titanium oxide salve; fillets of this salve are also placed around the edges of the electrodes 93, 94. The grid-cathode resonator is tuned by piston 621. A feedback line 97 screened by member 99 is connected to the conductor 41<1> by movable member 98. The anode is cooled by air directed on to fins 14, the glass ring 18 and metal to glass seals by four jets of air introduced at 100, and the cathode to grid glasswork by an air jet inside the cover 99.