GB590463A - Improvements in electron discharge devices - Google Patents

Abstract

590,463. Electron beam apparatus ; wave guides. WESTERN ELECTRIC CO., Inc. March 14, 1944, No. 4772. Convention date, Aug. 29, 1942. [Classes 39 (i) and 40 (v)] An electric discharge device for use as a switch or pulse generator comprises a cathode 15, Fig. 1, a grid 17 and a cylindrical series of field electrodes 18 concentric with the cathode and grid. A rotating electric field is established between the cathode and electrodes 18 by energizing the latter from a multi-phase supply, or by a single phase source in conjunction with a split phase device, and the biassing potentials applied to the electrodes are such that the grid is a few volts positive to the cathode, and about 1/5 of the peak voltage of the electrodes 18 positive thereto. A rotating beam is thereby formed, and a slot 21 is provided in one or more of the electrodes 18 behind which is placed a collecting electrode 23 from which the output is taken, the frequency of which is determined by the number of slots and the speed of rotation of the beam. The grid has two skew supports 16 and the cathode may be indirectly heated or a thoriated tungsten filament, As applied to the sending distributer of a multi-plex telephone system, the arrangement comprises a cylindrical anode 32, Fig. 4, a number of field electrodes 118a-f, each with two slots 121, and with lip portions 30 overlapping the space between adjacent electrodes. Behind each slot is disposed a grid 31 to which the various signals are applied. The complex signal is applied to the grid 15 of the receiving distributer in. which the beam rotates synchronously with the sending instrument, and the appropriate signals are received on a series of collecting electrodes 33, Fig. 5 (not shown.). For frequency changing, the field electrodes are provided with the required number of slots relative to the frequency applied thereto and the output is taken from a single encircling collecting electrode, Figs. 6, 7 (not shown). Fig. 8 shows an oscillation generator. A cylindrical metallic wave guide 38 has an evacuated section bounded by a metallic plate 44 and a vitreous closure member 39. The cathode and grid are mounted on mica supports 41, 42. Two oscillating electric fields in quadrature are established in the evacuated space as described in Specification 420,447. During operation, the grid 16 is biassed at a relatively low positive potential with respect to the cathode, and the metallic wall 38 is biassed at a negative potential with respect to the grid. Oscillating electromagnetic energy is stated thereby to be generated and propagated along the wave guide.