GB574453A - Electron devices of the magnetron type - Google Patents

Abstract

574,453. Electron oscillators. STANDARD TELEPHONES & CABLES, Ltd. (Western Electric Co., Inc.). March 28, 1942, No. 4165. [Class 39 (i)] A unidirectional voltage is applied between a pair of plane parallel plates and a constant magnetic field is established parallel to the plates. A source of electrons is placed so that electrons enter and travel laterally'in the space between the plates in a series of approximately cycloidal hops, the plate spacing, voltage, and magnetic field strength being so adjusted that the electrons just fail to reach either of the plates. The electrons are then subjected, either before or during passage through the plates, to an alternating electric field whose lines of force are perpendicular to the plates and whose frequency is substantially that of the hops, the adjustments being such that those electrons which have gained energy from the alternating field are removed therefrom by collection on one of the plates, so that they take no further part in the operation of the device. Electrons emitted from filament 47, Fig. 5, travel in cycloidal hops between the plates 45, 46 under the influence of the positive potential on 45 ; plate 46 is at or near cathode potential. If an alternating potential of frequency equal to that of the electron motion is applied to plates 45, 46 by input line 44, out-of-phase electrons emitted during the positive half-cycle will absorb energy from the field and increase the amplitude of successive cycloidal hops, while in-phase electrons emitted during the negative half-cycle will give energy to the field and their amplitude will decrease. A net gain of energy will result if out-of-phase electrons are removed rapidly from the field ; this may be done by causing them to strike the plate 45, or the plate 46 if this is provided with a suppressor grid for secondary electrons. In the Figure, out-ofphase electrons are removed by separate plates 48, 49 which are either nearer together, or at a higher voltage, than plates 45, 46 or are provided with baffles 50. In-phase electrons then give up energy to plates 51, 52 which are connected to output line 53. The spent electrons are collected either by a target 54 or by a projection 34 on plate 51. Fig. 6 shows a repeater in a wave-guide, from which it is sealed by glass partitions 57. Projections 60, 61 from the wall of the guide terminate in plates 64, 65, plate 65 being insulated from 60 and at a positive potential. Electrons from cathode 62 follow cycloidal paths, out-of-phase electrons being removed by a projection 67. In Fig. 9, plates 121, 122 form a quarter-wave line terminated by capacity 123. Electrons emitted from strip cathode 127, or an electron gun, give up energy in decreasing cycloidal hops until they strike the collector 125. A suppressor grid 128 is provided. The plates may also be tuned to full-wave oscillation, being supported at the nodes and tapped at. a suitable point by the output line.