Patent GB-462252-A (GB)
Title: Improvements in or relating to magnetron tubes and to circuit arrangements incorporating the same
IPC: H03C5/04
Filed: 1935-09-04
Abstract: 462,252. Discharge apparatus; valve circuits. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. Sept. 4, 1935, No. 24687. Convention date, Sept. 4, 1934. [Classes 39 (i) and 40 (v)] A tube, particularly for short-wave use, containing one or more electron sources and an anode in two or more parts contains also within the anode surface a substantially rectilinear normally unheated conductor, the current through which produces a circularly symmetrical magnetic field and which is disposed substantially perpendicularly to the plane dividing the anode parts. In one form, Fig. 4, two hemispherical anodes A1, A2 surround one or more punctiform or circular electron sources E, which may be directly or indirectly heated, for example, heavy emission oxide cathodes, and a tubular current bridge S through which flows the highfrequency current generated in the circuit formed by the anodes, their mutual capacity and the bridge S. The bridge S may also carry the anode supply and a modulating current, and it, or a member located inside it with the interposition of insulation O, may be extended outside the tube and may be provided with terminal spheres to serve as an aerial. The cathode leads may be twisted together and taken out in the plane dividing the anodes, or parallel to and inside or outside the bridge S, or they may be arranged in line with each other, Fig. 7 (not shown), and utilized for modulation purposes. Focusing members H, which produce a fan-shaped electron beam and may be discs or like members, may serve also as control electrodes or be connected to the cathode. The member L may be used for the production of a magnetic field, for example, for modulation in a generating tube, in which case the electron source or sources are asymmetrically arranged. The cathode may be a point-shaped arc, a vacuum spark gap, or a gas discharge. Fig. 5a shows such an arrangement. The cathode is formed by a gap F in the bridge S and the high-frequency current flowing in the bridge is carried by the discharge gap or by a capacitative shunt N which may be arranged outside the bridge and provided with apertures for the passage of electrons. The shunt N is separated from the bridge by insulation O1 and may serve as a magnetic or electrostatic control member. The annular gap between the anodes A1, A2 may be covered by a ring-shaped member, which may serve as a modulating electrode, Fig. 9 (not shown). A cylinder or a sphere may be divided by planes perpendicular to the current bridge to give three or more anodes. In one form, Fig. 11, several anodes A1, A2, A3 ... An are connected by inductances I, and the device yields a frequency n-1 times that of the input circuit K which supplies the bridge S. The highfrequency generated by a tube may be taken from the anodes by plates placed inside or outside the tube and forming condensers with the anodes. The current bridge may be insulated from the anodes and supplied with continuous or alternating-current. The anodes or the bridge, or both, may be provided with cooling fins or a cooling medium, such as air, water or oil. The tube may contain grid electrodes if desired. Frequency multiplication may be obtained by a number of anodes (more than two) working in push-pull, where the bridge carries a continuous-current. Fig. 20 shows an arrangement in which the input is applied to anodes A3 alternating with anodes A1, A2 between which the output is taken off. A receiver may comprise an aerial extension of the bridge S, Fig. 22, and three anodes, the signals being taken off at the point X between the anode A3 on which the undeflected electron stream falls and the outer anodes A1, A2. The receiver may be provided with a tuned circuit and may be brought nearly to selfoscillation, or a super-regenerative system may be used.