GB460689A - Improvements in or relating to magnetron tubes and to circuit arrangements incorporating the same - Google Patents

Abstract

460,689. Magnetrons ; valve generating, modulating, and amplifying circuits. TELEFUNKEN GES. FUR DRAHTLOSE TELEGRAPHIE. May 18, 1936, No. 14100. Convention date, May 18, 1935. [Classes 39 (i) and 40 (v)] In a split-anode magnetron, modulation or control of the oscillating current is effected by auxiliary electrodes situated either in or behind the gaps between adjacent anodes, or behind grid-like or perforated anodes, and supplied with modulation or other control voltages or currents. In the form shown in Fig. lb, two wire auxiliary electrodes H1, H2 are placed in the gaps between anodes A1, A2. Modulating currents from the source M are passed through the two wires connected in series by loop B, and control the oscillating current magnetically. In another form, Fig. 2b, semicylindrical auxiliary electrodes H1, H2 are placed behind perforated anodes A1, A2, and are connected together and to a source of modulating voltage, the control here being electrostatic. A negative bias is applied relative to the cathode. In a further modification, Fig. 3a, four anodes A1 . . . A4 are connected together alternately and four auxiliary strip electrodes H1 .. H4 are similarly connected alternately to the ends of the coil st. The valve may act as an externally controlled amplifier, or may be worked just below the point of incipient oscillation, when the coil st is supplied with a control frequency equal to the generated frequency (which may be obtained by back-coupling from the coil N) or to a multiple or submultiple thereof. The auxiliary electrodes may be at cathode potential or biassed negatively by half the anode voltage. Working data for maximum efficiency in a four anode tube with only two electrostatic strip control electrodes are given.