Patent GB-499487-A (GB)
Title: Improvements in or relating to electron discharge devices for voltage amplification or control
IPC: H01J43/02
Filed: 1937-04-21
Abstract: 499,487. Electron multipliers; valve circuits. KRAWINKEL, G. April 21, 1937, Nos. 11376, 11377, 11378, 11379, and 11380. Convention dates, April 25, 1936, May 26, 1936, June 10, 1936, June 16, 1936, and Jan. 11, 1937. [Classes 39 (i) and 40 (v)] In voltage amplification or control the potential of a floating electrode or electrode system is varied in accordance with a control potential by bombarding with a primary electron stream an electrode adapted to emit secondaries, the resulting potential of this electrode or the system allied thereto being used for amplification etc.; the control potential varies one or more of (a) the intensity or speed of the primary stream, or (b) the potential of a collector electrode for the secondaries. The primary stream may be obtained from a thermionic, photo-electric, cold or secondary emission cathode; the secondary emission from the bombarded electrode may be enhanced by heating, by electron bombardment or otherwise. In one form, the primaries from the cathode K, Fig. 1, are accelerated by a grid G to bombard the floating secondary emitting electrode P, the secondaries being collected by an electrode C; control potentials may be applied to the grid G, collector C or to an intensity control grid g; the potential that the electrode P attains is mainly dependent on the potential of the collector C. An output current can be obtained from the connection between the collector and cathode. The potential control may be applied from the electrode P to cathode-ray tubes, thermionic amplifiers, regulators, rectifiers and oscillation generators. In one form, two electrodes P P', Fig. 4, are connected to the grids g, g<1> of a double triode ; a condenser may be interposed in the connection between the electrode P and grid g in the associated valve. In a rnodification, the electrode P, Fig. 5, is connected to a grid g<2> in the primary stream, the grid taking up some electrons in part dependent on the condition of the electrodes P ; an impedance may be included in the connection between the grid g<2> and electrode P and by backcoupling oscillation may be produced. A collecting electrode g<3> is next to the secondary electrode, but the latter may be connected to an adjacent grid, the collector grid being nearer the cathode. The secondary electrode P, Fig. 9, may be of grid form with an output anode A beyond the grids, the flow to the anode being controlled by the floating system P, g<2>. Two sets of electrodes each comprising a floating system may be arranged in cascade to control now to a final output anode. A floating system P, g<3>, Fig. 11, may be connected to an amplifying section in a common envelope ; the collector g<3> is connected to the cathode K<2>. Input and output impedances Ri, Ra are connected as shown ; bias may be given to the primary cathode. Modifications of this circuit have no connection between the grid g<2> and the cathode K<2> and also a common cathode. To allow for gradual return of the electrode to a datum potential, a high resistance or semiconducting leak is provided ; the high resistances may be discharge tubes such as biassed diodes or grid controlled discharge valves. In the Specification as open to inspection under Sect. 91, are also described (i) the application of the floating principle to a condenser or mosaic ; (ii) the use of two secondary emitting electrodes with one or two cathodes, the emission from one impinging on the other ; the two may be connected ; and (iii) an arrangement where the potential of the secondary emitting electrode is controlled by connection to the output electrode of a triode. This subject-matter does not appear in the Specification as accepted.