GB545123A - Improvements in or relating to electron multiplier apparatus - Google Patents

Abstract

545,123. Valve circuits; electron multipliers. BOSCHE, F. J. G. VAN DEN., and VACUUMSCIENCE PRODUCTS, Ltd. Aug. 7, 1940, Nos. 12705/40 and 1693/41. [Classes 39 (i) and 40 (v)] In electron discharge apparatus in which the tube includes a byepass electrode in the electron path, a resistance or impedance is arranged in series with the supply voltage thereto and the voltage of the byepass electrode in the absence of space current is greater than that of the next succeeding accelerating or collecting electrode but of the same order of voltage when space current flows. In this way a large slope may be obtained without excessive current at the anodes. The impedance in series with the byepass electrode may be frequency selective so as to extract a selected frequency. Fig. 4 shows a radio receiver using an electron multiplier as the intermediate frequency amplifier which is provided with byepass electrodes 31 associated with tuned circuits 41 to increase the selectivity. Auxiliary electrodes 47 may be provided in front of the secondary cathodes 26 as described in Specifications 516,621 and 531,541 and the byepass electrodes may be immediately in front of the secondary electrodes or in front of the auxiliary electrodes. A photoelectric cathode may be used for relay operation and modulated light may be used so that the apparatus is rendered frequency selective by the provision of tuned impedances in the circuits of the byepass electrodes.