GB481996A - Improvements in or relating to grid-controlled electron multiplier circuits - Google Patents

Abstract

481,996. Electron-multiplier circuits. GENERAL ELECTRIC CO., Ltd., FARREN, L. I., and GEORGE, E. P. Nov. 30, 1936, No. 32796. [Classes 39 (i) and 40 (v)] In order to reduce the effect of undesired variations in the supply voltages and other constants on the output current and the gain of a grid-controlled electron-multiplier, negative reaction is introduced. As shown in Fig. 2, a resistance R1 is inserted in series with the output resistance R2, and a connection is made from the resistance R1 through a bias battery Eg to the input or grid circuit of the multiplier. If stability is required only when the multiplier is functioning as a direct-current amplifier, the resistance R1 may be shunted by a condenser, alternating- current signals then being unaffected by the feed-back, Fig. 3 (not shown). If the feedback is to be ineffective for slow variations, series condensers are connected in the feedback path, Fig. 4 (not shown). In Fig. 5, two feed-back resistances R1, R3 are provided in series in the output circuit, the resistance R1 being shunted by a condenser C and connected to the grid circuit through a battery Eg a resistance R4 and a conductive path, so as to provide feed-back for slowly-varying signals ; whilst the resistance R3 is connected through a condenser C1 to provide feed-back for A.C. signals. The feed-back resistances may be replaced by frequency-dependent impedances. The electron-multiplier has a cylindrical focusing electrode 4 connected to the primary cathode 2 and partially enclosing the control grid 3. A screen 5 is situated in front of the output anode 6.