GB322271A - Improvements in or relating to radio valve circuits - Google Patents

Abstract

322,271. Igranic Electric Co., Ltd., and Hodgson, A. D'A. Sept. 28, 1928. Thermionic amplifiers employing valves with two or more grids have the input circuit connected between the inner grid and the filament, and the output circuit backcoupled to the outer grid. As shown in Fig. 2, the plate circuit includes a coil 2 with a resistance 6 connected across an extension, a slider or tapping on the resistance being connected to the outer grid of the valve. The slider may make direct contact with the coil extension (Fig. 1, not shown), or the resistance 6 may be connected across a coil coupled to the plate coil (Fig. 3, not shown). The next valve 4 may be coupled by a capacity 3 or by magnetic coupling to the coil 2. In another form shown in Fig. 4, reaction to the outer grid is taken from a resistance 6 connected across a coil 7 which is coupled to the grid coil 9 of the next valve 4, voltage for the outer grid being supplied by a lead X. A further modification, Fig. 6, employs an autotransformer 11 as the intervalve coupling, the outer grid being associated with a coil 7 coupled to the coil 11. The reaction may be employed to strengthen the received signal, to neutralize a tendency to self-oscillation, or to correct the frequency characteristic of the coupling system.