GB219705A - Improvements in electron discharge devices and circuit arrangements therefor - Google Patents

Abstract

219,705. British Thomson-Houston Co., Ltd., (Assignees of Hull, A. W.). July 27, 1923, [Convention date]. Addition to 205,058. Thermionic amplifiers and detectors.- Electron discharge devices comprising a rectifying portion and an amplifying portion of the type described in the parent Specification are connected in cascade to produce successive amplification and are oppositely connected to an alternating current source in order to produce full-wave rectification. As applied to a wireless receiver, the rectifying portions 4, 5 of the devices 2, 3 are connected to opposite terminals of the supply transformer 9, from which the heating currents for the auxiliary cathodes 2 are tapped off as shown. The anodes 7 are connected through a. common resistance 10 to an intermediate point on the transformer 9. The main cathodes 5 are also connected to a, common point across condensers 11 which serve in combination with the resistance 10 to smooth out fluctuation in the current supplied to the anodes 7. The auxiliary cathode 4 of the device 1 serves merely to heat the main cathode 5, for which purpose only a comparatively small alternating voltage is supplied from the source, as shown, thereby minimizing disturbances in the detecting circuits. The rectified plate voltage for the valve 1 is supplied by a tapping from the rectifying portion of the valve 2. Instead of the coupling transformers 13, 14 between the valves 2, 3, a choke coil in series with a resistance shunted by a condenser may be used. Fig. 3 shows a duplex tube for securing full-wave rectification. Two auxiliary cathodes 25 are surrounded by one cylindrical main cathode 26 and are separated by a partition 27. There is a single control or grid electrode 28 and one anode 29. the circuit connections to the supply transformer 9 being identical with those shown in Fig. 1.