GB648884A - Improvements in or relating to electronic cascade amplifiers energized by alternating current - Google Patents

Abstract

648,884. Valve circuits. SUMMERLIN, F. A., and SPERRY GYROSCOPE CO., Ltd. Nov. 6, 1946, No. 32987. [Class 40 (vi)] The invention relates to A.C. operated amplifiers and phase or sense sensitive demodulators or rectifiers of the type comprising successive stages each including two vacuum or gas discharge valves 1, 2 and 18, 19 having the A.C. energizing supply fed to the two anodes of a stage in phase and to the succeeding stage in phase opposition. The signal is applied in phase opposition to the control grids 5 and 6 and the resulting voltage developed across the loads 13, 14 in the anode circuits of the first stage during the first half-cycle of the supply voltage is stored in capacitor 29 connected between the anode ends of the loads and fed to the grids 22, 23 of the succeeding stage to control the anode current of that stage during the next half-cycle. The present invention provides in such a circuit additional capacitors 30, 31 connected across the whole or part of each of the anode loads 13, 14 to supply bias for the succeeding stage. The two condensers may be adjustable and preferably provide time constants shorter than that of the circuit comprising the anode loads and capacitor 29. In the amplifier shown, the signal is applied through transformer 9 though a direct connection may be preferred, the output is taken from transformer 26. Resistor 17 provides the bias for the first stage. The supply voltage is applied through transformer 16 and has a frequency of 400 c/s. If the input and supply voltages have the same frequency the circuit is phase-sensitive.