GB318922A - Improved means for the elimination of ripples in electron valve sets - Google Patents

Abstract

318,922. Telefonaktiebolaget L. M. Ericsson. Sept. 12, 1928, [Convention date]. Thermionic amplifiers. - In a resistancecoupled amplifier arranged to eliminate the effects of disturbing ripples from d.c. mains supplying the anode and/or grid and filament potentials, one of the electrodes is supplied with ripple potentials substantially independent of the corresponding continuous potential and of appropriate amplitude and phase to effect the desired elimination in the output circuit. Thus in a twovalve amplifier, the anodes may be supplied from a resistance M, O, Fig. 1, connected across the mains B, compensation being effected by connecting the grid return lead of the first valve to an appropriate point P on the resistance M, O. In an amplifier in which grid and filament potentials are also derived from the mains, the resistance M, A, Fig. 2, filaments F1, F2, resistances rand O, N are connected in series across the mains. Grid bias for the first valve is taken from resistance r through a resistance R, and the compensating ripple is applied to the same grid from a tapping P on M. A through a condenser K whose impedance is low compared with R. Two three-valve circuits are described (Figs. 3 and 4, not shown) in the first of which two tappings are taken from the mains resistance, and the ripple therefrom applied through condensers to ends of the anode resistance of the first valve, one of these condensers being stated to increase the rectifying properties of the valve and bye-pass high frequencies across the anode resistance. The second circuit dispenses with the mains resistance and the two compensating voltages are derived from a variable resistance in conjunction with a resistance in the feed circuit of the first valve. Phase-adjusting impedances may be used to correct the phase of the compensating potentials. Specifications 240,851, 261,110 and 309,902 are referred to.