GB473028A - Improvements relating to thermionic valve circuits - Google Patents

Abstract

473,028. Valve amplifying circuits. WHITE, E. L. C. April 8, 1936, No. 10300. [Class 40 (v)] A circuit for modifying the phase of signal potentials comprises a valve having an impedance in the cathode lead so that signals appear at the cathode and anode which after modification by a reactive impedance are combined to produce the desired phase modification. Fig. 1 shows a pentode valve with load resistances 4, 7 of 1000 ohms each and a bias resistance 5 of 70 ohms for operation at frequencies of 10-100 kilocycles. A resistance 8 of 10,000 ohms in series with a condenser 9 of À0004 microfarads is connected between the anode and cathode to modify the phase of the output potentials. Fig. 2 shows an arrangement in which condenser 17 provides phase correction and load resistance 16 has substantially twice the value of the resistance 15 in the cathode lead. Outputs of opposite phase are applied to valves 13, 14 whose outputs are combined and taken from terminals 25, 26. Phase correction may be alternatively effected by inductances or by composite impedances instead of by condensers. The reactive impedance may be variable.