GB276832A - Thermionic oscillation generators - Google Patents

Abstract

276,832. Kirke, H. L. Sept. 1, 1926. By varying inductance.- In order to maintain the oscillation frequency substantially independent of the valve characteristics, the necessary phase reversal of the feed-back from the anode to the grid circuit of an oscillator valve is secured by the aid of an auxiliary valve, and the anode circuit of the oscillatory valve comprises resonant means of low impedance relatively to that valve. The Specification describes the invention with reference to an oscillator valve having a tuned anode circuit and contains a mathematical analysis of the circuit conditions necessary to maintain oscillations. In Fig. 5 the tuned anode circuit is replaced by a mechanical vibrator such as a tuning fork T coacting with a plate coil L7 and grid coil L8 respectively. The resistances R1, R4 may be replaced by inductances provided the reactance is large compared with the differential resistance of the valve for the frequencies concerned, and in general any suitable combination of resistances, inductances and transformers may be used provided that the voltage changes applies to the grid of the oscillator valve VI from the plate of the auxiliary valve V2 are approximately 180‹ out of phase with the plate voltages of the first valve.