GB243038A - Improvements in and relating to amplifying apparatus, particularly for wireless reception - Google Patents

Abstract

243,038. Taggart, J. Scott-. May 24, 1924. Thermionic amplifiers and detectors.-In order to minimize the tendency to self-oscillation, due to interelectrode capacity coupling, in a multistage high-frequency amplifier, the chain of circuits comprising the receiver are so arranged that tuned and untuned circuits alternate. As shown in Fig. 1, the tuned grid circuit L1, C1 is followed by an aperiodic plate circuit L3; the grid circuit of the following valve is untuned whilst its plate circuit C2, L4 is tuned. Fig. 4 shows the same system applied to three highfrequency amplifiers followed by a detector. Reaction may be applied to an intervalve circuit, or direct to the aerial as at L2, Fig. 1. In Fig. 5 a choke coil L6 shunted by a condenser C4, forming an aperiodic system, is interposed between the tuned circuits L1, C1, and L4, C2. The choke coils L3, Fig. 1, L2, L5, Fig. 4, and L6, Fig. 5, are preferably wound with highresistance wire; or other methods of deliberate damping may be utilized. According to the Provisional Specification the various tuning condensers may be controlled by a single handle. Specification 149,199 is referred to.