GB291493A - Improvements in or relating to wireless receiving apparatus - Google Patents

Abstract

291,493. Midgley, A. H. Feb. 24, 1927. Thermionic amplifiers and detectors.-In a high-frequency receiver including a thermionic valve having in its anode circuit a resistance of the order of 2 megohms, means are provided for tuning the anode circuit in such a manner as to prevent leakage of electrons except through the anode resistance. Fig. 1 shows a valve which may be of the type described in Specification 280,981 in which the anode A1 is connected through a blocking condenser C1 to the grid G2 and the anode-cathode circuit Al K is tuned by the circuit I C. The inductance I and condenser C may be in series or parallel with one another and may be arranged in parallel as shown or in series with the anode resistance R. In the latter case the resistance R is shunted by a condenser. When a parallel combination is employed in parallel. with the resistance R a blocking condenser C2 is used to avoid short-circuiting the valve. Fig. 5 shows the application to a threeelectrode valve preferably having small electrodes as described in Specification 256,299. Fig. 7 shows the application to a valve having an auxiliary anode Aa in which case the auxiliary anode circuit is tuned and both anode circuits include resistances R. R2 of the order of two megohms, while the output may be taken directly from the auxiliary anode Aa. In a modification (Fig. 4 not shown) the output is through a transformer comprising the anode tuning circuit as the primary and a secondary connected to the grid of the succeeding valve. Specifications 272,294 and 275,387 also are referred to.