GB359890A - High frequency coupling system for thermionic amplifiers - Google Patents

Abstract

359,890. Electric transformers. HAZELTINE CORPORATION, 15, Exchange Place, Jersey City, New Jersey, U.S.A.-(Assignees of Wheeler, H. A. ; 78, 22nd Street, Jackson Heights, New York, U.S.A.) April 23, 1930, No. 12580. Convention date, June 20, 1929. [Class 38 (ii).] In a high frequency amplifier the inter-valve coupling network comprises a primary circuit coupled to a tunable secondary circuit and including in series an impedance capacitively reactive and an impedance inductively reactive and means independent of the capacitively reactive impedance to prevent regenerative action throughout the tuning range. The couplings are preferably of the type described in Specifications 273,639 and 315,399, [both in Class 40 (v), Wireless signalling &c.]. Fig. 1 shows high frequency amplifying valves 1, 2 and a detecting valve 3 having similar input circuits comprising primary windings 13 tuned by condensers C3 to a frequency just below the lowest frequency in the operating range, windings L2 which serve as additional primary windings and for neutralizing and secondary windings L1 tunable by condensers C1. In a modification a mixed coupling is employed which forms the subject-matter of Specification 359,571, [Group XL]. Fig. 5 shows the coil construction which forms the subject-matter of Specification 359,901, coils L1, L2 being tightly coupled and coil L3 loosely coupled to L2 and serving as an electrostatic and electromagnet shield since the winding L3 is shunted by a capacity C3 of relatively low reactance. Winding dimensions and inductance values are given in the Specification.