GB488508A - Improvements in and relating to thermionic oscillation generators - Google Patents

Abstract

488,508. Valve generating circuits. TELEPHONE MANUFACTURING CO., Ltd., and PADDLE, L. H. March 4, 1937, No. 6439. [Class 40 (v)] In an ultra short wave oscillator comprising a number of valves arranged with their anodegrid paths in series and with an inductance connected between one pair of like electrodes and a connection of negligible inductance between the other pair, the cathodes are caused to oscillate relatively in potential by including in the cathode circuit a tuned circuit resonating at the oscillation frequency. In Fig. 1, the oscillator comprises a pair of directly-heated triodes V1, V2 with a direct connection between the grids and with an inductance L1, in the form of a loop or a Lecher-wire system, connected between the anodes. The filaments are connected to the supply B2 through Lecher wires LW1 and LW2 tuned to the oscillation frequency, or alternatively, Lecher wires and high frequency chokes may be used, Fig. 2 (not shown). Fig. 3 is characterized by the use of a Lecher-wire system LW3 in the anode circuit and by the connection of a tank circuit, comprising inductance L2 and condenser C2, between the cathodes. Greater high frequency stability may be achieved by connecting two variable condensers in series with the tank circuit, Fig. 4 (not shown). The connections between grids and anodes may be interchanged throughout. When more than two valves are employed they may be interconnected as described in Specification 475,673.