GB540944A - Improvements in or relating to electron discharge valves and operating circuits therefor - Google Patents

Abstract

540,944. Thermionic valves. BULL, C. S., and HILL, S. April 4, 1940, Nos. 6077 and 7724. [Class 39 (i)] In a thermionic valve the control electrode CG is at such a negative potential that the anode current is exponentially related to the potential of the control electrode and the electron emission which reaches the control electrode forms a high proportion of the anode current; the input power absorbed at the control electrode at high frequency is thereby reduced as relatively few electrons are returned to the cathode. In one form an additional electrode AG, Fig. 2, is inserted between the cathode and control electrode and is at a potential in the range + or - 2 volts of the cathode potential In another form the emissive surface of the cathode C, Fig. 3, is restricted to a surface bounded by the angle AB; it also need not extend the whole length of the cathode. A screen grid SG is placed with turns only on the use side of the cathode as described in Specification 534,208; the emitter is shown in Fig. 2 applied to an electron multiplier as set forth in that Specification. Sizes of one construction are given. Specification 452,372 also is referred to.