GB741058A - An electronic direct current electric generating apparatus - Google Patents

Abstract

741,058. Thermionic-cathode tubes. JOHNSTONE, D. M. Nov. 17, 1953 [Nov. 19, 1952], No. 29276/52. Class 39 (1). A voltage-generator utilizing the retarding- field regime in a diode comprises a number of diodes placed in series end-to-end and heated as a whole to electron-emitting temperature. It is stated that a useful voltage independent of, and in some cases much larger than, the Peltier voltage (e.g. ¢ volt per diode), may be obtained provided one of the following combinations is used: (a) monatomic layer of emissive metal on the cathode, plain anode, (b) oxide layer on the cathode, plain anode, (c) cathode layers as in (a) or (b), anode also provided with monatomic film of low work function ; a macroscopic layer of metal on the cathode is stated not to give a useful result. As shown, a series of discs D are sealed together with insulating spacers S, each disc forming the cathode of one diode on its right-hand face and the anode of the preceding diode on its left-hand face, the anode-cathode spacing being of the order of 0.1 mm. An initial cathode and final anode are provided respectively by left and right end discs ED. The discs are heated by any means, such as hot gas G passed through perforations in the discs; or electric heating, e.g. by induction, may be used. In another form the whole assembly of discs is mounted on a central stem and enclosed within a separate envelope. A filling of inert gas at 10<SP>-4</SP>-10<SP>-5</SP> mm. may be present in a sealed envelope, or the tube may be continuously evacuated. The spaces between the electrodes may be filled with a material permeable to electrons.