GB223589A - Improvements relating to electrical discharge devices for use as translating apparatus - Google Patents

Abstract

223,589. Westinghouse Brake & Saxby Signal Co., Ltd., (Assignees of Waterman, F. N.). Oct. 19, 1923, [Convention date]. Thermionic relays.-A tube for use as a translator comprises a source, of electrons, such as a. filament cathode, an anode, and a thermosensitive element, the temperature of which is raised by bombardment of the anode by electrons. As shown in Fig. 1 the thermo-sensitive element 4, which may consist of material such as cupric oxide having a negative resistance coefficient, is mounted between a cylindrical anode 3 wholly or partly surrounding the filament, and a cylinder 5, which is connected, through a lamp E or other indicator and the secondary 17 of a transformer with the anode. The filament is connected through a switch 9 with a tapping on the secondary 6 of a transformer which supplies the potential for the anode; or the switch may be connected at 12 between the anode and the transformer, or in the lead 7 common to both the filament and anode circuits. The bulb may be exhausted or contain a non-oxidizing gas. Normally the current from the secondary 17 is insufficient to light, the lamp E, but, when the switch 9 is closed, the anode is heated bv electron bombardment, and the resistance of the element 4 is reduced, with the result that the lamp is lighted. Several such cylindrical anodes and sensitive elements, each controlling a, separate lamp, may be mounted around a common filament; or the anodes and sensitive elements may be of segmental form. In a modification a grid electrode is interposed between the filament and anode, and is connected through a switch with the secondary of a transformer supplying the current for the filament and lamp, and the potential for anode. The grid potential may be positive or negative with respect to the filament so that the lamp is either lighted or extinguished when the switch is closed. In a further modification the passage of electrons to the anode is controlled by a magnetic field produced by a. winding mounted around the outer cylinder and connected through a switch with the secondary of a transformer.