GB290916A - Improvements in direct current electrical supply systems at constant potential - Google Patents

Abstract

290,916. Longton, H. Nov. 20, 1926. Converting pulsating currents into steady continuous currents; vacuum or lowpressure apparatus, arrangements of. - An arrangement for supplying steady current to thermionic valve circuits for filament heating or grid biassing comprises leadaluminium cells connected in shunt across the source of pulsating current. In the arrangement illustrated current from an A.C. source 1 is supplied to the primary 2 of a transformer having secondaries 9, 10, 11 associated with a resistance lamp 12 and a rectifying valve 13 so that a pulsating unidirectional voltage is produced between the connections 14, 15. Smoothing is then effected by means of the cells 25, 26 in conjunction with series chokes 23, 24 provided in one or both leads. Regulation of the output voltage at the terminals 20, 21 is effected by varying a plug connection 27 with a tapped resistance 18 and by adjustment of a contact 16 over a resistance 17 which, in series with the resistance 18, bridges the output terminals. The cells 25, 26 comprise plates 41, Fig. 4, of aluminium or " Duralumin," and plates 43 of lead-covered steel immersed in a saturated solution of ammonium borate. The casing 44 may also be of lead-covered steel so as to serve as one of the electrodes. A convenient arrangement of the parts in a casing is also described.