GB778111A - Improvements in or relating to electrical regulating circuits - Google Patents

Abstract

778,111. Automatic voltage and current control systems; automatic current regulation. MULLARD RADIO VALVE CO., Ltd. Aug. 12, 1955, No. 23309/55. Class 38 (4). In a D.C. voltage or current regulator, of the type in which a transistor T1, Fig. 1, has its collector-emitter path in series between source and load terminals I, O, respectively, the base of transistor T1 is controlled by the output of a second transistor T2 in the latter's collectoremitter circuit. This output varies in response to changes in the voltage difference between a reference source B1 and a variable control resistor R1, which are connected in series in the base-emitter circuit of transistor T2 and through which passes the output current of the network to the load R3 connected across terminals O, Oc. The transistor T1 is thereby controlled to maintain a substantially zero value of this voltage difference and a stabilized value of current in the load R3 determined by the setting of resistor R1. A separate source B2 provides a steady current in the collector emitter circuit of transistor T2. A constant voltage may be obtained from the network across terminals O, Ov, in which case R3 is a resistor incorporated in the network which influences the value of voltage maintained. In a modification, Fig. 2, the source B1 and resistor R1 are reversed in position, whereby the separate source B2 is dispensed with; and an amplifying transistor T3 is connected between the output of transistor T2 and the base of transistor T1. In the case of current regulation only, the source and load terminals may be inverted in either arrangement so that the regulation is forwardly-acting rather than retroactive.