GB838247A - Improvements in or relating to transistor circuit arrangements - Google Patents

Abstract

838,247. Electronic stepping registers. PHILIPS ELECTRICAL INDUSTRIES Ltd. Nov. 22, 1957 [Nov. 27, 1956], No. 36486/57. Class 106 (1). In a transistor chain circuit in which the presence or absence of stored free charge carriers in the base zone of a transistor determines the free charge storage in the base zone of a succeeding transistor by means of pulses fed to the transistor collectors at predetermined time intervals, the collector of the preceding transistor is connected through a resistor conducting in both directions to the base of the succeeding transistor, the value of this resistor together with that of a resistor in the collector circuit of the preceding transistor being sufficiently large to prevent any appreciable leakage of free charge carriers from the succeeding transistor in the interval between successive pulses supplied to the two transistors. In the circuit shown, Fig. 1, odd and even transistors receive pulses alternately from separate sources A, B, Fig. 2, each pulse being followed by a charge-erasing pulse A', B' applied to the bases. If initially no transistor contains free charge carriers, the first pulse A will charge the bases of even transistors 2, 4, 6 by current flow through resistors 19, 21, 23. When the following pulse B is received, these transistors will be highly conductive and no charge will be imparted to the bases of the odd transistors 3, 5. If free charge carriers are introduced into transistor 1, e.g. by a light pulse, when the next pulse A is supplied, a current I 1 will flow, thus preventing a charge being imparted to transistor 2: thus the next pulse B will not cause transistor 2 to conduct (see absence of I 2 , Fig. 2) but will charge transistor 3 which then conducts (current I 3 ) upon receipt of the next pulse A and so on. Thus the charge imparted to transistor 1 is shifted along the chain as absence and presence of charge alternately (see also I 4 -I 6 , Fig. 2). The circuit may be used for shifting binary information, e.g. in a calculating-machine or automatic telephone system. Specification 835,907 is referred to.