GB1059852A - Regenerative amplifiers with response controlling means - Google Patents

Abstract

1,059,852. Transistor regenerative circuits. CARTER PRODUCTS Inc. Feb. 14, 1964 [Feb. 15, 1963], No. 6386/64. Heading H3T. A regenerative switching circuit as described in Specification 1,059,851 comprising an amplifier such as a transistor provided with positive feedback to render it capable of behaving as a two-state trigger circuit and having means for periodically rendering the positive feedback ineffective so that the circuit takes up an output condition in response to an input signal which is independent of the previous output condition of the circuit, is modified by the provision of further smoothed positive feedback from the output to the amplifier to ensure that the output responds to changes in input only after a delay thus eliminating the effects of spurious signals and noise. In the circuit illustrated which is the same as that of Fig. 8 of Specification 1,059,851 with the addition of T-network R 120 , R 121 , C 120 reciprocally coupled transistor pair Q 100 , Q 101 is energized from unsmoothed fullwave rectifier source comprising transformer secondary SW 100 and associated rectifier diodes. The circuit consequently ceases to respond to input signals applied between terminals 201, 202 at periodic intervals when the supply voltage falls to zero. The circuit then resumes its previous state or changes to its other state depending upon whether the input has changed or not; however, in order that the circuit should not change state in response to spurious changes of input caused for example by noise, positive feedback from the collector of transistor Q 102 of the output transistors Q 102 , Q 103 controlling relay K 100 is fed back to the base of transistor Q 101 . The feedback signal is smoothed by and stored upon capacitor C 120 so that changes in input signal of short duration do not influence the output but a sustained and definite change will eventually cause a change in state.