Improvements in or relating to a control circuit employing semi-conductor devices

摘要

826,555. Circuits employing bi-stable magnetic elements. SPERRY RAND CORPORATION. Jan. 25, 1957, No. 2840/57. Class 40 (9). [Also in Group XL (c)] In a circuit comprising a saturable core T2 biased by current in a winding 50 to a saturated state, a further winding 46 is connected to a series of semi-conductors 40, 41 and 42, current due to charge carrier storage set up by input signals at terminals 52, 53 or 54 being supplied through the semi-conductors to drive the core into an unsaturated region. A square clock pulse waveform A is applied over terminal 47 and isolating diodes 43, 44 and 45 to the diodes 40, 41 and 42. During the negative-going waveform diode 43 is reversely biased and no current flows in winding 46, and in the succeeding positive-going wave a small current passes through the back resistance of diode 40 to cause a small current in the winding but since this is insufficient to drive the core from its saturated state, no output appears across the winding 48. If, during the next negative-going clock pulse an input pulse is applied to the junction of diodes 40, 43 forward current flows in diode 40, driving the core further into the saturated region. When the input pulse ceases and the clock pulse reverses, considerable current flows in the reverse sense of diode 40 driving the core from one saturated condition to the other, Fig. 3 (not shown), to produce an output pulse on winding 48. This output pulse is terminated by the next negative-going clock pulse which allows the bias source to restore the core to its original condition. The input signal may be applied over a transformer, Fig. 1 (not shown), and blocking pulses applied to the secondary to prevent reaction on the input due to clock pulses. The circuit may be regarded as an OR gate since when any one of the diodes 40, 41 and 42 is rendered conducting an output appears on winding 48. A winding 55 is biased from a battery 56 so that the output is at battery potential except in the case when an output appears across winding 55. In this manner the circuit may be regarded as an AND gate since only in the absence of any input does the output correspond to the battery 56. The circuit may be arranged so that more than one rectifier 40 must be energized before an output occurs. Specification 826,556, [Group XL (c)], is referred to.