| 摘要 |
984,234. Tunnel-diode monstable circuits. NATIONAL CASH REGISTER CO. March 14, 1962 [April 17, 1961], No. 21184/63. Divided out of 984,233. Heading H3T. In a monostable circuit for performing logical operations and comprising a tunnel diode D connected in series with a load resistor R and an inductor L, in which input signals are applied via terminals A, B to the junction point of the diode and the inductor and the values of the resistor R and of the bias voltage Vc are so chosen that the diode is normally biased to a stable condition on the low-voltage portion of its characteristic, Fig. 3 (not shown), but may be excited to an unstable condition on the highvoltage portion of its characteristic by the application of positive-going clock pulses at terminal C, the input signals, however, being either of zero or negative value and the negative input signals inhibiting the action of the clock pulses so that the diode is triggered to its unstable state only when the input signals occurring simultaneously with a positive-going clock pulse are of zero value, the clock pulses are each followed after a predetermined interval by a negative-going re-set pulse, Fig. 2, this latter pulse restoring the tunnel diode, if in its unstable state, to its stable state so as to produce sharply defined pulses in the output circuit. In the circuit shown the inductor L constitutes the primary winding of an output transformer having two oppositely-poled secondary windings. It can thus be seen that if zero-level signals are given the value zero and negative signals the value unity, winding 52 delivers a conventional OR-output while winding 51 delivers the converse of this, i.e. a NOT-AND output in which a unity output occurs when both inputs are zero. |
