Improvements in or relating to electrical circuit arrangements for performing invert operations

摘要

1,099,848. Transistor switching circuits. INTERNATIONAL BUSINESS MACHINES CORPORATION. Jan. 7, 1966 [Feb. 26, 1965], No. 782/66. Heading H3T. In a switching circuit having negative feedback and tending to produce unwanted oscillation, a further negative feedback path is made effective by the output voltage so as to oppose unwanted oscillation. As shown, logic signals at 21 are coupled via an AND gate 20 and diode 25 (which may be part of an OR gate) to an emitter follower 10 feeding an amplifier 11. Feedback via anti-saturation diode 38 tends to produce high frequency oscillation. This is prevented by resistor 33 which introduces Miller effect, thus delaying the response when the input is rising, the Miller effect being inhibited by diode 40 becoming conductive when the input is falling.