8/18/2023 0 Comments Totem pole output what isthe output transistors Q3 and Q4 form a totem-pole output arrangement. If A or B is low, the base-emitter junction of Q1 is forward biased and its base-collector junction is reverse biased. Then there is a current from Vcc through R1 ti the base emitter junction of Q1 and into the LOW input, which provides a path to the ground for the current. Hence there is no current into the base of Q2 and making it into cur-off. The collector of Q2 is HIGH and turns Q3 into saturation. Since Q3 acts as a emitter follower, by providing a low impedance path from Vcc to the output, making the output into HIGH. At the same time, the emitter of Q2 is at ground potential, keeping Q4 OFF. When A and B are high, the two input base emitter junctions of Q1 are reverse biased and its base collector junction is forward biased. This permits current through R1 and the base collector junction of Q1 into the base of Q2, thus driving Q2 into saturation. As a result Q4 is turned ON by Q2, and producing LOW output which is near ground potential.
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