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GATE 2014 EC (EC1) – Question 24

Digital Circuits · Combinatorial Circuits · 1 mark · Multiple choice

The pass-transistor circuit uses identical NMOS devices with threshold 1 V. Ignore body effect. Find output voltages at P,Q,R, respectively.

Diagram for GATE 2014 EC (EC1) question 24
  1. 4 V, 3 V, 2 V
  2. 5 V, 5 V, 5 V
  3. 4 V, 4 V, 4 V
  4. 5 V, 4 V, 3 V

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Show answer and explanation

Correct answer: (C) 4 V, 4 V, 4 V

Explanation

Each transistor has its own gate held at5V and threshold1V. The first NMOS passes a high level only up to5−1=4V. Subsequent devices can pass that existing4V level because their gates remain at5V. There is no additional threshold loss at each stage. Thus **P=Q=R=4V,C**.