The GATE Grind

GATE 2023 PH – Question 24

Electronics · basics of digital logic circuits, combinational and sequential circuits, flip- flops, timers, counters, registers, A/D and D/A conversion. · 1 mark · Multiple choice

Which one of the following options is CORRECT for the given logic circuit?

AND, NAND and OR logic circuit.
  1. P = 1, Q = 1; X = 0
  2. P = 1, Q = 0; X = 1
  3. P = 0, Q = 1; X = 0
  4. P = 0, Q = 0; X = 1

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Show answer and explanation

Correct answer: (D) P = 0, Q = 0; X = 1

Explanation

The tied NAND inputs invert P, giving $X=\overline P+PQ=\overline P+Q$. Only P=Q=0, X=1 matches a listed row.