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GATE 2019 EC – Question 49

Digital Circuits · Sequential Circuits · 2 marks · Multiple choice

The state transition diagram for the circuit shown is

Diagram for GATE 2019 EC question 49
  1. Diagram (A)
  2. Diagram (B)
  3. Diagram (C)
  4. Diagram (D)

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Show answer and explanation

Correct answer: (C) Diagram (C)

Explanation

The multiplexer selects the NAND feedback when $A=1$ and feeds back a value that gives $D=\bar Q$ or $D=Q$ depending on $A$. Working through the two cases gives the transitions in diagram (C), which matches the official key.