The GATE Grind

GATE 2022 IN – Question 21

Digital Electronics · Number systems and combinational logic · 1 mark · Multiple choice

The logic block shown has output $F$ given by ______.

Diagram for GATE 2022 IN question 21
  1. $A+B$
  2. $A\bar B$
  3. $A+\bar B$
  4. $\bar B$

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Show answer and explanation

Correct answer: (D) $\bar B$

Explanation

The first two NOR outputs are AB and AbarB. Their final NOR gives F=NOT(AB+AbarB)=NOT[B(A+Abar)]=**Bbar, D**.