The truth table for the following logic circuit is :

Solution

Physics sir · 3 steps

Follow each wire to its gate. The two ANDs build XOR, and the bubble on the final gate flips it.

1. Trace the crossing wires. The top AND gate gets A and, through the crossed wire, B̄. The bottom AND gate gets B and Ā. So the two outputs are AB̄ and ĀB.
2. Final NOR gate. The last gate has a bubble at its output, so it is a NOR gate. It ORs the two products and then inverts the result.

   Y = AB̄ + ĀB̅ = A ⊕ B̅

   A, B	AB̄	ĀB	Y
   0, 0	0	0	1
   0, 1	0	1	0
   1, 0	1	0	0
   1, 1	0	0	1

3. So. The output column reads 1, 0, 0, 1. The circuit is an XNOR gate, and only option (d) shows this column.

The idea to keep. Write the Boolean output of every gate in order from left to right before you check any row. AB̄ + ĀB is XOR, and a bubble after it makes XNOR.

Answer from the NTA final answer key. Solution by PrepWiser.