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Choose the correct logic circuit for the given truth table having inputs A and B. Truth table (A, B, Y): 0 0 0; 0 1 0; 1 0 1; 1 1 1. [Figure: four circuits, each ending in an AND gate. (a) A and B go to an OR gate; the OR output and A (by a separate wire) go to the AND gate. (b) Same, but the separate A wire passes through a NOT gate. (c) Same as (a), but the OR output passes through a NOT gate. (d) A and B go to an OR gate; the OR output and B go to the AND gate.]

Asked in JEE Main 3rd April 1st Shift 2025 · Gate combinations and truth tables

• (1) Y=A·(A+B)
• (2) Y=A·(A+B)
• (3) Y=A·(A+B)
• (4) Y=B·(A+B)

Step-by-step solution

Why the other options are wrong

• (2) Gives A B, which is 1 only for A=0,B=1.
• (3) Gives AAB=0 for every input.
• (4) Gives B, but the table shows Y=A.

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