Choose the correct logic circuit for the given truth table having inputs A and B. [figure]
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Answer
(1) [figure]
Solution
From the table, Y = 1 exactly when A = 1, whatever B is Y = A.
(1) Y = A (A + B) = A + AB = A(1 + B) = A ✓
(2) Y = A (A + B) = AB; for A = 1, B = 0 it gives 0 ✗
(3) Y = A (A + B) = 0 for every input ✗
(4) Y = (A + B) B = B; for A = 1, B = 0 it gives 0 ✗
Answer: (1)