Refer to the logic circuit shown in the figure. For the two input combinations (A = 1, B = 1) and (A = 0, B = 1), respectively, what are the corresponding output values Y?

Question

G1 Physics · Accepted Answer

From the circuit, A is first inverted to give Ā. The upper gate gives Ā+B. The lower AND gate gives ĀB. These two outputs enter a NOR gate, so Y = overline[(Ā+B)+ĀB]. Using absorption, (Ā+B)+ĀB = Ā+B. Therefore, Y = overline(Ā+B) = A B̄. For A = 1 and B = 1: Y = 1×0 = 0. For A = 0 and B = 1: Y = 0×0 = 0. Hence the outputs are 0, 0 respectively. Correct option: C.