Question

Which of the following logic expressions represents the logic diagram shown?

(a) X=AB’+A’B

(b) X=(AB)’+AB

(c) X=(AB)’+A’B’

(d) X=A’B’+AB

The question was asked during an interview.

My question comes from Combinational Circuits in chapter Combinational Circuits of Digital Circuits

Answer 1

The correct choice is (d) X=A’B’+AB

Explanation: 1st output of AND gate is = A’B’

             2nd AND gate’s output is = AB and,

             OR gate’s output is = (A’B’)+(AB) = AB + A’B’.