question_answer

The following configuration of gate is equivalent to  [AMU 1999]

A)            NAND

B)            XOR                                         

C)            OR  

D)            None of these

Correct Answer: B

Solution :

                   \[Y=(A+B).\overline{AB}\] The given output equation can also be written as \[Y=(A+B).(\bar{A}+\bar{B})\]   (De morgan?s theorem) \[=A\bar{A}+A\bar{B}+B\bar{A}+B\bar{B}=0+A\bar{B}+\bar{A}B+0=\bar{A}B+A\bar{B}\] This is the expression for XOR gate.