Question

For the circuit shown in figure the Boolean expression for the output Y in terms of inputs P, Q, R and S is

• A. $\overline{P}+\overline{Q}+\overline{R}+\overline{S}$
• B. $(P+Q)(R+S)$
• C. $(\overline{P}+\overline{Q})+(\overline{R}+\overline{S})$
• D. $P+Q+R+S$

Answer 1

The correct option is D $P+Q+R+S$

$Y=\overline{(\overline{P}.\overline{Q}).(\overline{R}.\overline{S})}\because \overline{(\overline{A}.\overline{B})}=(A+B)$
$\therefore Y=\overline{\overline{P}.\overline{Q}}+\overline{\overline{R}.\overline{S}}$
$\Rightarrow Y=(P+Q+R+S)$