Question

For the given circuit, which of the mentioned below input will give output as 1.

• A. P = 0 ; Q = 0
• B. P = 1 ; Q = 0
• C. P = 0 ; Q = 1
• D. Either P = 1 or Q = 1

Answer 1

The correct option is C P = 0 ; Q = 1

$S=[\overline{(P+Q)}+\overline{(P+(P+Q\left)\right)}]\overline{(P+(P+Q\left)\right)}$

Considering, $\overline{P+Q}=Xand\overline{P+\left(\overline{P+Q}\right)}=Y$

Then, $S=(X+Y)Y=XY+Y=Y$

$S=\overline{P+\left(\overline{P+Q}\right)}=\overline{P}.(P+Q)=\overline{P}Q$

So far, S = 1, P = 0, Q = 1