Question

For which one of the following input combinations, the given logic circuit gives the output $Y=1$?

• A. $A=0,B=0,C=0$
• B. $A=0,B=1,C=0$
• C. $A=0,B=1,C=1$
• D. $A=1,B=1,C=1$
• E. $A=1,B=0,C=1$

Answer 1

The correct option is C $A=0,B=1,C=1$

The logic circuit is
The output,
$Y=\overline{\overline{\overline{A}\cdot B}+\overline{C}}=\overline{\overline{\overline{A}\cdot B}\cdot \overline{C}}=\overline{A}\cdot B\cdot C$
$[\overline{A+B}=\overline{A}\cdot \overline{B}$, Demorgan's law]
when $A=0,B=1,C=1$, then $Y=1[\because \overline{A}=1]$.