Question

A NOR gate and a NAND gate are connected as shown in the figure. Two different sets of inputs are given to this setup. In the first case, the inputs to the gates are $A=0,B=0,C=0$. In the second case, the inputs are $A=1,B=0,C=1$. The output $D$ in the first case and second case respectively are:

• A. $0$ and $0$
• B. $0$ and $1$
• C. $1$ and $0$
• D. $1$ and $1$

Answer 1

The correct option is D $1$ and $1$

In first case $A=0,B=0$
$\therefore$ Output of NOR gate, $Y=\overline{A+B}=1$
This output is the input for NAND gate ie, $Y=1$ and $C=0$
$\therefore$ $D=\overline{Y.C}=1$
In second case $A=1,B=0$
$\therefore$ Output of NOR Gate, $Y=\overline{A+B}=0$
This output is the input for NAND gate ie $Y=0$ and $C=1$
$\therefore$ $D=\overline{Y.C}=1$