Question

A $NOR$ gate and a $NAND$ gate are connected as shown in the figure. Two different sets of inputs are given to this set up. In the first case, the input 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

Answer: (D)

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, i.e., $Y=1$ and
$C=0$
$\therefore D=\overline{Y \cdot C}=1$
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 i.e., $Y=0$ and $C=1$
$\therefore D=\overline{Y \cdot C}=1$