Question

Following circuit will act as:

• A. NOR gate
• B. NAND gate
• C. AND gate
• D. OR gate

Answer 1

Answer: (A)

output of gate 1 is, $y_1$ = $\bar{A}$

output of gate 2 is, $y_1$ = $\bar{B}$
Then the output of gate 3 is$\Rightarrow y_3=\overline{\bar{A}\bar{B}}$
= A + B
So the output of gate 4 is,
$y_4=\overline{\left(A+B\right).\left(A+B\right)}\Rightarrow \overline{A+B}$
So the circuit acts as a NOR Gate.