Question

What does the following combination of gates produce?

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

Hint:

Two NOT gates feed a NOR followed by a NOT. Write the Boolean expression and use De Morgan's theorem.

Answer 1

The Correct Option is A

Step 1: Idea
NOR followed by NOT is the same as OR. So $G_3$ and $G_4$ together act as an OR gate.

Step 2: Inputs
The OR gate receives $\bar A$ and $\bar B$, so $Y=\bar A+\bar B$.

Step 3: Identify
$\bar A+\bar B$ is $0$ only when both $A$ and $B$ are $1$. That is the NAND function, option (A).

Final Answer:
The output is NAND. \[ \boxed{\text{NAND}} \]