Question

The following arrangement performs the logic function of _________ gate.

All the gates present above are NAND gate.

• A. AND
• B. OR
• C. NAND
• D. EXOR

Answer 1

The correct option is B OR

The all gates given in the circuit are $NAND$ gate. So the output of left side gates will be $\overline{A}$ and $\overline{B}$.

The output of right side gate will be: $Y=\overline{\overline{A}.\overline{B}}=\overline{\overline{A}}+\overline{\overline{B}}=A+B$ (using de Morgan's law)

We know that the output of $OR$ gate for two inputs $A$ and $B$ is also $A+B$.