Identify the logic operation carried out by the following circuit.

• A

  AND
• B

  NAND
• C

  NOR
• Correct answer
  D

  OR

Solution

Using Boolean law \( A \times A=A \), we get
\( \overline{A \cdot A}=\bar{A} \) and \( \overline{B \cdot B}=\bar{B} \)
By de Morgan's law, we have
\[ \begin{array}{l} \bar{A} \cdot \bar{B}=\overline{\bar{A}}+\overline{\bar{B}}=A+B \\ \Rightarrow Y=A+B \end{array} \]
Therefore, logic operation carried by the given circuit is OR.

Hence, the correct answer is option: 'D'.