In the below circuit, X = ?

• A. A + B
• B. B
• C. A
• D. A.B

Answer: (D)

The circuit shown in the question is an AND GATE. In an AND gate has two or more inputs but it has only one output. An input signal applied to a gate has only two stable states, either 1 (HIGH) or 0 (LOW). In AND gate for any input A&B the output is A.B.