Question

Identify the operation performed by the circuit given below.

• A. NOT
• B. OR
• C. AND
• D. NAND

Answer 1

The correct option is C

AND

Step 1: Given diagram:

AND: The AND gate implements the logical conjunction from mathematical logic; it operates in accordance with the preceding truth table. If all of the inputs to the AND gate are HIGH, just a HIGH output (1) is produced (1). If the AND gate's inputs are not all HIGH, the output will be LOW.

Step 2: Draw the required diagram,

Now apply the Boolean algebra,

Step 3: Therefore the equation,

For NOR gate 1 ( with input A) . the output will be

$$\begin{gathered} Y=\overline{A+A} \\ Y=\overline{A} \end{gathered}$$

For NOR gate 2 ( with input B) . the output will be

$$\begin{gathered} Y=\overline{B+B} \\ Y=\overline{B} \end{gathered}$$

For NOR gate 3 ( with input C) . the output will be

$$\begin{gathered} Y=\overline{C+C} \\ Y=\overline{C} \end{gathered}$$

For NOR gate 4 ( with input of all other three NOR gate) . the output will be

$$\begin{gathered} Y=\overline{\overline{A}+\overline{B}+\overline{C}} \\ Y=\overline{\overline{A}}·\overline{\overline{B}}·\overline{\overline{C}} \end{gathered}$$

Now use the de- Morgan theorem,

Therefore,

$Y=A·B·C$

Then this system behaves like an AND gate.

Hence, the correct option is (C).