Which of the following gate is called universal gate

Options

A. OR
B. AND
C. NAND
D. NOT

Answer

To determine which gate is called a universal gate, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Universal Gates**:
A universal gate is a type of logic gate that can be used to implement any Boolean function without needing to use any other gate type. The two most common universal gates are NAND and NOR.

2. **Identify Fundamental Gates**:
The fundamental gates in digital logic are AND, OR, and NOT gates. These gates are the building blocks for creating more complex logic circuits.

3. **Check the Properties of NAND Gate**:
The NAND gate is a universal gate because:
- It can be used to create an AND gate:
- By connecting the output of a NAND gate to a NOT gate (inverter), we can achieve the AND function.
- It can also create an OR gate:
- By using De Morgan's theorem, we can express OR using NAND gates.
- It can create a NOT gate:
- A single NAND gate can function as a NOT gate by connecting both inputs to the same signal.

4. **Check the Properties of NOR Gate**:
Similarly, the NOR gate is also a universal gate because:
- It can create an OR gate by inverting the output.
- It can create an AND gate using De Morgan's theorem.
- It can create a NOT gate by connecting both inputs to the same signal.

5. **Conclusion**:
Since both NAND and NOR gates can be used to derive all fundamental gates, they are both considered universal gates. However, if the question specifies a single answer, it is often accepted that the NAND gate is the most commonly referred universal gate.

### Final Answer:
The correct answer is the **NAND gate**.

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