Which of the following gate is called universal gate?

Explanation:

Universal Gate

Definition: A universal gate is a type of logic gate that can be used to implement any Boolean function without needing to use any other type of gate. Universal gates are versatile and are fundamental in digital electronics because they can be used to construct other basic gates such as AND, OR, and NOT gates.

Correct Option: The correct answer is Option 3: NOR Gate.

Explanation:

The NOR gate is called a universal gate because it can be used to create all the other basic logic gates (AND, OR, NOT, NAND, and XOR). The NOR gate is a combination of the OR gate followed by a NOT gate. It outputs a logical "1" only when all inputs are logical "0". The truth table for a NOR gate is as follows:

Why NOR Gate is Universal:

• Implementation of NOT Gate: A single input NOR gate acts as a NOT gate. If the input is "A", the output will be "NOT A".
• Implementation of OR Gate: By combining two NOR gates, an OR gate can be constructed.
• Implementation of AND Gate: By using multiple NOR gates in a specific configuration, an AND gate can be created.
• Implementation of XOR Gate: XOR gates can also be constructed using NOR gates, but it requires a more complex arrangement.

Because of its ability to replicate all other logic gates, the NOR gate is classified as a universal gate. This feature is extremely useful in digital circuit design, as it allows for simplification and standardization in hardware implementations.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: AND Gate

The AND gate is a basic logic gate that outputs "1" only when all its inputs are "1". It is not a universal gate because it cannot be used to construct other gates by itself. While it is a fundamental gate in digital circuits, it lacks the versatility of universal gates like NOR and NAND.

Option 2: NOT Gate

The NOT gate is a unary operator that outputs the inverse of its input. While it is essential for negation in digital logic, it is not a universal gate. It cannot construct other gates without additional components.

Option 4: EX-OR Gate

The XOR gate outputs "1" when its inputs are different. Although it has unique properties and is widely used in applications like parity checking and error detection, it is not a universal gate. It cannot be used to construct other gates independently.

Option 5: NAND Gate

Although not listed as the correct answer in the question, the NAND gate is also a universal gate. Like the NOR gate, it can be used to construct all other basic logic gates, making it equally versatile. If the question had included NAND gate as an option, it would also have been correct.

Conclusion:

The NOR gate is a universal gate because it can be used to implement any Boolean function and construct all other basic logic gates. This versatility makes it essential in digital electronics and circuit design. While other gates like AND, NOT, and XOR serve specific purposes, they lack the ability to replicate all other gate functions, which is the defining characteristic of universal gates. Alongside NOR gates, NAND gates also share the universal gate classification.