Question

Describe the operation of a NOR gate and its truth table.

Answer 1

A NOR gate (NOT OR gate) is a fundamental logic gate that performs a logical NOR operation. It has two or more inputs and one output. The output of a NOR gate is true (logic 1) only when all of its inputs are false (logic 0). In other words, if any of the inputs are true, the output will be false.

The NOR gate is represented by the symbol ⊼ or sometimes by the symbol OR with a small circle at the end of the arc, indicating the negation. The number of inputs can vary, but we will consider a NOR gate with two inputs, A and B, for this explanation.

Truth table for a 2-input NOR gate:

Input A    Input B    Output
0    0    1
0    1    0
1    0    0
1    1    0

In the truth table:

When both Input A and Input B are 0, the output is 1 (true).
When either Input A or Input B or both are 1, the output is 0 (false).

The logic can be represented as: Output = ¬(A OR B), where ¬ denotes the NOT operation. In other words, the output of the NOR gate is the negation of the OR operation of its inputs.

NOR gates are used in digital circuits for various applications, such as creating logic functions like NAND, XOR, XNOR, and more. They are fundamental building blocks in digital circuit design and play a crucial role in constructing more complex logical operations.