How many input lines are there in the NOT gate ?

A NOT gate, also known as an inverter, is a fundamental digital logic gate that implements logical negation. It is unique among basic logic gates because it is a unary operator, meaning it operates on only one variable.

A NOT gate has exactly one input and one output. Its function is to reverse the logical state of the input signal: if the input is high (logic 1), the output is low (logic 0); conversely, if the input is low (logic 0), the output is high (logic 1). In contrast, other basic gates like AND, OR, NAND, and NOR typically require two or more input lines to perform their respective logical operations.