NOT operation simply gives opposite logic state of its input logic state. i.e. if input logic is 1 output will be 0 and vice versa. Not operation is also known as inversion or complementation.
NOT operation for variable A is expressed as:
It is read as ‘x equals NOT A’. It is also known as inverse/complement of A. There is another important point to note, in many cases instead of overbar, you will see use of prime (‘) symbol like below:
NOT operation is performed using NOT gate which can be constructed using diodes and transistors. To Know about NOT gate please see NOT gate section.