NOT gate
A  NOT gate (also often called Inverter) is a logic gate. Each NOT gate has only one input signal. Logically with NOT gates, the input and the output swap, so if you input 1 it outputs as 0; likewise if you input 0 it outputs as 1.The NOT gate negates the values of data or signal in its input. It will always output the opposite signal. Its main function is to interchange logic.