An Inverter or less commonly, a NOT gate, is a logic gate which implements logical negation. When the input is LOW, the output is HIGH and when the input is HIGH, the output is LOW. Inverters are the nucleus of all digital systems. Understanding its operation, behavior, and properties for a specific processor makes it possible to expand its design onto more complex structures such as NOR and NAND gates. The electrical behavior of much bigger and complex circuitry can be derived by extrapolating the behavior observed from simple inverters.

Functionality

NOT Gate
A	Q
0	1
1	0

An inverter generates a signal that is logically opposite to its input. When the input is sufficiently LOW, the output generate is HIGH. Likewise, when the input is sufficiently HIGH, the output generate becomes LOW.

Expression:

Q = A = ¬A

Implementation

An inverter can be implemented using various transistor technologies.