The NOT gate is a logic with inverting function, with which the logical negation is performed. It is an inverter that inverts the logic state of input "e" so that the output has the corresponding inverted logic level. The ground is connected to the output.
For example, if the input of the NOT gate is "1", the output is "0", if the input is "0", the output is "1". The output of the NOT logic always has the opposite digital state of the input. The rise times and fall times of such an inverter circuit are asymmetrical. On the other hand, the input of the logic can also be equipped with an inverter function. This is indicated in the circuit by a small circle at the corresponding input.