The NOT Gate

The NOT gate is the simplest of all logic gates. It has a single input and a single output, and its job is to invert (reverse) whatever value it receives. If the input is 1, the output is 0. If the input is 0, the output is 1.

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How the NOT Gate Works

The NOT gate performs the Boolean operation of negation (also called inversion or complementation). It takes one input and produces the opposite value as its output.

• If the input is 1 (TRUE), the output is 0 (FALSE).
• If the input is 0 (FALSE), the output is 1 (TRUE).

Think of the NOT gate as a simple "flip" — it always gives you the opposite of what you put in.

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Truth Table for NOT

The truth table for a NOT gate is the simplest of all logic gates because there is only one input:

Input (A)	Output (¬A)
0	1
1	0