NOT Gate (Inverter)

Truth table for a NOT gate

Input	Output
false	true
true	false

A NOT gate, often called an inverter, is a nice digital logic gate to start with because it has only a single input with simple behavior. A NOT gate performs logical negation on its input. In other words, if the input is true, then the output will be false. Similarly, a false input results in a true output.

The truth table for a NOT gate appears to the right.

Symbols

Each of the symbols below can be used to represent a NOT gate. There are multiple international standards defined, and one may preferred over the other in your region of the world.

ASNI / IEEE	IEC

Live Example

Try the following interactive example to see for yourself how a NOT gate behaves.

Further Reading

To learn more, check out the following external resources:

• Inverter (logic gate) on Wikipedia

• The NOT gate on All About Circuits

• Basic Logical Functions and Gates at Play-Hookey

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