A NOT gate is also known as an Inverter as it inverts the signal from being a HIGH to LOW or from LOW to HIGH.
Below you will find the circuit schematics and list of parts for this setup, and also a video showing step by step how to build the circuit on breadboard.
Components list:
T1, T2 – BC547
R1 – 330Ω
R2 – 1KΩ
D1 – 1N4148
L1 – LED
Step by step video guide on how to build the circuit according to the schematic above: