Using an NPN Transistor to Build a NOT Gate on a Breadboard

This short video shows how you can easily build a NOT gate on a breadboard using discrete electronic components. Here, we switch a BC547 NPN transistor on and off to control whether an LED is illuminated or not. When the switch, S1, is open, the LED is ON. When the switch is closed, the LED is OFF.
If you don't have a BC547 transistor to hand, just use a different NPN BJT with similar specs.

[@alf-qq1ou]

I like what you're doing here. Please feel encouraged to add more narration on the breadboard sections, for example why you used the resistors you did and why that affects where the current goes.