555 Timer Weekend Projects - Make:

555 Timer IC Working, Pin Diagram, Examples (Astable, Monostable, Bistable)

DIY Electric Piano Circuit using 555 timer IC

555-Based Square-Wave And Triangle-Wave Function Generator Build For Beginners

555 Pulse Generator Module, How it Works | Arduino

555 Pulse Generator Module, How It Works

555 Timer Basics - Astable Mode

555 Timer Basics - Bistable Mode

555 Timer Basics - Monostable Mode