In this project I revise the classic one transistor negative resistance relaxation oscillator to allow us to flash colour changing LEDs. This involves both using the common BC547 backwards, and running the colour changing LEDs ridiculously out of spec. Crucially, however, it works!

To see this example of dual-action component abuse, skip to 12:14.

To allow the LED to maintain it's colour state, I have carefully selected the component values to create a voltage divider that provides enough power to both maintain the state in the LED's built-in controller, but also allow the BC547 transistor to enter and exit its negative resistance state.

This project was inspired by the following projects and resources.