Blinky! Reverse Avalanche Oscillators

Blinky! is 20 BC337 transistors oscillating in Reverse Avalanche mode. High values of components make slowly flashing random lights. How slow can you go? Low values of components can oscillate in the audio frequency range (20Hz-20kHz) and above.

Blinky! is a simple schematic repeated 20 times with a power input and an audio output. The Transistors begin to Avalanche at around 12V and the oscillating circuit uses between 15mA and 300mA depending on component choices. R1 on any individual Blink can be replaced with a light dependent resistor (LDR) for interesting cascading effects.

Blinky! Schematic

Download the BC337 transistor datasheet here.

Blinky! PCB

You can wire Blinky! up as an audio drone….If you have an individual Blink that is just on, it is oscillating so fast that you can’t see it, anything more than 50Hz is not visible to the naked eye. Test it with an Oscilloscope or the Audio Amplifier probe. You can then send this Audio signal to the Sum bus at the top of the PCB by soldering on the appropriate resistor. What random soundscapes could occur? If you hook the audio-frequency oscillator up to an LDR, it gets modulated by all the flashing LEDs around it!

Back to the Courses page.