Close

Astable Multivibrator for PWM

A project log for Light Sensitive Kinetic Sculpture Tribute To Dad

A kinetic sculpture that reacts to light and shadow, constructed mostly from components my late father had recycled from other electronics

bornachbornach 01/06/2019 at 17:410 Comments

I like making these oscillators from discrete components. I have the circuit memorised. They can easily be modified to trigger some other circuit periodically.

This is what it looks like soldered without using a circuit board:

I had to resort to adding an extra connecting wire. I didn't want it to end up looking like the tight cluster of the Schmitt trigger since I would need easy access to the collector of one of the transistors when implementing the Pulse Width Modulation.

As an aside - I once used a boardboard version of the multivibrator to drive the percussion inputs to a Casio MT-205.

The plan here is to do something similar with an H-bridge to reduce the speed of the DC motor. I've chosen the resistor and capacitors to oscillate at tens of cycles per second and to give a duty cycle of just about 40%

Discussions