The 40106 chip: change the timbre of a sound

In this exercise, we are going to use 2 of the 40106 chip’s 6 oscillators to make a sound whose ‘timbre’ we can change.

What is timbre?

Identify 3 sounds that have very different timbres.

How could you describe what a timbre is?

What you’ll need

  1. a breadboard
  2. a 40106 chip
  3. a 9V battery
  4. 2 capacitors (0.1 Microfarads, see here)
  5. a photoresistor
  6. a resistor
  7. a diode
  8. a potentiometer (log is best, A50K is good)
  9. another protentiometer (linear, B100K is good)
  10. a piezo (or an amplifier connected to speakers)

The breadboard diagram

This is what the circuit looks like when prototyped on a breadboard.


If you can read circuit diagrams, you can consult this image (thanks to Hackaday).

This is what the finished circuit looks like when put together:


Notice that in this diagram, there is an extra button (the little black thing). This button is used to stop the power going to the circuit. this way, the sound is only activated when the button is pressed. This is very useful when the sounds start to get a little irritating (which it will after listening to it for 10 minutes!).