They all work to some extent. They're output is really low so I had to crank up the gain on my mixer to hear them.
These are all the modules I could find and they seem to be a complete set. Almost all modules have an input and output for signal flow. The "Electronic switch" is a slow amplitude modulator. You can adjust the pulse width of the modulation with a knob. It's hard to read it but the top right one is a white noise generator.
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There are 2 oscillators: A square wave generator and a tri wave generator. Each functioned the same way: you flip it on, the button can complete the circuit if its off, and then it will turn on, and you can control the frequency of the oscillator on a very large scale with a pot. It has two settings: High and Low, for pitch. This is the triangle wave generator:
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The inside of each module is pretty simple; a tiny circuit board with a chip on it protected by a little piece of styrofoam. The envelope generators' insides are more complex but it doesn't work very well.
I can post some mp3s if enough people really want me to but they're annoying to set up because I don't have enough 9v batteries and patch/audio cables, and after all, they're very basic.
But anyways, they're interesting little boxes.