A few months ago I decided to catalog a bunch of the simple, little toy circuits I had collected.
I set up a little testing station and started removing the circuits from the toys. As I went, I took notes on the voltage rating, pitch adjustment settings, trigger points and any other details that would aid me in easily adapting these circuits into future projects. Then I numbered each circuit, labeled all the different points on the circuit board, recorded its sounds, stripped it down and filed it away.
The following samples are the sounds I recorded from each circuit. All of them were recorded with a mic, so the sound quality is lacking on some of them, but they still give a good indication of what the circuit does and how the pitch adjustment sounds.