Found in an 1989 R-E Experimenters Handbook, this circuit produces several sound effects that can be modified. The signal must be applied to an external amplifier.
This circuit with a component from the time was found in the Radio Electronics magazine of...
Using two LM377s, this amplifier provides a few watts of audio in a low impedance speaker and the power...
This circuit is from 2005 documentation. It automatically starts an irrigation pump when the...