This circuit was obtained from an American technical manual from the 80's. The integrated circuit is an operational of the time that can be replaced by a modern equivalent.
This 1995 circuit uses an audio amplifier that is no longer common today. However, other...
The tone produced by this circuit attract fishes. The circuit is installed into a small can and...
This circuit is from Mullard 1969 documentation. The circuit operates at a relatively high supply...