The LM3909 tone generator integrated circuit of this application is uncommon nowadays. The circuit can operate on a single battery and is very sensitive.
This configuration, found in many publications, is from an American book from 1981. The power...
The circuit shown is from an American publication from 1970. It produces a tone that attracts fish...
Found a documentation on PCs from 1996, this circuit can be used as a shield. The relay is rated at...