This circuit generates a siren sound. It was found in the April 1969 Radio Electronics magazine. The output signal is to be applied to an external amplifier.
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...