This circuit was found in the July 1992 issue of Radio Electronics magazine. The circuit is based on a 741 that activates a buzzer with oscillator. R5 adjusts the sensitivity.
This frequency divider with SUS was found in General Electric's 1967 documentation. Similar...
The configuration of this circuit was suggested by an old English publication that comes to...
This two-input limit detector was found in an American 1980s documentation. The circuit can be...