This high sensitivity circuit was found in the July 1992 Radio Electronics magazine. The circuit drives a buzzer, but a relay can be used to activate an external load.
The circuit presented was obtained from a 1976 Italian Radio Elettronica but can be easily...
This voltage amplifier with operational amplifier was found in an old documentation. However, it can...
This filter was obtained from Radio Electronics from the 80's. The configuration applies to any...