This simple sensitive circuit was suggested in a July 1992 Radio Electronics issue. The relay is a double-contact changeover relay. Sensitivity adjustment is made at R2.
The advantage of this circuit lies in the fact that it does not need a negative source to generate...
This simple audio generator with the 741 was found in a 90sTexas Instruments. The circuit...
With this circuit from an old 1973 publication it is possible to use a small speaker as a...