Found in a Popular Electronics from the 90s, this circuit activates a recorder for automatic recording of telephone calls. The circuit was used with old cassette recorders of the time.
This xenon lamp circuit is from old documentation. The trip transformer has a 1: 1 turn ratio and...
This simple alarm with integrated CMOS sounds a piezoelectric transducer when the sensor circuit...
In the figure we have an interesting circuit for those with a project that requires a sub-multiple...