This filter was found in an 80's English publication. However, it can be implemented with modern operating systems. The circuit can tune frequencies in a range from 10,000 to 1.
The circuit shown in the figure shuts off a load when the voltage drops below the value determined...
This circuit was found in an American documentation from 1969. It serves to trigger circuits by...
We found this circuit in an American 1980s documentation. Other comparators can be used and the...