We found this circuit in the June 1992 issue of Radio Electronics magazine. The sensor is a common diode. The circuit is powered by the power grid from a 12 V transformer.
This circuit was found in a 90s American documentation. The circuit uses still common components...
We found this configuration in a Radio Shack documentation from 1977. Here we have the way to...
This circuit was obtained from an American documentation from 1976. The circuit has a dynamic...