This circuit appears in several versions in publications of the time and can be modified by changing the capacitors. This one is from Radio Electonics magazine from October 1992.
With the first project we present, a relay is activated in the presence of light. We can use it as...
The ZN414 is an uncommon integrated circuit currently used in the elaboration of very simple MW...
This circuit can be used to detect the signals from the previous circuit or from any radio...