This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times of several days or even weeks can be achieved depending on the value of C1.
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...