This simple rain, leak or moisture detector circuit appears in other places on this site with slight variations. This was obtained in an English documentation from the 70s.
Using the LM3909 this circuit was found in the January 1992 issue of Radio Electronics magazine....
This circuit allows the coding of several relays from coded keys that must be activated, according to...
To power small projects, we found this circuit in the Radio Electronics magazine of May 1977. The...