This circuit was found in an Electronic Design. The circuit can be programmed to operate in different frequency ranges with the indicated characteristics. The IC component is uncommon today.
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...