We find this circuit in American documentation from the 1980s. It consists of a frequency folder using a varicap. The capacitors and coils depend on the frequency of operation.
It is like to the previous circuit with a lock that keeps the LED on at the end of the timer. The...
We found this circuit in an 80's Electronic Design. The circuit uses an integrated of the time....
This loop antenna was found in a 1990s documentation. The circuit includes a field strength meter. The...