This transistor tester with different gain ranges was found in documentation from the 1980s. The circuit can still be implemented with more modern components and used with general purpose transistors.
This is the receiver for the transmitter suggested in CIR13081. The configuration is old, and...
This circuit has a frequency control. We found it in a Radio Electronics from January 1965. The...
This circuit was found in an old American magazine for radio amateurs. The circuit is based on a...