We found this circuit in a Radio Electronics from December 1963. The circuit combines valves and transistors and has a high input resistance. The circuit is powered by two batteries.
This circuit was published in a 1979 magazine, but it can still be easily assembled as the...
This transmitter for the 6-meter (50 MHz) radio-amateurs range was found in a publication from the...
Found in a Philips' 1968 documentation, this circuit is slightly different from the previous one. The...