Suggested by a 1968 documentation, this circuit limits the current of a regulator and can be adapted to other currents. The transistors are from the era.
This traditional doubler configuration with the 555 IC can be found in other articles on the...
This circuit is from an 80's component manual. The components are from the time, but the circuit...
This circuit for the 3.5 MHz band (80 meters) was found in an old radio amateur documentation. The circuit...