This voltage-controlled oscillator was found in a 1965 Electronic Design. Transistors are from the time, and modern equivalents can be tested.
I found this circuit in a 1986 English magazine. It can still be easily assembled, exchanging Q1...
We found this circuit in an Argentine publication from the 70s. The coil can be made with 80 turns...
Found in General Electric documentation from 1967, this circuit makes use of an unusual...