This circuit was found in a documentation of the 80s, having didactic purpose. For R1 values between 10k to 1M can be used. Transistors are general purpose types.
We found this circuit in an old documentation from the 70s, but it can be assembled with modern...
Found in the January 1992 issue of Radio Electronics magazine, this circuit has its frequency...
This circuit was found in a NASA documentation from the 1980s. The components used are of the time...