We found this circuit in a publication by General Electric in the 1980s. The transistors and the PUT are from that time. The control is done by a tachometer based on an optical coupler.
We found this circuit in a documentation for 1977 American radio amateurs. The LM336 integrated circuit...
The frequency of this oscillator depends on the coil and the 10 nF capacitor. The circuit is from...
This circuit can work with the previous one generating signals, that can be decoded by it. The...