This circuit with unijunction transistors was found in a documentation from the 80's. The trigger times of the SCRs depend on the capacitors and are adjusted in the 5M (4M7) potentiometers.
This configuration can be found in other articles on this site. This was obtained in 1998...
This circuit generates both white and pink noise. The transistors can be BC548 and the power...
Found in 90s Radio Electronics, this shield can control high voltage loads in the power grid....