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.
This SCR relaxation oscillator was found in an 80's Electronic Design. It flashes a small...
We found this circuit in a 1982 publication. This source allows an adjustment of the output...
This interesting circuit was obtained from a Poptronics of February 2001. The American magazine no...