We found this circuit with duty cycle adjustment in the May 1988 Radio Electronics magazine. The source must be symmetrical, and the frequency given by R3 and C1.
This configuration was obtained in a 1977 FET Databook. The circuit can be practically any JFET...
The integrated circuit used in this regulator is not very common today. The circuit is from old...
The operational used is uncommon today, but equivalents can be used. Unlike the previous one, this...