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.
The output current of this circuit reaches 12 mA. The zener diode determines the output voltage. The...
Found in Maxim's documentation from the 90's, this circuit uses an integrated from the time...
Found in a 1980s documentation, this circuit makes use of components from that time. Modern...