Could anyone please describe how the attached circuit works. Thanks Hero 99 for replying to part of circuit earlier.
In short the circuit controls a generator at 450 Volts. It senses the O/P and rectifies it down to 14V. The circuit controls the Exciter Field by varying load resistor R28.
If anyone could enter a detailed description, I would be grateful. I'm fairly happy with the transistor part of the diagram ie V18,19,20,23 but not how V21 works.
Thank you for any assistance