This circuit was found in American documentation from the 90's. The transformer determines the output voltage. The transistor must be equipped with a heat sink.
Books and e-Books by Institute NCB 100 CIRCUITS - SHIELDS FOR ARDUINO FUN PROJECTS FOR THE...
This circuit is from 70's documentation. The output transistors can be BC548 and BC549. The driver...
The LM109 was manufactured by many semiconductor companies that presented different configurations in their...