Found in 1965 Delco Radio documentation, this circuit uses transistors from that era. Modern equivalents can be used. The characteristics of the inductor were not given.
This circuit serves to isolate analog signals, for example, audio signals in a secure link...
This circuit uses a 7812 and another regulator integrated circuit that is not very common...
This is the normal configuration of the LM12 as a high voltage amplifier. The LM12 consists of a...