Found in American documentation from the 90's, this circuit is very current and can be implemented with transistors of general use. Never use a power supply without a transformer.
This circuit was obtained in a 1975 documentation. It is intended for old vehicles that still use...
With this circuit it is possible to select transistors and their compliant test. Or circuit...
This power supply circuit with selectable voltages was found in the June 1979 issue of Radio...