This power supply is based on the 723 integrated circuit, which is no longer very common today. The transistor must have a heatsink and the bridge can be formed by diodes 1N4002 or equivalent.
This circuit is used in transceivers, enabling input selection by diode switching through polarity...
This configuration was found in an American publication from the 90s. Operators admit equivalents just...
This circuit was found in an Italian magazine Elettronica Prática of 1977. The transistors can be...