This circuit was obtained in a Motorola documentation from 1968. The circuit uses a power transistor of the time. Modern equivalents according to the load current and voltage can be used.
We found this circuit in a Popular Electronics of the 90s. The circuit still uses light bulbs, but...
This circuit is from Linear Technology 2005 documentation. The circuit is based on company...
The integrated circuit used in this power supply is no longer very common in power supplies today....