All about Linear Power Supplies

[Neomys Sapiens]

We discussed that upper/first circuit from MarkF somewhere in detail. It is deficient in terms of SOA protection of the power transistor. Yet I did build an extremely long-lived and robust power supply with it: replace the MJ4502 with the combination from the second circuit and then replace the TIP3055 with 5xLM395 in parallel (for 5A), which are self protecting power transistors.

[Neomys Sapiens]

Oh, and both do not extend down to zero volts. The first resembles a real lab power supply in that it has a constant current mode with a better defined set-on. You should get the original datasheet/appnote for the LMx17, because this is where they come from.