A lifelong analog EE, Dave has built and used many DC power supplies in his career. Well-known in the online engineering community, Dave makes some very good engineering content, like this video. It covers his work on a DIY Source-Measure Unit project, DIY-SMU, which is capable of 6 current ranges up to 100mA, and 3 voltage ranges up to +/- 150V. His project is open source and Arduino-based.
As a lifelong analog EE, I have built and used many DC power supplies starting with an LM309 5V regulator in the late 60's. Then on to uA723s, various 3 terminal linears, and many switchers. At Analogic in the late nineties I got to work on Semiconductor ATE equipment. One extreme was the AN/DP8200 VoltBox, a precision 20 bit voltage standard. I was exposed to low power SMUs for semiconductor testing. Then at Teradyne I was an analog EE in their DC instruments group, where we designed serious VIs (voltage-current instrument), DPSs (Device Power Supply) and SMUs for semiconductor and system testing. I have built various DC loads up to 20A, and LED testers up to 50A and 50V. I built a 4 quadrant power-supply and load (PS-Load). Not to mention my many audio amplifiers and Thermo-electric cooler (TEC) controls. I set up the PowerOne hackers blog.