A teardown of the Keithley 2231A303 power supply, which reveals some interesting little details.

Note that my concern about the accuracy was unfounded the PWM for the set point generation is in fact supplied from a good voltage reference (hence the buffer). More on that in this video:    • Keithley 2231A303 Power Supply WrapUp  

Apart from that, I have some more on this power supply on my web site: http://kitsunedenshi.net/equipment:k....