If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off.
Why it is not reading 0? I believe it's due to internal impedance of the power bench and surely accuracy of the bench is limited (technical spec says program accuracy is V: ±[0.5% of reading+2digits]）- but, for channel being off shouldn't I read 0V?
When I apply voltage I still see difference between what power bench displays and what multimeter reads, though I am more happy with that as it gets smaller with voltage increasing (for 1V and 5V diff is 6mV). But diff is different for positive voltage (+6mV) and for 0 (-15mV).
I am experimenting with transistors, therefore I would like to get good accuracy for voltage/current. Ultimately I will trust my multimeter but would like to understand what I am working with.