These cost almost nothing, so I bought a few and plan to use them on my Lab PSU. They have separate PSU and measurement cables – so initially I connected the PSU to the same PSU as I use – the result was that Voltage increased as Ampere increased. Realising the mistake I connected a separate PSU to power the meter and voila – the difference between my meter and multimeter is constant.
It shows that as I increase load and current the out voltage will drop ca 10mV from 0A to 4A – compared to the ZHAOXIN PSU this is great news. The meters above have calibration points on the back. The most important is that the way I mount them is guaranteed to show actual values out – not some fictional setting values.