I need to monitor a differential voltage of up to 150mV between two points, each elevated less than +1 volt from the common negative of a 5 volt supply.
I think I can use an el cheapo 3.5 digit panel meter module (like Jaycar QP5570 or Dick Smith Q2220), which I assume have a common input offset to allow +/- measurements relative to the supply common. However, the information provided is very sparse, and I wonder if anyone has details of the input arrangements of this and similar modules, and their nasty surprises.
All the best Ian Macmillan