The following image shows my connections:
The grounds of all devices are connected to a common PCB. When I measure the 1.2V referenced to the ground on my PCB, it reads 1.201V which is great. But when referenced to the common GND PCB, it increases by 23mV, I expected it to be lower than 1.201V (because of bigger ground loop, therefore more voltage drop) not higher, how come?!
Edit #1 : Notes
- I have only ONE voltmeter used for both measurements, sorry it's not clear in the image.
- "My PCB" is supplied by 64V from the shown power supply, then it's converted to 12V then to 1.2V
Edit #2 : More Notes
These measurements are the same even before I soldered the rest of the board. I solder power modules first of all, even before a load exists I got these results!
The "common PCB" is a one layer board that is only used as a common ground. It has no ICs or passive components. Only copper pour and holes for crocodiles to be attached.