Hi, I have a question about grounding. Everything's relative right? Take two power supplies, each at 15+ DC and link one to the other (in series). Connecting to the circuit you will have a zero point (ground), a +15 VDC, and a -15 VDC. Reconfiguring the circuit and calling -15 VDC ground you will now have 0-30 VDC power source. Now take a different case. Two power supplies; +10 VDC and +5 VDC. Link them together in the same fasion (series). You now have a few options (without drop resistors for alterations)): 0-15 VDC -15-0 VDC, -5-+10 VDC, and so on. A particular IC (none specific, seems to happen to most); This IC needs a Vin of +5 VDC and a 'ground' point to operate. Theoretically one could have Vin as +10 Vdc and 'ground' +5 VDC, but i.f.f. any branches of circuits involved with that IC, and their child branches use +5 VDC as 'ground'. If for instance an entire circuit is powered this way, and the true ground (0 VDC) never sees the circuit, then the circuit always sees potential in reference to the 5 and 10 V potentials. This (or at least I think, maybe I'm wrong; correct me if so) means that the IC/circuit is seeing 0-5 VDC the same as a true ground and +5 VDC power source. Setting up and attempting multiple configurations and scenarios; I have seen that this is not true. What is wrong with this? It's obviously wrong or it would work; the problem is I don't understand why. If it matters: we are putting power to a DSPIC 33F6014A. Other IC's being used are Murata NMT0572SC. Any help would be greatly appreciated.