Why do voltages in series add? I would like to have this explained physically. Most answers I get are something like: "Because in a parallel circuit the voltage is constant." I have memorized the concept but want to try and learn why this is so. What physically goes on with the circuit to make...
What does the operating temperature of a fuel cell mean? Is this the temperature the cell generates or the temperature the cell is brought to so that it can operate? I see articles that state operating temperatures for different fuel cell systems---i.e. solid oxide 600 to 1000 C, phosphoric acid...