I know that for identical batteries in parallel, the total voltage remains unchanged. However, what would happen if you connect batteries of different voltages in parallel?
As an example, could someone walk me through how you would find the potential at points A, B, C, D & E in the following diagram:
Best Answer
Your batteries are not "in parallel". Each has a resistor in series with it (R2 and R4). Also, all 5 points A,B,C,D, E are at the same potential because they are connected to each other (as well as to the negative poles of the batteries) with short circuits.
If you consider the negative pole of a battery to be at 0 V then the voltage at points A,B,C,D and E is also 0 V.
Note that the potential at a point is always a relative measure: it is always measured with reference to another point. As your circuit is "floating" (not connected to ground), you can assume any point of your circuit to be the reference point from which other voltages are measured. Because of that, the voltage at your points A,B,C,D,E can be any value you like - as long as you pick a suitable reference point. However, the negative pole of the batteries is the most logical point; hence your values are all 0 V.
Below I have redrawn your circuit to illustrate my points, assuming the negative pole of the battery is ground.