I have the following circuit diagram that I've added labels for the internal nodes to using outside sources. I understand what an internal node is, however what I'm confused about is-- for example-- E1 has 2 wires connected to another circuit element, so they're both internal nodes, but how do I distinguish which is
n1? Or is this completely arbitrary?
And why is
n2 after E4 here, is it because it has to follow the flow of the circuit?