I'm having a little trouble understanding this worked solution.
My understanding of superposition is that we "turn off" every independent power source except the one we plan on analysing, then we superimpose all the individual results to get the real result. But it's in the nodal analysis when we leave the current source on and turn the others off that's getting me.
The solution implies two node voltages when to me there are 3 junctions/nodes. They seem to just follow the current through the 8 ohm and the leftmost 4 ohm resistors all the way to the ground. Is this because there is no branch between the ground node and the other node voltages?
Also, is there a reason other than time saving that we use mesh analysis for the voltage sources and node analysis for the current source?
Sorry for all the questions, but when we remove the current source, I've never understood how the remaining open circuit works. Do we simply disregard the wires that remain in figure (b)? If yes, why do they leave it there?
One last thing I am little shaky on choosing at which junction the make a reference node, is there a reason the solution chose the one it did?
Thanks so much!