1. Do the polarities of the sources in Figure 14.1 matter as to the resulting voltages? Will the magnitudes of the voltages be the same if one or both sources have an inverted polarity?
2. In both circuits of this exercise the negative terminals of the sources are connected to the ground. Is this a requirement for nodal analysis? What would happen to the node voltages if the positions of E1 and R1 in Figure 14.1 were swapped?

 

A R1 R2 R3 El E2 Figure 14.1 A B R4 R1 R2 R3 R5 E1 E2 Figure 14.2