Here is a figure from my text and I am wondering if this is a mistake:
Now, what is going on at Node A? I was always shown that the current flows from + to - through an element of a circuit. When you look at the elements connected to A, element AB has the current flowing from + to - and the element FA has it from - to +. More importantly, how can elements AB and FA have the polarities shown?
I won't even get into Node C until I figure out what is happening at A.