1: But I don't see any nodes in the "TwoNodes_01" drawing. Help me, please.
Oh... so what do you call (a) and (b) in all figures?
2: This is confusing me since I started this thread. I would try to ask it now and try my best to convey my confusion. Please have a look on the following link:
https://img708.imageshack.us/img708/3581/img0002ri.jpg
Who told you that a current SHOULD always go in one direction according to the node potentials; that is from a high/low potential to a low/high one?! :wink:
First we need to distinguish between the direction of a current inside an electrical element and outside of it.
Let us analyse a voltage source connected to a resistor. The current inside the voltage source is from a low potential to a high potential (this means it is a generator). The current outside of it is from high to low instead, passing in the resistor (so the resistor is a load, consuming power).
Also we need to distinguish between an assumed direction of a current and its final real direction which is based on the sign of the assumed one (as a given data or a result).
Finally if we assume that a current is said to be positive when it goes from terminal of a high potential to the terminal of the lower one, we may add:
A device is said to be a generator if the product of its voltage and current is negative, otherwise it is a receptor (as a resistor).
It is about signs... when writing equations we need to forget what the real values of the voltages and currents are. Instead we have to focus on the assumed directions (as positive) and the formulas we need to apply to get an equation (or equations). After getting the results (and their signs) only, we may like to discuss what is real happening in the circuit based on the results.
I think the
best remedy for your confusion (I usually apply it on myself)... is to forget completely all about it and keep learning other things then rethink of it again after a while from the start... you will amaze yourself when everything will be clear to you even without getting help from anyone.