Problem 1.1    Source:  Problem developed by the author of the site.

Calculate the current that passes through the resistance R in the circuit in Figura 01-01.1.

Problem 1.2    Source:   Problem developed by the author of the site.

Calculate the resulting voltage on the R resistor in the font association of the diagram shown on Figura 01-02.1.

This problem has a very simple solution because just add algebraically the voltages of the sources following the signals that are next to them. By running the mesh counter-clockwise starting at point b and passing through point a, we have:

In this case, the negative signal indicates that point b is more positive than point a. Thus, the current circulates through the resistor in the direction of point b to point a.