1. The problem statement, all variables and given/known data This isn't so much of a problem itself but I found it interesting that on the All About Circuits website, two of the questions give a phase angle for impedance as opposite the angle of current. I understand the current is 90 degrees out of phase with voltage in both RL and RC circuits, but do not understand the reasoning behind the impedance phase angles. Here are the relevant links, http://www.allaboutcircuits.com/tex...nt/chpt-4/series-resistor-capacitor-circuits/ http://www.allaboutcircuits.com/tex...ent/chpt-3/series-resistor-inductor-circuits/ 2. Relevant equations V = IR 3. The attempt at a solution Not sure how to attempt a solution here, I looked online and used various searches but didn't find anything. If anyone could shed some light on this it would be appreciated.