1. The problem statement, all variables and given/known data I know how to deal with resistors/capacitors etc in series and parallell circuits, but when it comes to more complex circuits I have no idea how to treat them, and I cant find any guides or info on it and my physics book doesnt tell anything. All solutions to this kind of problems never explain how to think. Heres a picture on a "normal" parallell circuit that is easy to understand: http://sv.wikipedia.org/wiki/Parallellkoppling What I dont understand, is how to treat more advanced circuits when its not trivial if its parallell or a serie. I give some examples of these kind of problems that I dont understand: 1. (see picture namnlös4) You have 12 1-ohm resistors set up in a cube. What resistance will you get if you measure at the ends over the cubes diagonal? 2. I just cant see how they get the total resistance in this figure (pic circ.jpg) 2. Relevant equations Serie circuits: Rtot=R1+R2+...+Rn parallell circuits: 1/Rtot=1/R1+1/R2+...+1/Rn 3. Given solutions to the problems 1. (see picture sol1) well I just cant see how they get to that calculation... 2.also see picture circ.jpg the problem that I dont understand in this one is how the deal with the resistors R3 and R5. I hope it didnt get too messy. Basically my problem is tips or "formulas" on how to deal with more complex electric circuits.