1. The problem statement, all variables and given/known data For the resistor network in the picture, use loop currents to find the current through the 4Ω resistor and the change in voltage E across the current source. Circuit Attached Below . 2. Relevant equations Kirchoffs Laws Loop Current Method V=IR 3. The attempt at a solution Firstly I divided the circuit into 3 loops with 3 currents. Top left Loop, Current A Top right Loop, Current B Bottom Loop, Current C Looking For Voltage Change,E, across the current source Current A Current B Current C Now I apply Kirchoffs laws for every loop. I go around in a counter clockwise manner and get the total drop in voltage for each. Loop A: -E+A+2(A-C)=0 Loop B: E+(B-C)+2(B)=0 Loop C: 12+(C-B)+2(C-A)+4C=0 Now i have 3 equations, but 4 unknowns, So i need another equation coming from the current provided from the current source to get a system of equations and solve it. But i know that the current source provides a current of 1amp for the loop, however this is where im not sure how to proceed, does it mean that both A and B = 1 or A=1 only? How do i know which current the source affects? I proceeded with the assumption that both A and B both equal one, but got an overdetermined system with no solution. On second though maybe, both currents are related by lets say, the source gives out current = 1amp, so loop 1 and 2 share this current so, currents A+B=1 sort of thing? Proceed by substituting A=1-B into the system of equations and get 3 unknowns 3 equations? Just need some checking on this fact and the rest of the problem is pretty straight forward. Thanks in Advance.