1. The problem statement, all variables and given/known data Calculate the equivalent impedance about terminals A and B. [PLAIN]http://img218.imageshack.us/img218/9335/circuits827.png [Broken] Z1 = -j2 ohms Z2 = 1 ohm Z3 = j2 ohms Z4 = 2 ohms 2. Relevant equations Adding parallel: Zeq = z1*z2/z1+z2 Adding in series Zeq = z1+z2 3. The attempt at a solution I honestly have been staring at this problem for hours and cannot figure it out. I'm beginning to wonder if you have to perform a Y to Delta transformation about Z1, Z3, and Z4. Without doing that I cannot see how to simplify this problem. Is there another way? Or, is that the only way to solve it by doing a Y to Delta transformation about Z1, Z3, and Z4. Help / advice much appreciated in advance.