1. The problem statement, all variables and given/known data This is the circuit: http://img129.imageshack.us/img129/3566/pfcog8.jpg Assume voltage is in rms and f is 50Hz. I have to do three things. First, calculate and compare true power vs apparent power in the load. Second, find the value of a capacitor placed in parallel that would bring the LOAD to unity power factor. Finally, calculate the real power in the circuit (both transmission and load impedances) with and without this capacitor, and compare them. 2. Relevant equations 3. The attempt at a solution I didn't have a problem with the first part. The load impedance is (8 + j3) ohms. Power worked out to be 6212.33 + j2367.12. So true power was 6312.33 W and apparent was 6741.57 I'm having trouble with the second part. I've been told that I need to use: Zcorrected load = Zc || (Zr + ZL) which becomes Zcorrected load = [Zc * (Zr + ZL)] / [Zc + (Zr + ZL)] But I'm not sure how to manipulate this to give me the value of Zc. And I can't even start the third part until I've worked this out. Please help.