Hi, I have a question relating to the image below. http://img830.imageshack.us/img830/2173/elec.png/ [Broken] From step 2 to 3, I get how 120V becomes 20mA but how is the 6k ohms affected? Why is it reduced to 3k ohms? And from step 1 to step 2, why isn't it like below? Case 2b instead of 2a? http://img835.imageshack.us/img835/9250/elech.png [Broken] I arrived at the answer using a different technique but I would like to understand this one too. Thank you very much.