1. The problem statement, all variables and given/known data Three equal resisters are connected to a battery. If the emf of the battery is 15V, what is its terminal voltage when the switch is closed if the internal resistance is 0.5 ohms and R= 5.5ohms? What is the terminal voltage when the switch is open. 2. Relevant equations V=IR; V terminal = E- Ir jpg.gif Untitled.jpg (7.6 KB) 3. The attempt at a solution See Picture So I'm not sure if you need to apply Kirchhoffs rules here or not. It seems simple enough that you might not have to? I first tried treating everything vertically as parallel and then adding it to the horizontal R as though it were in series Then I tried adding everything in the first box as though it were in series and adding that to the outside R as though they were in parallel with each other. In both cases I then used the equivilant value for R and used it with the emf to find the terminal voltage. Both cases gave me voltages in the high 13's, but the answer is 14.1V can anyone start me off the right way?