1. The problem statement, all variables and given/known data Assuming that D1 and D2 are ideals, determine ID1 and ID2 according to the table below. 2. Relevant equations Circuit Analyzing methods (KVL, etc...) 3. The attempt at a solution I've confirmed my solutions for the first three cases with final answers of the book I use and also with Multisim. But for the fourth, while replacing the diodes with "on-switches", I used superposition to calculate the currents. I've ended up with ID1=ID1'+ID1''=12+9=21 mA, and ID2=-9 mA. My answer is correct for ID2, but that not the case for ID1 (The answer should be 12 mA). Looks like the effect of the 9V source on ID1 was ignored. Why is that?