1. The problem statement, all variables and given/known data 2. Relevant equations power loss = I2R power loss = V2/R 3. The attempt at a solution voltage across diode is 0.7V, current is 100A. resistance = 0.01 ohm. Power loss is I2R - 100 * 100 * 0.01 = 100 W Power loss across IGBT = V2/R. V across IGBT = V across Diode = 0.7. R for IGBT = 0.02 ohm So loss is 0.7 * 0.7 / 0.02 = 24.5W Total loss is 100 + 24.5 is 124.5 W But they've done something like: No current through IGBT Conduction loss = VtIav + Irms2Ron = 0.7 * 100 + 1002 * 0.01 = 170W. Why did they do V * T + I2R? Shouldnt they do either one? and i'm not sure which one.