By my reckoning, the energy in L1 is 720 nJ at the peak of the ramp, and the energy in L1+L2 just after the FET opens is 490 nJ. But this isn't it. Your graph looks wrong. How to simulate a tapped inductor in EasyEDA. The inductors or coils are passive components that have a certain number of turns of wire that introduce magnetic inductance to an electrical circuit to produce a magnetic flux or to mechanically react to magnetic flux variations.