In order to make the calculations required of a Real Transformer we simply use an ideal transformer with “add-ons” that when added to the circuit produce that “equivalent” results. This is know as the “Equivalent Circuit” of a transformer. Modeling the copper losses or resistive losses in the primary and secondary windings of the core, are represented in the equivalent circuit by R1 and R2. Modeling the primary & secondary leakage flux, are represented in the equivalent circuit by L1 and L2, The core excitation is modeled by LM. and the core eddy current and hysteresis losses is modeled by RC.