Consider a simple circuit of Real inductor exited by sinusoidal Source. What is getting me into trouble is this. 1. What is the current through the inductor? Isn't it the same as that of resister,which is [tex]\phi[/tex] phase lagging with the applied voltage. (Current is same in a series branch) 2. Considering that this inductor is the part of a transformers primary winding, the magnetic Flux Will also be [tex]\phi[/tex] phase lagging with applied field since Flux is directly proportional to the current (Assuming linear relation between B and H) But my teachers and my text-book says that in transformer, the magnetic Flux produced is perfectly 900 out of phase with the applied Voltage. My teacher said that only the 900 component of the current is used in producing the flux and the in-phase component will be simply lost in the resistive heating. So I want you to explain to me what this the phase of flux produced?