Real Life Inductor : When Does An Inductor Stop Behaving Like One

1. When current is too high – because of magnetic saturation
2. When signal of interest is of too high frequency – higher or near inductor self resonant frequency. There are parasitic capacitance across inductor winding  so in a way, we have parallel LC circuit, at high enough frequency, the impedance of C will gets low enough to shunt out the impedance of inductor.