Frequency characteristics of ferrite core inductors

An equivalent model of inductors at high frequencies is developed taking into account equivalent series resistance (ESR) and the parallel equivalent resonant capacitance. An expression representing the equivalent inductance (L_s) of an inductor is derived. It is shown that an inductor behaves like a capacitor beyond its resonant frequency. Various parameters such as inductance, capacitance, quality factor (Q), ESR, impedance (Z), and phase angle (φ) are measured over a wide range of frequency for the pot core and toroidal core inductors. Then graphs of these parameters are plotted and interpreted