This paper presents an extended Cauer-equivalent circuit model of inductors that can represent not only eddy-current effects but also capacitive properties. As this model considers the skin and proximity effects of the winding as well as the parasitic capacitance, it is accurate from DC to more than 500 MHz, even with multiple resonances. The resonant characteristics are expressed by RLC series circuits in parallel with a Cauer circuit representing the inductive part. The extended Cauer circuit can be embedded in circuit simulators to perform time-domain as well as electromagnetic-interference simulations.