We introduce a method to use z parameters to model the interface between an electric circuit and a magnetic component. With this model, the electrical equivalent circuit of any complex integrated magnetic component can be developed easily. We describe the simulation and design of integrated magnetics using a z-parameter two-port network model. We use a single-switch regulator with power-factor-correction and a single integrated magnetic component as an example to demonstrate the practical applications of integrated magnetics in modern power converters. For the same example, we analyze the problem of uneven magnetic flux density in an integrated magnetic component and propose a possible solution to the problem.