The impedance modeling of passive device is mandatory for EMI prediction of power converter on printed board circuit (PCB) level. The black-box node-to-node impedance function (NIF) model, which extracts the connecting impedance matrix from measurement, can be used as the most general representation. However, the most recent development of this model is still based on the assumption of ideal shorting path used in measurement, which is not true since its small inductance results in high impedance in EMI frequency. It interacts with small inductive and high capacitive impedance of popular passive devices used in the power converter, i.e. common choke, LC filter, power supply, resulting in computational errors of the connecting impedance matrix. In this paper, the errors in the model created by shorting path impedance is analyzed and eliminated by employing the Newton — Raphson (NR) iterative method. This work helps to improve the precision of the model, herein called general impedance representation (GIR); and hence, enables it to be applied for all kinds of passive devices without knowledge of the device's specific model. The experimental results are presented to confirm the effectiveness of the proposed GIR.