The impedance of a chip bead is composed of a frequency dependent resistance and a parallel inductance. From equation (1), the resistance of chip bead depends on the relative permeability (µs) of the ferrite materials with frequency characteristics as determined by the permeability value. The chip bead reduces the high frequency noise by using the resistance (loss) component of the impedance. The frequency where the resistive value becomes higher than the inductive value is known as the cross-point. The bead usage and value should be determined with this cross-point in mind.