high frequency noise of signal lines, power cords and peak interference, have the ability to absorb electrostatic pulse. Magnetic beads are used to absorb the uhf signals, like some RF circuit, PLL, oscillating circuit, including uhf memory circuit (DDRSDRAM, RAMBUS, etc.) need to be in power input part and magnetic beads, and inductance is a kind of energy storage component, used in LC oscillation circuit, the low frequency of filter circuit, etc., and its application rarely more than 50 MHZ frequency range. Magnetic beads has high resistivity and magnetic conductivity, equivalent resistance and inductance in series, but the resistance and inductance value is changing with frequency