Electromagnetic compatibility depicted in digital circuits process, we often use the beads, bead filters principles and how to use it then?
　　Magnesium alloy ferritic iron or iron-nickel alloy with high permeability data, it can be considered as the minimum capacitance frequency high inductance coil impedance between stops. Ferrite materials are usually in high frequency applications, due to the low frequency, lost their primary method of inductance characteristics of small row. High frequency, which is the primary reactance and frequency characteristics. As a high-frequency RF circuit for practical application of ferrite attenuation data. In fact, the ferrite is equal to the resistance and inductance of the circuit, the shunt resistor is short, high frequency inductive impedance low-inductance is not high enough, all the current through the resistor. Ferrite equipment cost, high-frequency energy in the above resolution by the function.
　　Ferrite beads inductor is high compared to a normal high frequency filtering characteristics, the resistive layer ferrite indicated at high frequency, the equivalent inductance is very low quality, they can get a high impedance over a wide frequency range, That is a high-frequency power supply filtering. In the low frequency impedance, inductance reactor, R is very small, at low frequencies, during which high permeability, inductors center, plays an important effect of large, taking into account the electromagnetic interference of inhibition, but this time low iron loss of 　　magnetic field, the whole equipment and low-loss high-Q inductors actions may have low frequency resonance, sometimes disrupt the progress of the use of ferrite bead inductors. In the high frequency impedance of the resistive components, when the frequency is added, the heart rate of permeability, composition cut inductance inductance, but if it is the central part of the losses add the total impedance against Add add, high-frequency signal is troubled by absorbing electromagnetic ferrite, and converted into heat.
　　Ferrite restrain element widely used in printing circuit boards, power lines and data lines. Plus ferrite restrain element, such as a network adapter plate, you can filter out high frequency noise. Ferrite beads or bead control signal lines, power lines, and the introduction of dedicated high-frequency distortion, it also has the ability to absorb electrostatic discharge pulses.