FerriteBead is a rapidly developing anti-interference component that is cheap, easy to use, and has a significant effect on filtering high-frequency noise.

The main raw material of magnetic beads is ferrite. Ferrite is a kind of Ferrimagnetism material with cubic lattice structure. The ferrite material is iron magnesium alloy or iron nickel alloy, and its manufacturing process and mechanical properties are similar to ceramics, with a gray black color. A type of magnetic core commonly used in electromagnetic interference filters is ferrite material, and many manufacturers provide ferrite materials specifically for electromagnetic interference suppression. The characteristic of this material is that it has very high high-frequency losses and high permeability, which can minimize the capacitance generated between the coil windings of the inductor under high-frequency and high resistance conditions. The most important performance parameter for ferrite used for suppressing electromagnetic interference is magnetic permeability μ And saturation magnetic flux density Bs. Magnetic permeability μ It can be expressed as a complex number, with the real part forming the inductance and the imaginary part representing the loss, which increases with frequency. Therefore, its equivalent circuit is a series circuit composed of inductance L and resistance R, both of which are functions of frequency. When the conductor passes through this Ferrite core, the inductance impedance formed increases with the increase of frequency in form, but its mechanism is completely different at different frequencies.

In the low frequency range, impedance is composed of the inductance of the inductor. At low frequencies, R is very small, and the magnetic permeability of the magnetic core is high. Therefore, the inductance is large, and L plays the main role. Electromagnetic interference is suppressed by reflection, and at this time, the loss of the magnetic core is small. The entire device is a low loss, high Q characteristic inductor, which is prone to resonance. Therefore, in the low frequency range, sometimes there may be increased interference after using ferrite magnetic beads.