It refers to a core of magnetic metal oxide sintered iron from various mixtures thereof, e.g., Mn - Zn ferrite, and Ni - Zn ferrite is a typical core body information. Manganese - zinc ferrite having a high magnetic permeability and high magnetic flux density characteristics, and at frequencies below 1MHz, with a lower loss characteristics. Ni - Zn ferrite has a very high impedance, low magnetic permeability of less than hundreds of other features, and also the occurrence frequency higher than 1MHz low wear and tear. Ferrite cores used in various electronic devices coils and transformers.
　　Absorption ring, known as a ferrite bead, called ring, it is the electronic circuit element commonly used in anti-interference, on the high-frequency noise has an excellent inhibition effect, usually use ferrite materials (Mn-Zn) system to make.
　　Ring at different frequencies have different impedance characteristics, usually small impedance at low frequencies, when the signal frequency is increased ring reflects a sharp rise in impedance.
　　We all know that the higher the frequency of the signal, the more simple radiated out (to buy high-quality computer chassis is to reduce the electromagnetic leak), but usually the signal lines are no shield, then these lines it would be a good signal antenna admission surroundings various messy high-frequency signal, which signal is superimposed on the original transmission signal, and even change the original transmission of the useful signal. So in effect ring, so that the normal useful signal through an excellent, excellent restrain high frequency can disturb the signal through, and costs low.