Views: 3 Author: Site Editor Publish Time: 2021-04-26 Origin: Site
The magnetic ferrite ringscore on the connecting line&cable are basically divided into two types, one is a nickel-zinc(NiZn emi/emc core) ferrite magnetic ring, and the other is a manganese-zinc ferrite magnetic ring, they play a different role. Manganese-zinc ferrite core has the characteristics of high magnetic permeability and high magnetic flux density, and has low loss characteristics at frequencies below 1MHz. Nickel-zinc ferrite has the characteristics of extremely high resistivity, low permeability of less than a few hundred, and low loss at frequencies higher than 1MHz-1000MHZ. The permeability of manganese-zinc ferrite is in the thousands --- tens of thousands, while the permeability of nickel-zinc ferrite is in the hundreds ---thousands. The higher the permeability of ferrite, the greater the impedance at low frequencies and the smaller the impedance at high frequencies. Therefore, when suppressing high-frequency interference, nickel-zinc ferrite should be used; otherwise, manganese-zinc ferrite should be used. Or put manganese-zinc and nickel-zinc ferrite on the same cable at the same time, so that the interference frequency band that can be suppressed is wider. The greater the difference between the inner and outer diameters of the magnetic ring and the greater the longitudinal height, the greater the impedance, but the inner diameter of the magnetic ring must be tightly wrapped around the cable to avoid magnetic leakage. The installation position of the magnetic ring should be as close to the interference source as possible, that is, it should be close to the entrance and exit of the cable
Principles of using magnetic cores
1 The longer the magnetic ring ferrite, the better the magnetic ferrite core
2 The tighter the aperture and the cable passing through are combined, the better. 3 When the low frequency end is disturbed, it is recommended to wind the cable with 2 to 3 turns. When the high-frequency end is disturbed, it cannot be wound (due to the existence of distributed capacitance). Choose a longer magnetic ring.
Installation position of the magnetic ring ferrites
The installation position of the magnetic ring should be as close as possible to the source of interference, that is, close to the entrance and exit of the cable.