The choice of magnetic ring material

The magnetic ring is a lossy filter, which is mainly used to suppress the conducted interference on the cable.

When choosing a magnetic ring, two factors are mainly considered: the impedance characteristics of the magnetic ring and the interference characteristics of the filtered circuit. From the appearance point of view, the preferred choice is the magnetic ring with "as long as possible, as thick as possible, as small as possible in inner diameter, and as small as inductance". .

The biggest advantage of using a magnetic ring is that there is no electrical connection with the circuit to be filtered; the biggest disadvantage is that the magnetic ring is fragile, so it is recommended to use a magnetic ring with a plastic shell and fix it on the filtered power line or control cable. After the filtered power cable or control cable passes through the magnetic ring, it is repeatedly wound on the magnetic ring several times to increase the inductance of the cable and have a better interference suppression effect.

The electromagnetic waves radiated and leaked by electronic equipment not only seriously interfere with the normal operation of other electronic equipment, but also cause equipment dysfunction and transmission errors, but also threaten human health and safety, which is very harmful. Therefore, it is necessary to reduce the electromagnetic interference (EMI) of electronic equipment. Questions to consider.

Absorbing magnetic ring, also known as ferrite magnetic ring, or magnetic ring for short. It is a commonly used anti-interference component in electronic circuits and has a good suppression effect on high-frequency noise. Generally, ferrite material (Mn-Zn) is used. become.

According to the frequency characteristics of the interference signal, nickel-zinc ferrite or manganese-zinc ferrite can be selected. The high-frequency characteristics of the former are better than the latter. Zinc ferrite is hundreds---thousands. The higher the magnetic permeability of the magnetic ring 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, use manganese-zinc ferrite, 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.