Why to set up the anti-interference magnetic ring?
_ ndfeb strong magnet manufacturers
Circular and there are many kinds of way, such as anti-interference magnetic ring, absorb the circular, shielding EMI/EMC magnetic ring, magnetic ring, ferrite beads, according to the market demand for EMI anti-interference magnetic ring, manufacturers and different performance and specifications of the anti-interference magnetic ring is developed, such as * * electronic production of the anti-interference magnetic ring is the buckle on the wire directly with plastic shell WRC/WF magnetic ring, suitable for flat FPC line using the FS type circular runway, and used in the power adapter plug-in braid magnetic bead inductance, and users are the most common use of RH/T on the wire end plastic circular magnetic ring, and so on.
These magnetic ring is can the function of filtering, filter out high frequency noise.
Why to set up the anti-interference magnetic ring?
Computer case motherboard, CPU, power supply, and within the IDE cable are working in the high frequency condition, in case there is a lot of space due to stray electromagnetic interference signal, and the intensity of the signal is outside the case several times to dozens times!
Absorption of the circular, also called ferrite beads, commonly used in removable separate magnetic ring, it is commonly used in electronic circuit anti-interference components, have very good inhibitory effect to high frequency noise, the use of ferrite materials (general
Copper under different frequencies have different impedance characteristics, generally in the low frequency impedance is very small, when the signal frequency impedance rise sharply increases the circular performance.
Through the normal useful signal is very good, and can restrain the high frequency interference signal through very good, and low cost.
Ferrite is a kind of ferrous cubic lattice structure of magnetic materials.
Ferrite materials for magnesium alloy iron or iron nickel alloy, its manufacturing process and mechanical properties similar to ceramic, color film.
Electromagnetic interference filter is often used in a class of magnetic core is ferrite materials, many manufacturers offer specialized for electromagnetic interference suppression of ferrite materials.
The characteristics of this material is a very big loss at high frequency, high permeability, he can is the inductance of the coil winding in the high frequency under the condition of high resistance between the minimum capacitance.
To suppress electromagnetic interference with ferrite, the most important performance parameter for magnetic permeability & mu;
Bs and saturation magnetic flux density.
Magnetic permeability & mu;
Can be expressed as the plural, real parts inductance, imaginary part on behalf of the loss, as the frequency increases.
As a result, its equivalent circuit series circuit of inductance L and R, L and R is a function of frequency.
When the wire through the ferrite core of inductance impedance is increased with the frequency and increase in form, but in different frequency when the mechanism is completely different.
Different ferrite inhibit element, the best inhibiting frequency range.
Generally the higher the permeability, inhibit the frequency of the lower.
In addition, the greater the volume of ferrite, inhibit the better the results.
In a certain volume, long and thin shape than stubby little inhibition effect is good, the smaller the diameter inhibition effect is better.
But with the help of dc or ac drift, and problems of ferrite saturation, inhibiting component cross section, the greater the more difficult saturated, affordable, the greater the flow deviation.
EMI absorption magnetic ring/magnetic beads differential mode interference suppression, through its current value is proportional to its volume, both disorders caused by saturation, reduces the component performance;
When the suppression of common-mode interference will power the two wires (
The positive and negative)
Through a circular and at the same time, the signal for the differential mode signal effectively, EMI absorption has no effect to its, magnetic ring/magnetic beads for the common mode signal will show a larger inductance.
The use of copper in have a better idea is to get through the copper wire around a few times repeatedly, to increase the inductance.
According to it for electromagnetic interference suppression principle, the rational use of its inhibitory effect.
Ferrite suppression components shall be installed near the interference sources.
For input/output circuit, should as far as possible close to the shielding casing of the inlet and outlet.
Of ferrite beads and magnetic beads absorption filter, in addition to should choose high magnetic permeability of a conductive material, but also pay attention to it.
They presented to the high frequency component in a circuit resistance is about ten to several hundred & Omega;
, so its role in the high impedance circuit is not obvious, on the contrary, in a low impedance circuit (
Such as power distribution, power supply or rf circuit)
The use of will be very effective.
Conclusion: because of the ferrite can decrease the high frequency at the same time make a almost unimpeded through the low frequency, therefore, has been widely used in the EMI control.
Used for EMI absorption can be made into various shapes of copper/magnetic beads, widely used in various occasions.
If on the PCB board, can add in DC/DC module, cable, power cord, etc.
It absorbs the high frequency interference signal on line, but won't produce new zero point in the system, not to damage the system stability.