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The Role And Principle Of Magnetic Ring Inductance, To Understand It!

2022-06-02

Inductance is the ratio of the magnetic flux in a wire to the current producing the alternating flux around the inside of the wire when an alternating current is flowing through it.


When the dc current passes through the inductance, only fixed magnetic field lines are present around it, which does not change with time. But when an alternating current passes through a coil, it is surrounded by magnetic field lines that change over time. According to Faraday's law of electromagnetic induction, magnetic generation, the changing magnetic field lines create an induced potential at both ends of the coil, which acts as a "new power source". This induced potential generates an induced current when a closed loop is formed. Lenz's law knows that the total amount of magnetic lines of force produced by an induced current should try to prevent the change of magnetic lines of force. The change of magnetic force line comes from the change of external alternating power supply, so from the objective effect, the inductance coil has the characteristic of preventing the current change in ac circuit. The inductance coil has similar characteristics to the inertia in mechanics, which is called "self-induction" in electricity. Usually, sparks will occur at the moment when the knife switch is opened or switched on. This self-induction phenomenon is caused by high induction potential.


In short, when the inductance coil is connected to the AC power supply, the magnetic field lines inside the coil will change with the alternating current, causing the coil to produce electromagnetic induction. This electromotive force due to the change in the current of the coil itself is called "self-induced electromotive force".


It can be seen that the inductance is only a parameter related to the coil number, size and shape and medium, it is the measurement of the inductance coil inertia and has nothing to do with the applied current. The digital device transmission line has a cylindrical object. What is this? It is magnetic ring, anti-interference magnetic ring, or absorption magnetic ring, ferrite magnetic ring.


Why should anti-jamming magnetic rings be set? The motherboard, CPU, power supply, and IDE data line in the computer case all work at a very high frequency, so there is a lot of space stray electromagnetic interference signal in the case, and the signal intensity is several times to tens of times of the case outside! USB cables without magnetic rings are not shielded in this space, so these USB cables make a good antenna, picking up all kinds of messy high-frequency signals in the surrounding environment, and these signals can be superimposed on the original transmission signal, and even change the original transmission of useful signals, prone to problems.


Absorption magnetic ring, also known as ferrite magnetic ring, often used for removable separation magnetic ring, is commonly used in electronic circuit anti-interference components, for high frequency noise has a good suppression, generally made of ferrite material (Mn-Zn). The magnetic ring has different impedance characteristics at different frequencies. Generally, the impedance is very small at low frequency, and the impedance of the magnetic ring increases sharply when the signal frequency increases. So that the normal useful signal is very good through, and can well suppress the high-frequency interference signal through, and the cost is low.


Ferrite is a kind of high permeability magnetic material permeated with one or more metals such as magnesium, zinc and nickel at 2000℃.


In low frequency band, ferrite anti-jamming core presents very low inductive impedance value, which does not affect the transmission of useful signals on data lines or signal lines. However, in the high-frequency band, starting from about 10MHz, the impedance increases, and the inductive component remains small, while the resistive component increases rapidly. When the high frequency energy passes through the magnetic material, the resistive component will dissipate the energy into heat energy. In this way, a low-pass filter is formed, so that the high-frequency noise signal has a large attenuation, and the impedance of the low-frequency useful signal can be ignored, does not affect the normal operation of the circuit.


Different ferrite suppression elements have different optimal suppression frequency range. In general, the higher the permeability, the lower the frequency of inhibition. In addition, the larger the volume of ferrite, the better the inhibition effect. When the volume is constant, the long and thin shape is better than the short and thick shape, and the smaller the inner diameter is, the better the inhibition effect is. However, in the case of DC or AC bias, there is also the problem of ferrite saturation. The larger the cross section of the restraining element is, the less saturated it is, and the larger the allowable bias is.


In order to improve the transmission rate and stability, and to reduce the interference of transmission line to other equipment, such as sound card, electrostatic shielding layer is designed. The shield is made of a thin metal foil or a network of strands of fine copper wire, using the principle of surface effects of electrostatic fields. That is, the outer surface of the data transmission line bread on a layer of metal film, and the shielding layer grounding with the chassis, you can be very good data line and space interference signal isolation! Magnetic rings have different impedance characteristics at different frequencies. At low frequency, the impedance is very small, and when the signal frequency increases, the impedance of the magnetic ring increases sharply.


As you all know, the higher the signal frequency, the more radiation, and signal lines are not shielding layer, these signal lines is a very good antenna, receiving all kinds of clutter in the surrounding environment of high frequency signals, and the signal is superimposed on the signal transmission, even change the useful signal transmission, seriously interfere with the normal work of the electronic equipment, Reducing electromagnetic interference (EM) from electronic devices has been considered. Under the action of magnetic ring, even if the normal useful signal passes through smoothly, the high-frequency interference signal can be suppressed very well, and the cost is low.



                                Whc2026-5026 Electrical characteristics table


The five rings of the goods PART NO

Inductance Value(uH)

Rated Current(A) MAX

Direct Current Resistance(OHM)MAX

A Size (MM)MAX

D Size (MM)MAX

Unit Weight(G/PCS)

WHC-5R0M-2026

5.0

0.5

0.007

7.5

4.5

0.4

WHC-9R0M-2026

9.0

0.3

0.011

8.0

4.5

0.2

WHC-150M-2026

15

0.5

0.07

7.5

4.5

0.4

WHC-200M-2026

20

0.2

0.198

7.5

4.0

0.2

WHC-270M-2026

27

0.3

0.031

8.0

4.5

0.2

WHC-100M-3026

10

2.0

0.017

12.0

7.0

1.6

WHC-120M-3026

12

1.0

0.04

10.5

6.0

1.2

WHC-320M-3026

32

1.0

0.065

12.0

7.0

1.4

WHC-370M-3026

37

0.5

0.134

10.0

5.5

1.0

WHC-141M-3026

140

0.5

0.265

10.0

6.0

1.2

WHC-8R2M-3726

8.2

2.0

0.017

14.5

7.0

2.0

WHC-220M-3726

22

2.0

0.03

14.5

7.5

2.4

WHC-240M-3726

24

1.0

0.055

13.5

6.0

1.6

WHC-560M-3726

56

0.5

0.181

12.5

5.5

1.4

WHC-680M-3726

68

1.0

0.095

13.5

6.5

2.0

WHC-241M-3726

240

0.5

0.36

13.0

6.5

1.6

WHC-150M-4426

15

2.0

0.023

15.5

7.5

2.8

WHC-430M-4426

43

1.0

0.074

14.5

7.0

2.6

WHC-680M-4426

68

2.0

0.056

15.5

9.0

3.8

WHC-111M-4426

110

0.5

0.25

14.0

6.5

2.4

WHC-141M-4426

140

1.0

0.14

15.0

7.5

3.2

WHC-361M-4426

360

0.5

0.46

14.5

7.5

2.8

WHC-200M-5026

20

3.0

0.021

17.5

9.0

4.4

WHC-300M-5026

30

2.0

0.035

17.0

8.5

4.0

WHC-600M-5026

60

3.0

0.038

18.0

10.0

5.8

WHC-680M-5026

68

1.0

0.101

16.0

7.5

3.6

WHC-101M-5026

100

2.0

0.081

17.0

9.5

5.2

WHC-221M-5026

220

1.0

0.19

16.5

8.0

4.4

K:+10% ;M:+20%   The inductance and current can be customized according to customer needs