Soft magnetic inductor is an electronic component , which mainly consists of a circular magnetic core. A horn inductor should be made for iron powder, ferrite, wires around it, or other materials. Longitudinal field coils are used in a wide range of applications, such as high frequency coils and transformers. Soft magnetic inductors can have higher Q factor and higher inductance construction than the same electromagnetic coils. This is largely because smaller turns are required to provide a closed core magnetic path. This flux is limited to the core at a high permeability, the energy consumed by confinement is reduced, and can be absorbed into nearby objects, so the ring coil provides some cores. The center of the threaded ring in the geometric magnetic flux direction, while the core parallel to the soft magnetic flux direction is the ring.Toroidal Inductors, Chokes & Coils

Both high frequency choke and low frequency choke are inductive coils. The inductance coil has the characteristic of restraining the change of current. The larger the inductance is, the more obvious this effect is. This effect hinders the current. The size of inductive reactance is related to the working frequency of inductance and the size of its own inductance.

Common mode inductor is a common mode interference suppression device with ferrite as the magnetic core. It consists of two coils with the same size and the same number of turns symmetrically wound on the same ferrite ring magnetic core to form a four terminal device. It is used to suppress the large inductance of common mode signal, but it has little effect on the small leakage inductance of differential mode signal. The principle is that when the common mode current flows, the magnetic flux in the magnetic ring overlaps with each other, so it has a considerable inductance and inhibits the common mode current. When the two coils flow through the differential mode current, the magnetic flux in the magnetic ring counteracts each other and has almost no inductance, so the differential mode current can pass through without attenuation. Therefore, the common mode inductance can effectively suppress the common mode interference signal in the balanced line, and has no effect on the differential mode signal normally transmitted by the line.Horizontal toroidal choke

Common mode inductors shall meet the following requirements during fabrication

1) The wires wound on the coil magnetic core shall be insulated from each other to ensure that there is no breakdown and short circuit between turns of the coil under the action of instantaneous overvoltage.

2) When the coil flows through an instantaneous large current, the magnetic core shall not be saturated.

3) The magnetic core in the coil shall be insulated from the coil to prevent breakdown between the two under the action of instantaneous overvoltage.

4) The coil shall be wound in a single layer as far as possible, which can reduce the parasitic capacitance of the coil and enhance the withstand capacity of the coil to instantaneous overvoltage.Toroidal choke coils

5) Generally, pay attention to the frequency band to be filtered at the same time. The larger the common mode impedance, the better. Therefore, we need to look at the device data when selecting the common mode inductance, mainly according to the impedance frequency curve. In addition, when selecting, pay attention to the influence of differential mode impedance on the signal, mainly pay attention to differential mode impedance, and pay special attention to the high-speed port.

The function of the low-frequency choke in the old class a audio power amplifier is to "connect DC and block AC". However, this ideal situation can not be satisfied, which can only be similar to "DC, AC". As long as the needs of the amplifier are met, a slight loss of a small part of the AC component is also allowed. The inductive reactance of the choke is larger here. When the frequency is certain (the audio range is 20khz-20hz), the inductance is required to be large. It is generally in the order of milliheng.

High frequency choke generally works in high-frequency current, and its function is mostly frequency selection, which requires that its inductance is not very large, generally in the order of micro Heng.

In fact, the terms "connect DC, resistance AC" and "connect low frequency, resistance high frequency" are for applications. But the purpose is to adjust the inductance of the inductor to meet our needs. Powder Toroidal Chokes.

1: Pay attention to the current value flowing through the choke, because the current capacity flowing through the choke is related to the cross-sectional area of the wire making the choke. When the wire diameter of the coil is too small and the current is too large, it will cause damage. Be sure to calculate the minimum current value and confirm the parameters with the rated current value of the choke.

2: When using the choke in the DC power supply, pay attention not only to the wire diameter of the coil of the choke, but also to the DC impedance value of the choke. If the current is large and the DC resistance is too large, the voltage drop of the choke will be too large and the output loss will be too large.

3: Pay attention to the suppression frequency characteristics of the choke when the choke is selected. The ability to suppress the frequency is proportional to the inductance of the choke. The larger the inductance, the center point of the suppression frequency will move to the low frequency direction. When the inductance is small, the suppression frequency will shift to the high frequency direction.