Basic introduction of magnetic loop inductance

Hello, everyone. Today I'll share with you the basic introduction of magnetic ring inductance. I hope you have a certain understanding after reading it.


What is magnetic loop inductance

In the high-frequency section of the magnetic ring inductance, the impedance is mainly composed of the resistance component. With the increase of the frequency, the permeability of the magnetic core decreases, resulting in the decrease of the inductance and the inductive reactance component of the inductance. However, at this time, the loss of the magnetic core increases and the resistance component increases, resulting in the increase of the total impedance. When the high-frequency signal passes through the ferrite, the electromagnetic interference of the inductance is absorbed and converted into the form of heat energy for consumption. In the low frequency band, the impedance is mainly composed of the inductive reactance of the inductor. At low frequency, R is very small, and the permeability of the magnetic core is high. Therefore, the inductance is large, the inductance L plays a main role, and the electromagnetic interference is restrained by reflection. At this time, the loss of the magnetic core is small. The whole device is an inductor with low loss and high quality factor Q characteristics, which is easy to cause resonance, Therefore, in the low frequency band, the interference may be enhanced after using ferrite magnetic beads.

 

 Working principle of magnetic loop inductance

 Because the use of ferrite magnetic beads in the circuit can increase the high-frequency loss without introducing DC loss, and the volume is small, it is easy to be installed on the lead or wire in the section, and the suppression effect of noise signals above 1MHz is very obvious. Therefore, it can be used as decoupling, filtering and parasitic oscillation suppression of high-frequency circuits.

 

For low impedance power supply circuit, resonant circuit, class C power amplifier and thyristor switching circuit, it is very effective to use ferrite magnetic beads for filtering. Ferrite magnetic beads made of magnetic ring inductance can generally be divided into resistive and inductive, which can be selected according to needs. The impedance of a single magnetic bead is generally ten to hundreds of ohms. If one attenuation is not enough, multiple magnetic beads can be used in series, but the effect will not increase significantly when there are more than three.

 

Function of magnetic loop inductance

Inductance is mainly filtering, oscillation, delay and notch. It is vividly said that "DC is connected and AC is blocked". Magnetic beads are mainly used to suppress electrical radiation interference, high-frequency noise and peak interference and absorb UHF signals. They are often used in PCB, DC / DC module, high-frequency switch, switching audio amplifier, data line, power line, signal line, etc. So what's the difference between inductance and magnetic bead?

 

1. The frequency characteristics of the magnetic bead of the magnetic ring inductance are different from those of the inductance. In the low frequency band, the inductance of the magnetic bead becomes larger and the resistance of the winding inductance becomes smaller. The inductance of the magnetic bead works and can be regarded as an inductor with low loss and high Q value; In the high-frequency band, the magnetic bead inductance becomes smaller and the resistance becomes larger, resulting in the increase of the total impedance, which can be regarded as a high-frequency device.

 

2. The size of the magnetic bead of the magnetic ring inductance completely depends on the frequency and strength of the interference wave to be absorbed. Main parameters based on: impedance (in Ω), DC resistance (in M Ω) and rated current (in MA) when the frequency is 100MHz.

 

Well, that's all for our introduction. If you have any questions, please leave a message. If you want to know more, please pay attention to us. See you next time.