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What is ferrite ring in electronic circuit

Ferrite ring, also known as a ferrite block, ferrite core, ferrite bead, is a ring-shaped part assembled from ferrite magnetic materials. With its unique structural characteristics and excellent magnetic properties, it has been widely used in electrical equipment such as motors and transformers. This article will introduce ferrite rings in detail in terms of types, structural features and applications.

Table of Contents

What is a ferrite ring

A ferrite ring or ferrite bead is a closed ring made of ferrite material. Ferrites are oxides composed of iron, oxygen and other metal elements and have excellent magnetic properties. A highly efficient magnetic circuit is created by forming a ring of ferrite material with a continuous magnetic flux path inside it. This annular structure allows the magnetic field to be concentrated inside, which reduces leakage loss, and enhances the permeability of the magnetic circuit.

Under the action of the ferrite ring, the normal and useful signals can pass through very well, and the passage of high-frequency interference signals can be well suppressed, and the cost is low, so it is widely used in display signal lines, USB cables, high-end keyboards and the mouse.

What is a ferrite ring and its types
What is a ferrite ring and its types

What are the different types of ferrite beads

The ferrite ring refers to a sintered magnetic metal oxide composed of various iron oxide mixtures. Manganese-zinc ferrite and nickel-zinc ferrite are typical magnetic core materials. Manganese-zinc ferrite has the characteristics of high magnetic permeability and high magnetic flux density. It is generally used in hundreds of KHZ-30MHZ, and has good impedance performance at low frequencies. Nickel-zinc ferrite has extremely high resistivity, generally used in high frequency, 1-1000MHZ.

1. Manganese-zinc ferrite
Manganese-zinc ferrite is one of the earliest invented ferrite magnets, and it is also the most widely used one. It is composed of iron, manganese, zinc and other elements, and has a high magnetic permeability, generally above 1000. Manganese-zinc ferrite is suitable for manufacturing magnetic products with high magnetic field, low cost, and insensitive to temperature changes, such as speakers, earphones, electromagnets, etc.

2. Nickel-zinc ferrite
Nickel-zinc ferrite is composed of iron, nickel, zinc and other elements. It has high electrical conductivity and corrosion resistance. It is suitable for manufacturing high-frequency, high-impedance, and high-sensitivity magnetic products, such as tape recorder heads and microphones.

What is the purpose of the ferrite ring

Ferrite ring plays an important role in electronics and power applications. Its main functions can be summarized as follows:

Magnetic field control and concentration
Ferrite ring can control and concentrate the magnetic field by forming a closed magnetic circuit. In power equipment such as AC power supplies and transformers, ferrite rings can be used to guide the flow of magnetic fields and reduce magnetic leakage losses. It can direct the magnetic field from one part to another to achieve the required magnetic circuit connection and power transfer.

Magnetic induction and energy conversion
Ferrite ring can perform various functions through magnetic induction and energy conversion. In an AC power supply, a ferrite ring converts electrical energy into magnetic energy and produces the desired electrical output at the load. In transformers and inductors, ferrite beads control the transfer of current and voltage and provide the required electromagnetic induction.

Suppresses Noise and Interference
Ferrite ring also has the ability to suppress noise and interference. In electronic equipment, ferrite ring can be used to absorb and shield high-frequency noise and interference to reduce interference to other circuits. This makes electronic equipment more stable and reliable, and improves its performance and anti-interference ability.

ferrite ring

What’s the characteristic of ferrite ring

1. Shape properties
The ferrite bead is generally a ring structure, composed of multiple pieces of ferrite material, the thickness of the material is 0.5-5mm, and the inner diameter and outer diameter are usually 50-300mm and 100-500mm respectively to meet the requirements of various applications.

2. Physical properties

The ferrite ring is a stable magnetic material at room temperature, and can stably exert its magnetic properties in the range of -55°C to 130°C. Especially in high temperature environments, its magnetic properties are superior to other magnetic materials.

3. Magnetic properties

Ferrite ring has very good magnetic properties, and its magnetic induction intensity can reach more than several thousand bits after electrification, and has the characteristics of high stability, high efficiency, low noise, etc., so it has been widely used in electrical equipment such as motors and transformers.

What’s the the application of ferrite ring

1. Application in motor

The engine magnet of the motor is generally a ring composed of ferrite rings, which can be filled with a certain amount of iron cores, and the iron cores will be attracted by the electromagnetic induction force in the ferrite rings, so that electrical energy can be converted into mechanical energy.

2. Application in Transformer

The variable-voltage magnetic core of the transformer is also composed of a ferrite ring. There is a winding on the ferrite ring. When the current passes through the winding, a magnetic induction force will be generated, so that the voltage can be converted into another constant voltage.

3.Application on PCB

The interference on the PCB mainly comes from the digital circuit, and its high-frequency switching current produces a strong interference between the power line and the ground line. The power line and signal line will transmit the high-frequency noise when the digital circuit switches in the form of conduction or radiation. A commonly used interference suppression method is to add a decoupling capacitor between the power supply and the ground so that the high-frequency noise is short-circuited. However, using decoupling capacitors alone can sometimes cause high-frequency resonance and cause new interference. Adding ferrite beads at the entrance of PCB circuit board traces to suppress interference, which effectively attenuate high-frequency noise.

4. Application in other devices

In addition to motors and transformers, ferrite rings can also be used in amplifiers, electronic scales, electronic game consoles and other equipment, all of which need to exert the unique magnetic characteristics of ferrite rings.

What’s the the application of ferrite ring
What’s the the application of ferrite ring?

What’s the importance of the ferrite ring in EMC

Filtering effect: In the electromagnetic environment, the equipment may be interfered by noise of various frequencies, affecting its normal operation. As a filter element, the ferrite core can filter out the noise of a specific frequency according to the needs, so as to ensure the stable operation of the equipment. For example, in the power filter, the ferrite core can filter out the noise in the power line to ensure the stable power supply of the equipment.

Suppression of Electromagnetic Interference (EMI): Electromagnetic Interference (EMI) refers to the electromagnetic radiation generated by equipment to the surrounding environment during operation. This electromagnetic radiation may cause interference to other equipment, and even affect its normal operation. The ferrite core can effectively suppress this electromagnetic interference. When the interference signal tries to pass through the ferrite bead, due to the inductive reactance of the ring, the interference signal will be weakened or reflected, thereby protecting the circuit from external interference.

Resonance effect: The ferrite core can resonate with the circuit at a specific frequency, thereby improving the filtering effect of the circuit. By adjusting the inductance value and frequency of the ferrite bead, the best filtering effect of the circuit can be achieved to ensure the normal operation of the device.

To sum up, the ferrite ring is a magnetic material with unique structural characteristics and excellent performance. It can be applied to motors, transformers and other equipment. It has the characteristics of high stability, high efficiency and low noise. An indispensable key component in today’s electrical equipment.


A ferrite ring or ferrite bead is a closed ring made of ferrite material. Ferrites are oxides composed of iron, oxygen and other metal elements and have excellent magnetic properties.

Manganese-zinc ferrite and nickel-zinc ferrite are typical magnetic core materials.

It can be applied to motors, transformers, PCB and other equipment.

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