This section provides an overview for ferrite cores as well as their applications and principles. Also, please take a look at the list of 10 ferrite core manufacturers and their company rankings.
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A ferrite core is a ceramic magnetic material called ferrite, which is mainly composed of iron, and is processed according to the application.
The use of ferrite as a magnetic core can block high-frequency currents, and is therefore effective as a noise suppressor. Ferrites are classified into different systems according to their composition, but Ni-Zn ferrites are mainly used for noise reduction.
The reasons for this are that the Ni-Zn type does not require insulation processing and has excellent high-frequency characteristics. Noise can be eliminated by passing a cable through a ring-shaped ferrite core.
Ferrite cores are used for noise reduction in electronic equipment. The noise-reducing effect of ferrite cores is not limited to noise entering the cable from the outside, but can also eliminate noise generated by the cable itself.
Ferrite cores are simple, inexpensive noise suppression components and are characterized by their easy handling. Therefore, noise suppression can be implemented without the need for design changes to the board or circuitry. Therefore, they can be used as an experimental method before finalizing the final specifications or as an emergency noise suppression measure.
There are two main principles by which ferrite cores can eliminate noise: First, they act as a filter to cut high-frequency frequencies and eliminate noise caused by high-frequency currents.
When electricity flows through the hole in the ferrite core, the cable becomes an inductor, and the impedance of the cable changes according to the magnetization of the ferrite core. At this time, the impedance becomes higher in the high-frequency band, enabling attenuation of high-frequency currents that are noise components.
Second, hysteresis loss allows noise current to be dissipated as thermal energy. When an inductor is configured by a ferrite core and an alternating current flows through it, the generated magnetic field fluctuates in direction and magnitude with time in a certain period.
The magnetization of the ferrite core making one cycle is called a hysteresis loop, and the loss of energy that occurs during this process is called hysteresis loss.
When selecting a ferrite core, there are some things to keep in mind.
A soft magnetic material called soft ferrite is used for ferrite cores. Oxides of transition metals such as nickel, iron, zinc, and copper are the main raw materials. Since the permeability of soft ferrite can be changed by its composition, the impedance can be tuned by the ratio of the main raw materials.
Impedance has two components, namely reactance and resistance. The material composition of a ferrite core for noise rejection contains a large amount of resistance component. Therefore, noise rejection is more effective in dissipating the energy of noise current as heat due to hysteresis loss than in filtering to cut high frequencies.
The noise rejection performance of a ferrite core is evaluated by its impedance. Impedance is determined by material properties, shape factor, and number of turns.
The material properties are determined by the composition of the soft ferrite. The shape factor is the cross-sectional area of the ferrite core divided by the average magnetic path length. Therefore, a ferrite core with a large cross-sectional area and a small inner diameter performs better. For better noise rejection, wrapping the cable around the ferrite core multiple times is also effective.
However, when a conductor is wound more than once, the beginning and end of the winding are close to each other, creating stray capacitance between them. Since this stray capacitance reduces the effectiveness of countermeasures against high-frequency components, it is necessary to wind the cable while keeping an eye on the frequency band for which noise reduction is desired.
*Including some distributors, etc.
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KEMET has a portfolio of over 1,600 patents serving the automotive, aerospace, industrial, telecommunications, computing, consumer, and medical devices. KEMETs devices provide filtering, sensing, energy storage, power conversion, and haptic actuator technology. Among these devices are capacitors, electromagnetic compatibility (EMC) components, resistors, circuit protection devices, inductors, sensors, Piezoelectric devices, release, transformers, and engineering kits.
Hybrid Electronics is a global distribution specialist of electronic components, with access to over 50 million unique components. Among the markets HE serves are the aerospace, automotive, communications, defense, industrial, medical, national security, and test & measurement industries. In addition to components, HE also provides quality and compliance testing, counterfeit detection, upscreening, and other forms of quality control. Examples of component subtypes that HE offers include ICs, batteries, capacitors, semiconductor products, sensors, circuit protection, interconnectors, filters, optoelectronics, relays, switches, power supplies, and cables and cable assemblies.
Würth Elektronik was founded in 1971 and is headquartered in Niedernhall in Baden-Württemburg, Germany. The company is a manufacturer of circuit board-related components, electronic & electromagnetic components, and intelligent systems including power distribution and function control. The company’s electronic and electromagnetic components include power modules, passive components, wireless connectivity devices, and sensors. The company’s printed circuit boards include basic, flexible and semi-flexible, printed polymer, and rigid boards and thermal management products. The company’s intelligent power and control systems products include displays, central electrical controllers, and electronic controllers.
Ranking as of June 2023 Globally
Derivation MethodRank | Company | Click Share |
---|---|---|
1 | KITAGAWA INDUSTRIES CO., LTD. | 20% |
2 | TDK Corporation. | 10% |
3 | MAGNETICS | 10% |
4 | Fair-Rite Products Corp. | 10% |
5 | Ferroxcube. | 10% |
6 | Magnetic Metals Corp. | 10% |
7 | W?rth Elektronik | 10% |
8 | King Core | 10% |
9 | KEMET | 10% |
Derivation Method
The ranking is calculated based on the click share within the ferrite core page as of June 2023. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
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