Ferrite Cores

Ferrite Cores: What Are They?

Ferrite cores are exceptionally common parts of electronic components. They are most notably used in transformers, where the windings around the core give the transformer the ability to alter the current or voltage that is fed through the primary winding. There are many other electrical components that utilize ferrite cores, however, as well and there are several different types of ferrite cores in common usage.

The various materials used for ferrite cores are typically chosen based on the application. Not only do these materials have the capability of functioning as the core in a transformer, they also have tremendous capabilities in terms of reducing electrical interference and are heavily used in radio equipment. Ferrite cores are among the most versatile and important pieces of basic electronics equipment of all. Many different types of equipment cannot be manufactured without the materials that go into these seemingly simple components and, without those types of equipment, many modern electronic devices would simply fail to function as intended.


History of Ferrite Cores

As any student of electronics history knows, a great many of the advances that still drive today's technology were first made in the 1800s. By the early 1800s, the property of induction had already been discovered and, not too long thereafter, experimenters were working on transformers and using them in lighting systems.

Ferrite is a term that is interchangeable with pure iron in material science, but the meaning is somewhat different in magnetics. In magnetics, ferrites are compounds that include iron oxide and ceramic materials. These are the types of cores that are found in modern transformers, though other materials were experimented with initially.

Today, ferrite cores are used in electronics in a variety of different components that require winding. Ferrite is characterized by having high magnetic permeability. Ferrite also has low electrical connectivity and the combination of these two characteristics make it ideal for use in transformers and many other applications. Ferrite cores are also found used in loop stick antennas and in switched mode power supplies.

Most people have likely seen ferrite cores at use in computer equipment. At the end of many computer cables, a plastic cylinder or other device contains a ferrite bead that reduces interference. Open up the inside of a computer case and you'll find many different types of cables, some of them protected by ferrite cores that serve the same purpose, reducing the amount of interference inside the case in improving the performance of the computer overall.

Ferrite cores are also found on high-end data cables and in many other applications.

Where transformers are concerned, they're found in just about every electrical device that takes power from a wall socket. Inside the large plugs on the ends of most adapters for electric equipment, a transformer changes the voltage or current of the electricity being received and ensures safe operation. These transformers typically include ferrite cores.

What are Ferrites?

A ferrite core is a compound. It consists of oxygen and transition metals. Some of the ferrite cores contain other materials, such as manganese, nickel, zinc and others. Ferrite cores are often designed for a property called low coercivity. This means that the magnetic characteristics of the core can be easily reversed. Ferrite cores that have this characteristic are referred to as soft ferrites.

The most commonly used materials for soft ferrites are manganese zinc ferrite and nickel zinc ferrite. There is a wide variety of other materials in use, as well, which are usually chosen based upon the application, how easy it is for them to accommodate having their magnetic field reversed and other properties.


Applications that use Ferrite Cores

Ferrite cores are used in a wide variety of electronic applications. These are utilized in switching devices, signals applications, transformers and more.

Ferrite cores come in different shapes, such as cylindrical, toroidal and others. They also come in a wide variety of different sizes. These materials are incredibly flexible in this regard and, because they have been being developed for so long, there are many different variations on these materials that are suitable for various applications.

Power transformer ferrite cores tend to work in low frequencies and are physically very large. In electronics, the frequencies tend to be much higher and the transformers tend to be much smaller. Transformers are found in just about every electronic device and, of course, that means that ferrite cores are found playing some role in just about every electronic device out there.

Many ferrite cores -particularly those used in large-scale transformers have accessories associated with them. Cooling systems, for instance, are often employed to ensure that transformers that handle a great deal of power do not overheat, which could damage the transformer and potentially causing even greater danger for anybody nearby.


Overview of Ferrite Products

There are many different products made out of ferrites. Below are listed a variety of these different products and some of their characteristics. It is important to note that ferrite is utilized as a word to describe both completely iron products and products that contain combinations of different chemicals, usually ceramics and iron. Which definition applies depends upon whether magnetics are at issue or materials science is at issue. In the latter case, ferrite generally refers to iron.

Ferrite cores sometimes have to be chosen based upon their compliance with various standards. In such cases, manufacturers typically list which standards the ferrite cores comply with, making it easier for their customers to select the appropriate materials and to ensure that they are designing components with the right specifications.

In addition to their heavy use in transformers, ferrite cores are used in inductors and other components. They are usually included standard on various types of computer cables, though people designing digital data equipment may end up adding additional ferrite sleeves, beads or other components to cables to reduce interference to a specified level.


Ferrite Beads

Ferrite beads are referred to by a variety of different names. They are sometimes called rings, cores, EMI filters and are quite frequently referred to by the name choke. These are passive electronic components. They function to reduce high-frequency noise. This makes them integral parts in preventing interference to or from an electronic device. You'll actually find many of these devices installed at the end of computer cables, housed in a plastic sleeve that has the appearance of a small bump.


Ferrite Core Design Kits

Ferrite core design kits include all the materials that electrical engineers or hobbyists require to design their own ferrite cores. Some of them are sold as purpose specific products, designed to allow an individual to build a given component. Others contain a variety of different materials, which can be used to build whatever components requiring a ferrite core the purchaser needs.

Designers might experiment with different types of cores seeking different properties. The kits allow them to try different materials and designs to customize the components that are being used in any given product precisely.


Ferrite Core Sample Kits

Ferrite core sample kits typically include a variety of different materials, often packaged together for relatively similar purposes. For instance, some ferrite core sample kits include suppression cores and other kits will include different types of cores, which may be required by a designer for various projects.

Some ferrite core sample kits are quite large, consisting of a wide variety of

different options and allowing electrical engineers to experiment with components and different designs. In addition to including different materials of manufacture, ferrite core sample kits quite often contain different designs of cores, allowing them to be utilized for the construction of different types of components.


Ferrite Rings

Ferrite rings come in a variety of different types of cores and are often utilized in broadband transformers. They are also utilized in pulse transformers. These products are also sold to people who are looking to purchase the materials to build a balanced mixer or a choke.


Ferrite Rods

Ferrite rods are used in a variety of different applications, from RFID equipment to inductors. They are often sold as individual components, allowing engineers to customize the components that they use in their designs. Like all other ferrite components, these are available in a wide variety of different materials, allowing engineers to customize the characteristics of the components that they are manufacturing precisely.


Ferrite Sleeves

Ferrite sleeves are quite commonly found on cables, often on cables used with antennas. They help to modify the inductance of the conductor, allowing for better performance from the antenna. These are found in a wide variety of other applications, as well, and are sometimes chosen simply because the sleeve design is the most convenient.


Flat Cable Ferrite Cores

Flat cable ferrite cores provide the same functionality as other ferrite cores, reducing EMI. These particular designs are intended specifically for use on flat cables and ribbon cables. You'll often find these on the inside of data equipment, such as on the ribbon cables and other cables used inside a computer.


Transformer Ferrite Cores

Transformer ferrite cores are among the most common electrical parts in the world. They are utilized in transformers large and small, including being used in transformers, of course, but also being used in inductors. These transformer cores are sold based on the permeability and magnetic characteristics of the devices. Choosing the proper ferrite core for a transformer is among the most important considerations in engineering components.


What does Accessory Type define?

The accessory type of a transformer simply defines what type of accessories are utilized with that transformer during operation. For instance, a silica gel breather is a type of accessory that is utilized to control temperature. Very large Transformers often reach high temperatures during operation and require various accessories for cooling. Other accessories may be used to protect the device in other ways.

Some transformers come with other accessories, such as fasteners so that they can be hooked up to a printed circuit board or other accessories, depending upon their intended usage. What is defined as an accessory will, to some extent, depend upon the vendor from which the transformer is purchased.


What can Transformer Ferrite Cores be used with?

Transformer ferrite cores can be used with any types of transformers, of course, but they are also used in inductors. Ferrite cores are also used in sensors and filters and very frequently in EMI/RFI filters. These are very versatile devices that have a wide variety of different usages and, because they can be manufactured out of different materials that offer different properties, they are incredibly flexible in application and design.


What do you mean by AL rating?

The AL rating applies to how a transformer handles high-frequency current, determining the cutoff frequency. The AL is a nonlinear property and is set as part of the design specification. The AL rating is described as the amount of inductance for every turn that makes up the coil.


What Materials are Transformer Ferrite Cores made of?

There are numerous different materials that transformer ferrite cores are made out of. Some of the most common materials are listed below. The materials out of which a transformer core is made —ferrites—can be described as soft ferrites and hard ferrites. Soft ferrites are able to handle reversals in their magnetic direction without losing a great deal of energy. These materials are also notable because they resist any currents in the core, which makes the more efficient still.

Hard ferrites hold onto their magnetization very well and are very good at conducting magnetic flux. These are inexpensive and, in fact, they are so inexpensive that they are used in everyday applications, such as refrigerator magnets.



F44 is a manganese-zinc ferrite core. These have high saturation characteristics and low loss.


N27 is a material used in power supply devices and in communications equipment. It is also utilized in industrial electronics applications.


N87 is utilized in some of the same applications as N27 cores, and shares its widespread use in communications technology and industrial equipment.