Ferrite Core Transformers- Types & Applications

What are Ferrite Core Transformers?

Ferite core transformers are  made from ferrite core is also known as  ferrite core transformers. The ferrite core transformer is used for higher frequency applications.The power transformer is made out of CRGO steel core which operate at 50 or 60 Hz frequency.

The transformer operating at higher frequency is designed with a ferrite core. The composition of ferrite core in transformer is iron oxides,combined with nickle, zinc and manganese compounds. These compounds have low coercivity  and also called soft ferrites.

Advantage of use of  Ferrite Core Transformer?

A major advantage to a ferrite core is its high electrical resistance to high current. The high resistance to eddy current lead lower eddy current losses over many frequencies.

Ferrites have an advantage over other types of magnetic materials due to their high electrical resistivity and low eddy current losses over a wide frequency range. These characteristics, along with high permeability, make ferrite ideal for use in applications such as high frequency transformers, wide band transformers, adjustable inductors and other high frequency circuitry from 10 kHz to 50 MHz.

Its high permeability adds to its ideal combination for use in high frequency transformers and adjustable inductors. In fact, the high magnetic permeability along with  low electrical conductivity of ferrites helps in the prevention of eddy currents and thus eddy current losses decrease. A lack of eddy currents and consistent performance at high frequencies makes these cores ideal for RF transformers.

One disadvantage when working with ferrite is it brittleness. Compared to metal cores, this core is more likely to be damaged from drops and bangs. Powder cores are stronger than ceramic cores, but weaker than metal.

Types of Ferite Core Transformer

  • Manganese Zinc Ferrite (MnZn) – useful for inductors up to 70 MHz
  • Nickel Zinc Ferrite (NiZn) – Higher resistivity than MnZn, useful when frequency range is from 2MHz to MHz in the several hundreds and ideal for inductors over 70 MHz

Temperature and permeability play huge roles in ferrite core selection, since ferrite materials begin to lose magnetic capabilities under 500 degrees Celsius. Ferrites are also classified by shapes such as:

  • E, I Cores – easy to construct with simple bobbin winding, making them useful for power and telecom inductors, along with broadband, converter and inverter transformers
  • ETD Cores – center post has minimal winding resistance, ideal for power transformers and inductors
  • EFD Cores – made with cross-sectional areas provide utility for compact transformers
  • EER Cores – based on a round center post, providing a shorter winding

Applications of Ferrite Core Transformer

The ferrite core transformer is used  as Converter and Inverter Transformers, Differential Mode Inductors, Power Transformers, Pulse Transformers, and Telecom Inductors.