Maintaining Impedance in High-Permeability, Split Core Ferrites for Low-Frequency Applications

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Ferrites are ceramic components that can be used to suppress electromagnetic interference (EMI) in certain applications. This presentation will discuss the basic properties of solid round ferrite cores, the impact an air-gap can have on the performance of these cores, and special considerations. In particular, this discussion focuses on the use of high permeability materials, such as Fair-Rite’s 75, in low-frequency suppression applications since its permeability is relatively high compared to other soft ferrites used for this purpose, making the effect of an air-gap much greater.

Who Should Attend?
Engineers interested in solving low-frequency EMI issues in their cable designs.

Rachael ParkerSpeaker: Rachael Parker
Ms. Parker became Vice President in July 2014 at Fair-Rite Products Corp. Although she oversees many operations within the company, Rachael is focused primarily on the marketing aspect of the business. She has experience in product design, project leadership, and program management from her time at 3M and Oracle.

Rachael holds a Bachelor’s degree in Electrical Engineering from University of Rochester, a Masters degree in Electrical Engineering from Cornell University and a Master’s of Science in Engineering Management from Tufts University.

The following are questions presented to the speaker by the attendees during the webinar, along with answers to each.

Is it possible to cover two frequency ranges by putting two different mix ferrites in series?
Answer: Yes

How do you actually measure the parameters of ferrite components?
Answer: Depends on the parameters being measured. For the more standard testing (impedance and inductance) we use Keysight impedance analyzers (E4991) and HP/Keysight LCR meters (4284/4285).

How are you able to tune the various materials?
Answer: Our R&D department has the ability make custom formulations and process changes depending on the desired properties of the material.

How does humidity affect ferrites?
Answer: Excessive humidity can effect some material properties. Examples include reducing the resistivity of the material as well as degrade the Q. How great of an effect is observed depends on the porosity of the material. Less dense materials such as our 60 series will see a greater effect than something more dense like our 44 material.