What Is the Purpose of Ferrite Bead? How Does It Work and How Do You Choose the Right One?

Within popular electronic products such as laptops and mobile phones, ferrite beads reduce high-frequency noises. A ferrite bead serves the technical purpose in a circuit as a low pass filter, meaning it allows only low frequencies while blocking others. It attenuates high-frequency electromagnetic interference (EMI) as part of the ferrite bead purpose.

Ferrite Bead Purpose

In terms of noise reduction, the purpose of the ferrite bead is to attenuate or reduce high frequencies. The two types of ferrite beads are chip and wire-wound. Chip ferrite beads provide less control for attenuation and frequency range. On the other hand, wire-wound ferrite beads have lower DC resistance and higher current ratings. They also offer wider options for attenuation and frequency range.

Purpose of Ferrite Cores on Cables

Ferrite beads prevent a cable from acting as an antenna, which can otherwise pick up EMI from household appliances. Data cables and medical equipment cables are particularly sensitive to interference, which is why large ferrite cores are needed on external cables.

Related: Ferrite bead Vs. Inductor: All You Need to Know

What Does a Ferrite Bead Do?

What does a ferrite bead do on a cable? A ferrite bead is a passive power supply device that suppresses high-frequency signals. It dissipates RF energy in the form of heat, based on Faraday's law of electromagnetic induction regarding how current moves through a wire. Here are different reasons why ferrite beads are used in circuits:

  • Cuts noise in a power supply line
  • Enhances signal integrity in electronic equipment
  • Suppresses EMI in TVs, computers, gaming systems, and audio gear
  • Designed for transformers, high-frequency conductors, and antennas
  • Protects electromagnetic devices from interference

How to Choose a Ferrite Bead

Some people get mixed up by all the different names for ferrite beads, such as ferrite choke, ferrite block, and EMI filter. Ferrite beads can be added to cabling to reduce interference. They are typically the most affordable solution for filtering unwanted frequencies.

Also read: Ferrite Core Inductors: All You Need to Know

Key Concerns

One of the most important concerns about ferrite beads is how they are sensitive to temperature. They can get damaged at a certain DC current level. When the cable acts as an antenna, it must comply with FCC regulations to reduce EMI. The amount of resistance loss generated by ferrite beads and frequency filtering range should be taken into account for each specific application. The selection of ferrite beads should be based on impedance versus load current metrics.


Learning the ferrite bead's purpose gives you a clear concept of why this common device is used in a wide range of popular electronic equipment. The device, which can be added to an inductor, dissipates RF energy to heat within a coiled wire. If you need a ferrite bead, visit the Allied Components International website today to view our catalog.

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Allied Components International

Allied Components International specializes in the design and manufacturing of a wide variety of industry-standard custom magnetic components and modules, such as chip inductors, custom magnetic inductors, and custom transformers. We are committed to providing our customers with high-quality products, ensuring timely deliveries, and offering competitive prices.

We are a growing entity in the magnetics industry with 20+ years of experience.