Ferrite bead

  A ferrite bead is a passive electric component used to suppress high frequency noise in electronic circuits. Ferrite beads employ the mechanism of high dissipation of high frequency currents in a ferrite to build high frequency noise suppression devices. Ferrite beads may also be called ferrite cores, ferrite rings, ferrite EMI filters, or mistakenly as ferrous beads. Engineers often jokingly call them FCC goobers, or FCC lumps after their shape when attached to a cable.

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Overview

Ferrite beads are similar to inductors in some ways but work especially in an area that is parasitic for general purpose inductors. They essentially act as a high impedance, or "resistor" to high frequency EMI/RFI electronic noise. The absorbed energy is converted to heat and dissipated by the ferrite, but only in extreme cases will the heat be noticeable.

Ferrite beads are one of the simplest and least expensive types of interference filters to install on preexisting electronic cabling. For a simple ferrite ring, the wire is simply wrapped around the core through the center typically 5 or 7 times. Clamp-on cores are also available, which can be attached without wrapping the wire at all.

A list of some ferrite bead vendors

• API Delevan Inc
• JW Miller A Bourns Company
• Murata Manufacturing
• Panasonic - ECG
• Steward
• TDK Corporation
• Taiyo Yuden
• Tyco Electronics
• Fair-Rite
• Strontium Ferriten India Limited

See also

• balun
• Choke (electronics)
• Electromagnetic interference
• Ferrite (magnet)
• Magnetic core
• toroid
• Unintentional radiator