In Focus: The Ferrite Bead

 

A ferrite bead is a passive electric component that suppresses high frequency noise in electronic circuits. It is a specific type of electronic choke. Ferrite beads employ the dissipation of high frequency currents in a ferrite ceramic to build high frequency noise suppression devices. Ferrite beads may also be called blocks, cores, rings, EMI filters, or chokes

Large ferrite beads are commonly seen on external cabling. Ferrite beads are one of the simplest and least expensive types of interference filters to install on pre-existing electronic cabling. For a simple ferrite ring, the wire is simply wrapped around the core through the centre. The introduction of the ferrite core around the wire increases the wire’s self-inductance, and thus still absorbs energy from noise in the wire.

Ferrite beads prevent interference in two directions: from a device or to a device meaning that the energy is either reflected back up the cable, or dissipated as low level heat.