Ferrite Bead
May 16, 2011

Ferrite bead is a frequency dependent resistor and is used to help reduce unwanted noise. At low frequencies, inductive impedance is 10 ohm or less and the attenuation to the low frequency signal is limited. At higher frequencies, the impedance increases to over 100 ohms and becomes resistive above 100 MHz. The resistive loss attenuates noise at unwanted frequencies through heating of the bead’s ferrite material due to eddy currents.