Some time ago I came across content where a design engineer experienced a strange occurrence. He had inserted ferrite bead in a circuit. What resulted out of this took him by surprise. The ferrite bead actually worsened the noise condition. The ferrite bead which was supposed to have suppressed unwanted noise had actually increased it. The occurrence had confused many who are dealing with EMI cases. A Ferrite Bead Coil is a high inductance material used in electrical components.
Ferrite beads used in coils act as major impediment against very high frequency noise. The bead manufacturers ensure that the ferrite beads should possess higher impedance power against noise of very high frequency range. These beads which have high inductance power are capable of averting a part of noise energy. The rest is allowed to pass through. This is an electrical component acting as a resistor against noise energy. It actually absorbs noise from the electrical circuit with the help of a heating process.