Ferrite beads have been around for some time now and are being widely used in low power and signal lines. It stands to reason that ferrite beads could be very useful in combating EMI in switch mode power supplies. And yet, the penetration of the beads to the switch mode converters design is rather slow. This is not surprising considering the fact that the incorporation of a ferrite bead into an electronic design is far from being simple, to say the least. This is primarily because there are virtually no analytical or simulation tools to aid the designer in predicting how the beads will behave in the real circuit. It is rather frustrating that even a simple task as cleaning a power line needs trial and error. And even more baffling is the fact that if the (undefined) “wrong bead” is put into the design, EMI situation gets worse. As a result, experience, intuitions and trial and error are the only practical means that can be applied today. This is rather pity since the inherent properties of the ferrite beads are really remarkable and they can be extremely helpful not only to clean power lines but probably in FET transistors drive, control lines and others. For a primer on ferrite beads in power electronics see: https://youtu.be/F-wSu162tCo