Why ferrite material only passes low frequency and blocks high frequency. I mean what's going inside this material which is leading to show such frequency characteristics?
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$\begingroup$ Are you asking about a ferrite core with the wire wrapped around it, or a ferrite bead? I ask because the mechanisms are different. $\endgroup$– John RennieCommented Oct 21, 2022 at 6:12
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$\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$– ZaellixACommented Oct 21, 2022 at 8:13
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1 Answer
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Ferrites are highly customizable materials. Some are made to be lossy to serve as high frequency filters, others are formulated to minimize losses in high quality filters or power system components. Lossy ferrite beads are often slightly conductive materials and they cause eddy current losses. One can achieve similar functionality at low and medium frequencies by combining a (mostly) lossless inductor and a resistor in a parallel circuit and the lumped circuit models of ferrite beads reflect this by approximating the component with a parallel LRC circuit. The impedance of a lossy ferrite bead therefor shows a (usually fairly wide) resonance that can be tuned from hundreds of kHz to GHz by choosing the material's permeability and resistivity. I am certain that at least some materials have additional loss mechanisms that are due to microscopic magnetic properties but if they do, then the effects are, at least in my personal experience, not easily distinguishable from eddy-current losses at the technological level.
