Wiring and componentsQuestion 875 of 1506

A ferrite ring is placed around signal wires to reduce high-frequency noise. How does it work?

It uses up energy overcoming the ferrite's hysteresis.
It grounds the noise through the ring to the frame.
It adds capacitance that stores the noise forever.
It blocks the magnetic field with a layer of copper.

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Correct answer: It uses up energy overcoming the ferrite's hysteresis.

The ferrite takes energy from fast voltage surges, so their strength is reduced.

Source: Lessons in Electric Circuits I: DC (Kuphaldt), 14.4: Permeability and Saturation

Questions last reviewed: 18 October 2026

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