Electronic – the use of magnets around electrical cables

power supplywire

I haven't seen any for a while now, but a couples of year ago I saw some several times: cylindrical magnets around electrical wires. I'm not talking about specialized equipments but items of everyday life which comes with such a magnet. In fact I did not know it was a magnet until I accidentally broke one. Unfortunately I did not manage to find any picture from the web.

Do you know the use of them? Also, are we still using them?

Best Answer

They're not actually magnets, but rather ferrite which is a paramagnetic material. A ferrite bead with a conductor through it is an inductor and so is used as a low pass filter. Typical use is for power cables to reduce EMI (electromagnetic interference).