I'm designing something that involves a small magnet, probably about 0.5m in diameter, which will rest next to a computer wire carrying data, video, audio, etc. If the wire is insulated (think USB or VGA cable), will the magnet have any adverse effect on the current flowing through it?




I don't think that the fact that the small object you're placing next to a computer cable has a DC magnetic field has any significant effect on the signal currents. However, the fact that the small magnet may have a very large magnetic permeability (as most permanent magnets do) could add significant inductance to the circuit and tend to cause it to act as a low-pass frequency filter in some situations and like a common-mode rejection filter in other situations (Ferrite Core terminators) depending on the exact placement of the small object with respect to the signal cable.

Probably best to keep it and any other high magnetic permeability objects away from the signal cables.

  • $\begingroup$ Thanks for your answer! How do I measure the permeability of the magnet? Will just knowing the mass and dimensions of it help calculate it? $\endgroup$ – Carpetfizz Oct 21 '15 at 19:07
  • $\begingroup$ @Carpetfizz- The permeability is an intrinsic property of a material and doesn't depend on the dimensions of the material. Probably by far the easiest way to get the permeability is to find out what material the magnet is made of and then look up its permeability for the characteristic frequency of the signals being carried on your wires. $\endgroup$ – user93237 Oct 22 '15 at 2:04

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