Magnets and Electronics

[feppytweed]

can a neodymium magnet thats the size of a large hockey puck mess up or ruin cd's or laptops or watches? anything electronic?

[friedo]

CDs are plastic, so magnets won't mess them up. Magnetic storage (hard drives, floppies, videotapes, etc) can be hardily screwed by a magnet. Anything with small metal parts (mechanical watches, etc) can potentially get screwed up if the magnet yanks stuff around inside.

[Nanoda]

Yeah, any optical media are going to be fine, and I wouldn't take any great care with my digital watch around a magnet, though if I had a more expensive mechanical one, I'd take note. Certainly touching something metallic on a laptop with something like that could affect the HD inside. If it's quite strong, you could permenantly mess up your television or CRT.

[Mangetout]

Would a hard drive be affected? They are usually shielded aren't they?

One thing your magnet will screw up is the magnetic strip on credit cards - I discovered this to my cost when I idly put a very powerful magnet (which I took out of an old hard drive) in my pocket.

[mks57]

Would a hard drive be affected? They are usually shielded aren't they?


They aren't shielded against magnetic fields. That is usually done with Mumetal (5% Copper, 2% Chromium, 77% Nickel, and 16% Iron).

[Desmostylus]

Would a hard drive be affected? They are usually shielded aren't they?Yes, they're shielded, but not heavily. You can buy erasers that will wipe out hard drives:

http://www.datalinksales.com/degaussers/hd1.htm

[Desmostylus]

Also note that the eraser I linked to above states a field strength of 4,350 Gauss.

A tiny neodymium magnet can match that:

http://www.gaussboys.com/product_info.php?cPath=&products_id=37