What computer components are currently vulnerable to magnets?

Question

When I first started using computers, law of the land in computer class was never bring magnets near anything computer related, lest you lose all your data or screw up your monitor.

Now I am pretty sure magnets will still royally mess up a standard hard drive, and I know for a fact they screw up a CRT monitor.

Though I am also pretty sure they do not screw up a LCD monitor?

Now I have my phone which uses magnets to determine if it's docked, and it made me wonder.

Is it the power of the magnet preventing data loss or the sheer fact that whatever memory type in the phone is immune to it?

What about ear buds, as I know those have tiny magnets in them. Are those capable of damaging any electronic device currently in use?

I'm wondering if I'm being paranoid, but I really am not sure what magnets will damage and what they won't!

Is there a list, or rule of thumb for determining what will be hurt by magnets and what won't be?

Answer 1

Hard drives, RAM chips, power supply, anything electrical can be vulnerable to magnetic fields.

In common practice it's not all that harmful unless you're doing it on purpose. Case in point is the magnet MacBooks come with built in to use with the power supply.

Answer 2

A list or rule? Sure, anything that uses electro-magnetism to function could, and would be affected by magnets. The question is what the detrimental effects, if any, would be and how strong and close do the magnets need to be. Generally the two most questioned items are the monitor and disk drives.


LCD/LED monitors are not generally susceptible to magnetic interference like CRTs are because they function completely differently (remember, CRTs use magnets to deflect the electron beam, so an external magnet would obviously mess with that).

Hard-drives are also not affect by magnets because of the way they function. You can research the details on how hard-drives work for a more thorough understanding, but the easy answer is that there is a very powerful magnet inside each hard-drive that controls the read-write head’s movement. That’s why some people like to rip open dead drives to get at the sweet, gooey super-strong magnet inside. If that magnet that is inside the drive, and right beside the platters doesn’t wipe them, then any magnet that you are likely to have around isn’t going to.

As for flash drives, they are a different technology altogether so they are not going to get erased.

There is one component however that is indeed affected by magnets that most people miss: cables. While many cables are shielded, some are not and thus susceptible to a magnetic field. For example, a cable connecting the sound card to the speaker may be shielded, but the little cable connecting the CD/DVD drive to the sound card usually isn’t and ingress of a magnetic field could cause interference. Or, while rounded IDE cables (especially for IDE133) are usually shielded, ribbons usually aren’t and even at speeds of 66/100 could be affected enough to cause some corruption or at least reduce performance due to re-tried reads/writes.


I would say that modern systems are not really vulnerable anymore because as time progresses, science and knowledge advances, but unfortunately that’s not sufficient. While that may be true, in the old days things were done right a lot more than today with all the cut corners and cost-reducing measures (eg NVIDIA’s “Bumpgate”).

Anyway, the point is that when it comes to modern computers (I’m counting floppy disks as not-modern), you don’t really need to worry about magnets. You can breath a sigh of relief. :)

Answer 3

If it's electric it can be affected my magnets.

That said most electronics today is pretty well shielded so if you don't stick your magnet to stuff or let it rub against it for a prolonged time you should be pretty safe.

And your phone does not use magnetism to store data on a disk, it uses an internal flash card.

The only thing that I can think of that could (in a reasonably scenario) be hurt by a magnet is floppies and cards with magnetic strips.

This is of course with normal household magnets.

Answer 4

You're being paranoid. It would take a pretty significant magnet to permanently affect most parts of a computer these days. As long as you're not working around industrial magnets, or sticking things to the side of your case with powerful rare earth magnets, you should be fine.

Answer 5

I've passed a standard size 512GB HDD through a magnet strong enough that I couldn't pull a chunk of metal off it, and it functioned absolutely fine afterwards (And does to this day, as far as I know) - I think it's safe to say hard drives aren't that susceptible anymore.

(CW because this is, obviously, not proof of any kind, just my experience. I do not endorse the using of magnets on 512GB HDDs, use them to store media or something if you really don't want it :P)

Answer 6

There's a similar question on Yahoo! Answers:

Do Magnets damage Electronics?

Answer 7

At my work we found an old floppy disk with a pretty powerful magnet stuck to it that'd been that way for years. I could still read off the floppy just fine.

Answer 8

Rarely a problem anymore. Higher bit-density requires higher coercivity, which results in greater resistance to "accidental" magnetism. Old single density floppies could be wiped out if you ran them over with a vacuum cleaner. Newer hard drives are quite resistant to erasure from anything you're likely to have laying near the computer at home...

Answer 9

hard drives and crt would probably be mostly severely affected.

i suspect the most would need some kind of modulating magnetic field to create sufficient inductive properties

Answer 10

From my experience, very little damage can be expected unless you get a strong magnet near an unshielded coil of some sort that's on a circuit board. This can significantly disrupt the magnetic field that surrounds this component, at least enough to change the voltages that it is involved with cleaning or adjusting. It most likely won't 'fry' a circuit, but it could cause it to over-heat due to voltage changes which could lead to component damage and board failure.

Case in point, I added a strong magnet to the bottom of a USB hub so it would stay in one place on top of my computer case. After a while I noticed that it was getting significantly hotter than the exact same hub that didn't have a magnet attached to its base. After removing the magnet, it went back to normal fortunately.

Contrary case: I have a terrific battery tester, 'Batt-O-Meter', that "loads" the battery being tested, then processes some additional information to give you not only the actual voltage (in digital form), but it also indicates the effective percentage of power left in the battery, a more significant factor when you're considering how much longer a battery will last, or how efficient your rechargeable batteries are at being charged.

I attached the magnet to the main 'positive' post on the device so any battery I'm testing will stay connected to that post with little effort by me while I'm using both hands; one to press a button and hold the battery, while holding the wired probe against the 'negative' post. I've been checking whether there has been any deviation of the resulting readings due to the magnet and so far there hasn't been, and of course, no over-heating as in the other case.

There's no way to tell how much interference will occur until you do a trial with and without the battery in the vicinity of the device. Momentary exposure will surely not hurt most circuits.