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?

Solution 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.

Solution 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 affected 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. :)

Solution 3

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)

Solution 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.

Solution 5

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...

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Comments

[dmckee --- ex-moderator kitten]

I recall sitting at a computer on a major particle physics experiment when the big (10x5x3 meters, >100 tons) dipole magnet was being tested about 40 meters away. As they ramped it up the display would twist to one side by about 10 degrees. Hit "degauss" on the monitor front panel, ::blur:: then return and all would be well. Later, they'd ramp down, and the monitor would twist the other way...good times. Leave you wallet in your pocket and walk into the hall while they were doing that and you'd loose the data on the magnetic stripes on all your cards...bad times.

[Brett Allen]

Thanks everyone for your answers, really helped me gain a better understanding.

[Shawn]

Nobody has talked about these yet: Cars (and their contents ie gps, radio, etc), tools (chainsaws, drills), kitchen appliances, ceiling fans, etc. Any caution to take with those? Also, could a magnet induce enough magnetism in another metallic object to make that object dangerous? And lastly but mostly, are there any methods of avoid the negative effects of magnets ? (such as enclosing them in a faraday cage or something like that). Sorry for highjacking your question Aequitarum, but mine was closed as a duplicate..

[osodyj]

@Shawn The normal magnets you will find around an average house will not do much to modern electronics for reasonable exposure levels (there is an exception for particularly senstive things like floppy disks, and CRTs). So, an average consumer does not need to worry about it. For your not so average consumer, Wikipedia has a good write up at en.wikipedia.org/wiki/Magnetic_shielding

[Daniel R Hicks]

Stick any computer component inside an MRI machine and you can kiss it bye-bye.

[quack quixote]

weak magnets + good shielding = no problem. strong magnets + unshielded hdd = bye-bye data.

[hotei]

@quack: Every hard drive I've ever taken apart had 4 strong (rare-earth) magnets inside that help move the arm with the read heads back and forth. What you need to harm a HDD is a magnetic field (not a permanent magnet) so strong that it takes 5 minutes of 120 volt current to charge the capacitor that discharges through a coil in less than a millisecond to create the magnetic field to wipe the drive. These machines cost a ton of money. A hard drive inside a metal case is pretty safe - until you put it in one of these.

[John Sonmez]

Seriously, how does this answer not get voted up. +1 For pointing the authoritative source on the matter. I bow to you sir, well done.

[Mark Booth]

@John - Link only answers aren't useful as links often go stale.

[John Sonmez]

Not this one.. This one is Yahoo answers. YAHOO, seriously.

[osodyj]

It is about the strength, duration of exposure, and relative motion of the magnet with the harddrive. Weak magnets will generally not do anything, relative strong magnets for a short time won't do much. A strong magnet, for a longer period of time, especially if it is in motion relative to the electronics will corrupt the data (and a really strong magnet in motion for a long period of time can fry just about any unshielded electronics.) (Edit for clairty: By strong I mean far stronger than most people have lying around. Even old harddrives are more reiliant than most people think.)

[osodyj]

@JohnSonmez I am not sure I would call Yahoo! Answers authoritative. With that said, it is a useful link, +1.

[Synetech]

I think that John was being sarcastic.

[psusi]

This is completely false. Hard disks care because they rely on magnetic fields to store your data. Most electronics, including ram and power supplies don't give a flying fig.

[aidan]

I'm a little concerned about your assertion that HDDs are immune to strong magnetic fields. They do indeed contain very strong rare-earth magnets, but they are aligned in a particular way, and shielded so that most of the magnetic field is contained. In other words; I'll let you try running a magnet over the surface of the disks first! :)

[Synetech]

@aidan, it has been discussed in numerous places countless times and the consensus is that anything short of a very powerful magnet (I recently read about a company that sells super electro- and permanent-magnets that can wipe drives, but I don’t remember where) will not likely do much to a hard-drive. I clearly said that any magnet that you are likely to have around (i.e., fridge, speaker, shower-curtain, etc. magnets) won’t have an effect (at least not by accident; opening the drive and swiping the magnet directly on the platters is not what this question is asking).

[Anonymous Penguin]

I heard that the best way to decorate your computer is to put hundreds of super strength magnets on the case!!!!! No. As long as you're not dumb or trying to destroy your computer, I doubt that anything bad would even be possible.

[Luke]

@psusi you are obviously not aware of electromagnetic induction.

[psusi]

@Luke, I am well aware of induction, but we are talking about permanent magnets here, which is a completely different animal.

[Luke]

@psusi What? If an electrical conductor (copper tracks on a PCB) and magnetic field move relative to one another, a current is induced in the conducting material.

[psusi]

@Luke, yes, and do you have any idea how weak of a current that is? I deal with this kind of induction in multi Tesla MRI scanner magnets where it actually is a problem. You aren't going to get within 4 orders of magnitude to that with a fridge sticker or magnetized screwdriver even if you do rotate it at a few hundred rpm right next to the drive.

[NSAutomaton]

Just curious-what was on the disk?

[jbowman]

@JohnSonmez You said it man; the only source of information more authoritative than a Yahoo answer is a meme or anecdote posted on a Facebook wall. It seems your mockery has been utterly and hopelessly lost on the two responders to your comments.

[RCross]

This should really become the accepted answer - the currently accepted answer does not sufficiently answer the question.

[Nikana Reklawyks]

I'm interested in sticking things to my case with rare earth magnets, do you know how large a magnet applied to what parts of the case could deal real damage ?

[Sarita]

It was a DOS boot disk used for Ghostcast.