Can magnets damage electronics? It’s a common question, or at least a common belief, especially among people over the age of 30. But the danger that household magnets pose to modern electronics is minimal and grows smaller with each passing year.
While a household magnet can theoretically damage a hard drive, it’s only under unusual circumstances, and more and more electronics are moving away from magnetic hard drives. Household magnets have no effect on computer chips. Household magnets could damage the media older computers used for storage and make CRTs act strange, but that’s where the idea came from and both of these technologies are fading from use.
Why some people believe magnets can damage electronics
In the 1980s, the primary ways computers stored data were on floppy disks or even cassette tapes. These disks and tapes were very sensitive to magnets. So those of us who learned about computers in the 70s, 80s and 90s grew up hearing to keep disks and tapes away from magnets.
There were urban legends of people losing their work by attaching a disk to the refrigerator with a magnet so they wouldn’t forget it in the morning. There’s no doubt this was absolutely possible. Did it ever happen to anyone I knew? No. It was always secondhand. Urban legends could travel even before the Internet, just not as far or as fast.
This advice soon grew well beyond just disks and tapes, even among people who were pretty computer literate. I knew people who labeled their magnetic screwdrivers and refused to use them on their computers, even to do things like disconnect a monitor. But this was an unnecessary precaution. I’ve taken apart hundreds of computers over the decades, and I usually use a magnetic screwdriver so I won’t drop the screws and lose them.
Floppy disks fell by the wayside when USB flash drives became affordable. Magnetic tape is still something large companies use for long-term storage but large-capacity USB flash drives displaced tape backup drives for home use more than 15 years ago as well. For home use, the last bastion of magnetic storage was the hard drive.
But people have long memories. The idea that magnets are bad for computers would puzzle my kids, but not someone who used to carry floppy disks to class or to work.
Strong magnets and CRTs
A strong magnet could cause CRTs to display images incorrectly, either distorting the image or messing up the color. But generally if you had a magnet in close enough proximity to affect the monitor, you’d move it before it could cause permanent damage because the display would be annoying.
If you exposed a monitor to a magnetic field that would affect the monitor even after you moved it, degaussing the monitor with its built-in degauss button would usually fix it.
This isn’t much of a problem today, since flat panel displays have displaced CRTs in televisions and computer monitors. Magnetic fields have no effect on flat panels.
Strong magnets and hard drives
You can erase a hard drive with a strong magnet, as part of a process called degaussing. But this involves strong, powerful electromagnets you don’t generally find at home. If you drop a refrigerator magnet on your laptop, the magnetic force isn’t strong enough to do anything.
Even if you place a household magnet directly on a hard drive case, the metal case will dissipate the magnetic field before it has any effect on the drive’s magnetic platters where it stores the data. If the drive only has a plastic case, the distance between the outside of the case and the platters is enough to protect them.
In the late 90s and early 2000s, expensive CRT computer monitors had a degauss button on them. The degauss button would zap the CRT with a powerful magnetic field to make the monitor recover from display glitches. So for decades, hard drives lived on the same desk as powerful electromagnets, with no ill effect.
If you were to open a hard drive and place a magnet directly on the platters, you’d damage it. But in the process you’d introduce several other problems that are also fatal to hard drives. Any physical contact with disk platters is usually fatal, including exposure to particles in the air. That’s why hard drives are sealed and normally closed with uncommon types of screws, to keep people from opening them.
There are a lot of benefits to moving to SSDs, but the effect of magnets isn’t really a factor.
Household magnets and computer chips
Computer chips don’t use magnetic particles for anything. The heart of computer chips is silicon, the main element in sand. There are metallic connections inside and between chips, but these connections aren’t iron or any other magnetic metal. They’re usually copper or another highly conductive metal. Iron conducts electricity better than nonmetallic elements such as carbon, but as far as metals go, it’s not a great conductor. There’s no reason to use them in computer chips, and even if you did, magnetism doesn’t affect their ability to conduct.
Computer chips don’t store data as magnetic particles, so a field from a household magnet has no effect on them.
This doesn’t mean I haven’t heard stories. I heard plenty of stories, especially in the early 90s, about how someone’s neighbor’s uncle damaged their computer by using a magnetic screwdriver to work on it. But I never met anyone who had a problem firsthand. And I never heard these stories from other computer professionals. If someone’s neighbor’s uncle really did damage their computer, it was probably because of damage from static electricity. They just happened to be using a magnetic screwdriver. And if they never felt a static discharge, they’d be more likely to blame that magnetic screwdriver for the problem, since the prevailing wisdom at the time was that magnets are bad for computers.
Apple uses rare-earth magnets for its power connectors, since it holds well under normal use but will break away under stress, unlike a traditional barrel power connector. If magnets harmed computer chips, Apple wouldn’t be able to do this.
Can magnets damage phones?
Will a magnet harm a cell phone? There’s nothing in a smartphone that a household magnet will affect other than the digital compass in the phone. Even in that case, the effect will be temporary. Your phone will give you a warning and you can reset the compass to reverse the effect. The most likely way to damage a phone with a magnet would be to drop a magnet on it that’s big and heavy enough to crack the plastic. That’s unlikely.
In theory a strong enough magnet could affect the phone’s speaker, but again, such magnets aren’t household items.
Do magnets affect video cameras?
Household magnets could certainly affect video cameras that store their video on magnetic tape. They’ll damage the tape, even though their effect on the camera itself will be negligible or non-existent. But magnetic tape even for video use is less and less common today.
A strong enough magnet could affect the speaker in the camera, but these types of magnets aren’t something that people encounter in ordinary circumstances. Today, a camera is more likely to sustain damage from a laser pointer than from a magnet.