How/Why do magnets destroy hard drives and other electronics?
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Actually (household strength) magnets don’t ruin all electronics. There’s a couple things that magnets are good at trashing though, which got them their reputation.
Magnetic storage – this includes hard drives, tapes (vhs cassette etc) and credit cards. All of these devices work on the same principle: you take something and magnetize only parts of it to make a pattern. Then later, you can move a piece of metal over your thing, “read” the pattern, and thus retrieve data. A magnet coming too close could magnetize the whole thing and wipe out the pattern, destroying data.
CRT monitors – aka your “old style” bulky TV screens. These kind of screens work by firing an electron gun from the back of the device forward, where they strike phosphors and light up to make a picture. A magnetic field can knock the electrons off course, distorting the picture. Magnetizing part of the monitor itself will cause there to always be a field present, permanently knocking the lil duders out of whack.
Most magnets are simply not strong enough to have any effect on a newer hard drive or other newer devices. You need at least 450 pounds of force which eliminates almost all magnets except for some of the strongest neodymium magnets. Some of our newer phones actually have magnets in the speakers.
Hard drives (specifically those that use a disc) store their data on the disc by making tiny magnets on the disk. It can read that data back by measuring the magnetic field it creates in that spot. Another magnet can mess up the hard drive while it’s trying to read, or more dangerously when it’s trying to write to the disc. This causes the data on the disc to be written incorrectly, thus making it unreadable.
Other devices, it varies, but it generally works on the principle that current makes a magnetic field, and conversely a magnet can interfere with a current flowing.
imagine a magnetic storage medium is like a painting. putting a magnet on it would be similar to adding paint to a painting. it won’t look the same after.
in reality, a hard drive is well protected from fridge magnets. but why take a chance?
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