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Can a cell phone or iPhone's magnet in speakerphone or microphone affect or corrupt data on a hard drive on notebook computers?

Sometimes we place a cell phone or iPhone next to the side of a notbook or on top of a notebook's keyboard area. Since there are magnets in the speakerphone or microphone inside a cell phone, will that potentially affect the hard disk in the notebook?

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up vote 4 down vote accepted

I suppose there's a theoretical risk, but I don't think the magnets in small speakers are strong enough to affect hard drives - unless there was something wrong with hard drive. You might just have a problem if you put a top of the range hi-fi speaker (something from B&W or B&O springs to mind) right next to the hard drive, but you'd have to take the speaker out of the cabinet first.

Magnetic fields obey the inverse square law in that doubling the distance from the speaker will reduce the field strength by a quarter, so the magnetic field doesn't extend very far at all.

I would also imagine that notebook and hard drive manufacturers have thought of this and ensure that there's no problem here.

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Absolutely not. We would all be in trouble if the minute magnetic field in a cellphone could wipe your harddrive - in fact, the harddrive has a more powerful magnet that moves the head than is in your phone!

As noted by Daniel Rutter at Dan's Data, magnetic fields falls roughly with the inverse cube of the distance.

Also see this article - scroll down to "The enemy within", his answer to a question about the 'danger' of the PC speaker magnet in a computer.

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There are (relatively) huge magnetic fields surrounding a HDD, you can run a standard size magnet right over one and it'll do nothing at all (much to my dismay last time I tried!), something from a phone is perfectly safe.

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