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Old 07-13-2008, 11:20 AM   #1
thesimson01
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Memory card VS magnet

Is somebody knows if a magnet can damage a camera memory card (like sd card)? Ex: loosing picture in it..
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Old 07-13-2008, 11:30 AM   #2
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Originally Posted by thesimson01 View Post
Is somebody knows if a magnet can damage a camera memory card (like sd card)? Ex: loosing picture in it..
Based on the information in this article, Making The Most Of Digital Camera Memory Cards , it appears that the answer would be no, which surprised me.

Fred
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Old 07-13-2008, 11:36 AM   #3
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I know of two people that lost their memory cards due to magnets. It wipped out everything and the card was useless. That areticle that Abby's dad posted mentioned the magnets on the exray rollers not harming it. That is try because tat are not so strong. If they were it would wipe out the data on all the laptops that went through them.

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Old 07-13-2008, 12:44 PM   #4
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I know of two people that lost their memory cards due to magnets. It wipped out everything and the card was useless. That areticle that Abby's dad posted mentioned the magnets on the exray rollers not harming it. That is try because tat are not so strong. If they were it would wipe out the data on all the laptops that went through them.

Dan

Googling memory cards and damage, there are tons of articles on the internet that reinforce the fact that magnets cannot harm memory cards - they are an electronic storage media, not magnetic. The instances they cite where it MIGHT be possible to damage a memory card would involve high amounts of magnetism rapidly turned on and off, such as with a large electric magnet, which would produce its own electric current, or a very large magnet, such as an MRI machine, which would destroy it, possibly for a similar reason as the previous example. The basic answer is that while magnets will erase floppies or hard drives, they don't touch flash-type (electronic) memory. They do say that they are susceptible to many common errors, such as dirt, the accidental drop of water, excessive heat, etc. Another link, maybe clearer than the other. Other than that somehow the data vanished from the memory cards mentioned above, do you have any proof that it was from magnets, and if so how were they exposed to such high magnetic forces? Just curious, mostly because my first gut feeling, before I started actually looking for an answer, was that magnetic exposure would be highly undesirable.

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Old 07-13-2008, 01:45 PM   #5
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Testing

I just took a 32 meg memory card that came with a camera (why do they bother?) and loaded it with some JPGs. I then took a relatively strong hand held magnet from our childproof locking system. It's not a super-powerful electromagnet, but if you stick it on something it's rather hard to pull it off.

For my test, I set the memory card on the magnet. I rubbed the memory card with the magnet. I banged on it with the magnet. I tried both sides. I tried rubbing the metal contacts with the magnet. I even gave it the evil eye while holding the magnet.

The result - all of the data was still perfectly readable. Maybe I was lucky. Maybe my magnet was too weak. Maybe it was the wrong type of magnet. Maybe it did grievous long term harm to the memory card that will cause it to burst into flames with my next use. I'm guessing, however, that it didn't do any real damage at all.

My conclusion - if magnets harm memory cards, the effect is pretty darn small. Microdrives are an entirely different story.
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Old 07-13-2008, 01:50 PM   #6
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I have used jump drives around a MRI area with no issues now get too close to a xray machine and I had issues with my watch dieing and credit cards.

Flash memory should not be affected by most magnets you are going to come in contact with they do not align metal particles like audio tapes and floppy disk and hard disk drives they use memory chips.

Each memory chip on a module contains millions of transistors and capacitors, which combine to store a single bit of data in a memory cell. The capacitor acts as a holding cell for the data, which is either a 0 or a 1, and the transistor allows the memory circuitry to read or change the value of the data held in the capacitor.
http://www.upgradememory.com/How_Doe...__W8C15775.cfm
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Old 07-13-2008, 01:51 PM   #7
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There's always a lot of mysterious tales floating around the internet about magnets - look at all the disgusting crooks who sell magnetic bracelets and such with the lies that they'll somehow make you healthier, when it's been disproved countless times. (Sorry, health scams are a big pet peeve of mine. Those people are the lowest of the low.)

Anyway, the only stuff that magnets should affect is magnetic media, like floppy discs, cassette and video tape, etc. You're more likely to hurt a memory card by dropping a magnet on it than by the magnetic fields.

Mark, it's worth noting that the danger to microdrives isn't that the magnets are wiping away your data, it's that you could cause the heads to crash into the platters. Hard drives already have pretty serious magnets inside them already, I've taken apart several and the magnets inside are very strong!
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Old 07-13-2008, 01:56 PM   #8
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There's a PC World article here BTW about PC myths. As with everything on the internet, you should always question things unless you read them in multiple independent places, but he's right about this. (I do question a statement farther down in the page of someone actually damaging an external drive by disconnecting it while it was writing - you can certainly screw up the data but I am extremely skeptical about causing physical damage in this way.)

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For venerable floppies, this statement holds true. We placed a 99-cent magnet on a 3.5-inch floppy for a few seconds. The magnet stuck to the disk and ruined its data.

Fortunately, most modern storage devices, such as SD and CompactFlash memory cards, are immune to magnetic fields. "There's nothing magnetic in flash memory, so [a magnet] won't do anything," says Bill Frank, executive director of the CompactFlash Association. "A magnet powerful enough to disturb the electrons in flash would be powerful enough to suck the iron out of your blood cells," says Frank.

The same goes for hard drives. The only magnets powerful enough to scrub data from a drive platter are laboratory degaussers or those used by government agencies to wipe bits off media. "In the real world, people are not losing data from magnets," says Bill Rudock, a tech-support engineer with hard-drive maker Seagate. "In every disk," notes Rudock, "there's one heck of a magnet that swings the head."
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Old 07-13-2008, 03:16 PM   #9
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Thanks you all for these infos.
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Old 07-15-2008, 11:52 AM   #10
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Quote:
Originally Posted by Abby's Dad View Post
Googling memory cards and damage, there are tons of articles on the internet that reinforce the fact that magnets cannot harm memory cards - they are an electronic storage media, not magnetic. The instances they cite where it MIGHT be possible to damage a memory card would involve high amounts of magnetism rapidly turned on and off, such as with a large electric magnet, which would produce its own electric current, or a very large magnet, such as an MRI machine, which would destroy it, possibly for a similar reason as the previous example. The basic answer is that while magnets will erase floppies or hard drives, they don't touch flash-type (electronic) memory. They do say that they are susceptible to many common errors, such as dirt, the accidental drop of water, excessive heat, etc. Another link, maybe clearer than the other. Other than that somehow the data vanished from the memory cards mentioned above, do you have any proof that it was from magnets, and if so how were they exposed to such high magnetic forces? Just curious, mostly because my first gut feeling, before I started actually looking for an answer, was that magnetic exposure would be highly undesirable.

Fred
One of the two people did it as a test, had images on the card put a strong magnet on it, i am not sure how long, then went to read it and could not read the card. The magnet he used was the type magicians use.
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Old 07-15-2008, 12:05 PM   #11
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If the magnet was heavy it may have damaged the card that way or the static discharge from wearing sock in winter and walking over and picking up the card may have zapped it.
That I find more plausible than magnets.

http://www.webopedia.com/DidYouKnow/...002/static.asp

Microchip damage can occur if it is exposed to static electricity as low as 10 volts, and humans are not able to perceive static electricity until it has reached about 1,500 volts. (Walking across a rug can produce a static electricity voltage of up to 12,000 volts, but static voltage is not life threatening.) So it is possible to damage a hard drive with static electricity that is not even felt by the person because it is at such a low voltage. Also, computers become increasingly susceptible to static electricity damage as more and more circuitry is built into them.
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Old 07-15-2008, 12:12 PM   #12
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Like all the pp's have said, most electoninc media like CF cards are not affected by stong stationary or mildly fluctuating magnetic fileds ( like those used in scanners etc). However even a weak magnet can affect tape media and moderate stationary fields can mess up HDD..

However it should be noted that even a moderate rapidly fluctuaing magnetic field sourse like MRI's/medical scanners and other equipment that use magnetic resonance ( zero field to high strenght field) can mess up anything electronic....even flash based cards
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Old 07-15-2008, 12:13 PM   #13
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Originally Posted by The Grays View Post
One of the two people did it as a test, had images on the card put a strong magnet on it, i am not sure how long, then went to read it and could not read the card. The magnet he used was the type magicians use.
I did the test myself (see above) and saw no change on the card at all. In addition, I left the card on the magnet overnight and checked it again in the morning and it is still good. Maybe the magician's magnet was magic, but my experience says that it's not a concern.
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Old 07-15-2008, 12:41 PM   #14
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...and humans are not able to perceive static electricity until it has reached about 1,500 volts....
Try sticking your tongue between the contacts of a 9 volt battery and then tell me that you can't perceive electricity below 1,500 volts. Or play with your electical outlet (don't really!) which is probably just 120 or 240 volts. What makes static electricity special (it's not really different than electricity from a battery or electrical outlet) is that it has very low amperage.

If you think of electricity as being like water - volts is the speed of the water and amps is the amount of the moving water. Static electricity shocks are like a water pic - very fast moving but not a lot of water. Your power outlet is like a strong, swift river - much slower than the water pic but it'll overpower you.
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Old 07-15-2008, 12:47 PM   #15
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Originally Posted by MarkBarbieri View Post
Try sticking your tongue between the contacts of a 9 volt battery and then tell me that you can't perceive electricity below 1,500 volts. Or play with your electical outlet (don't really!) which is probably just 120 or 240 volts. What makes static electricity special (it's not really different than electricity from a battery or electrical outlet) is that it has very low amperage. .
LOL You are too much!

If you notice in the article they did specify static electricity when they said 1,500 volts.
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