Can a cellular phone demagnetize a credit card?

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In summary: RegardsIn summary, the conversation discusses whether a cellular phone can demagnetize a credit card and why loudspeakers make strange noises when the phone rings. It is suggested that the speakers in cell phones are small and well-shielded, making it unlikely for them to demagnetize credit cards. The conversation also delves into the electromagnetic waves emitted by cell phones and how they work, with a mention of the mythbusters testing this topic with ele skin wallets. The conversation concludes with a discussion on the strength of the cell phone's magnetic field and how it may or may not be strong enough to demagnetize credit cards.
  • #1
Feynmanfan
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Hi there!

Can a cellular phone demagnetize a credit card? Why do loudspeakers make a strange noise when the cellular phone rings?

I don't know the physical explanation to all this. I'd be grateful if you could tell me what kind of electromagnetic wave phones radiate and how they works.

Thanks
 
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  • #2
1) A speaker can demagnetize a credit card. Since cell phones have speakers, it's conceivable that this can happen. On the other hand, the speakers are quite small, and probably shielded pretty well, so I'd bet it rarely happens.

2) When your cell phone is about to ring, the tower sends out a message checking to see if your phone is available. Your phone responds with a message saying it is available, at its highest transmission power. This occurs a half second or so before your phone actually begins to ring. Your phone rarely transmits at its highest transmission power, but does so during this phase of the call to make sure the tower hears it.

- Warren
 
  • #3
Didn't the myth busters do something like this? Oh wait that was with ele skin walets.
 
  • #4
Thank you, Warren
 
  • #5
It takes a pretty large H field to reorient the magnetic dipoles on the strip.
My degausser uses at least 50 watts to do the job in a 6" torus field at 60 Hz.
Maybe if you held them tight together ... ( H is 1/r )
I can't quantify it but what is the cell putting out ... a watt or two ?
And might not this be above a cutoff frequency for reorientation ?

Best
 

1. Can a cellular phone really demagnetize a credit card?

Yes, it is possible for a cellular phone to demagnetize a credit card. This is because most credit cards use magnetic stripes to store information, and the magnetic field produced by a cell phone can interfere with this data and cause it to become corrupted.

2. How close does a cellular phone need to be to a credit card to demagnetize it?

The exact distance needed for a cellular phone to demagnetize a credit card may vary, but in general, the phone would need to be within a few inches of the card. The strength of the phone's magnetic field and the sensitivity of the credit card's magnetic stripe can also affect this distance.

3. Can a credit card be demagnetized by a cell phone even if they are not in direct contact?

Yes, a credit card can still be demagnetized if it is in close proximity to a cell phone, even if they are not in direct contact. This is because the magnetic field produced by the phone can still affect the data on the magnetic stripe of the card.

4. Are some types of credit cards more susceptible to demagnetization by a cell phone?

Yes, some types of credit cards may be more vulnerable to demagnetization by a cell phone. For example, older cards with weaker magnetic stripes may be more easily affected than newer cards with stronger magnetic stripes. Additionally, cards with multiple layers of protection, such as chip-enabled cards, may be less likely to be demagnetized.

5. How can I protect my credit card from being demagnetized by a cell phone?

To prevent your credit card from being demagnetized by a cell phone, it is recommended to keep your card away from your phone. You can also use a protective sleeve or wallet that blocks magnetic fields. Additionally, it is important to avoid exposing your credit card to other sources of strong magnetic fields, such as magnets or electronic devices like laptops.

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