Test materials: IC card for public transportation, bank card with magnetic stripe, smart electric card with chip, HID card with rice card, and two magnets
The phone simply can not eliminate the magnetic
First, put a public transportation IC card on the desktop, press the card with the mobile phone, and then use the landline to dial the mobile phone. The call duration is 1 minute and 01 second. Then, this IC card was taken to the corresponding machine for operation, and it was found that the IC card did not fail.
The above “degaussing” tests were repeated with bank cards, smart cards, and HID cards, respectively, and the time of each mobile phone call was controlled at more than one minute. However, after "degaussing" the above three types of cards using a mobile phone, it was found that the three cards can be used normally on their respective machines without demagnetization.
Test conclusion: It is not correct to say that it is easy to degauss the cards placed together when the mobile phone calls for a long time.
Two magnets eliminate bank cards
First of all, with a magnet, facing the bus IC card, bank card, smart electric card, HID card brushing 50 times, the results did not degauss these cards.
Then a magnet was added to perform the same test on both sides of the above four types of cards with two magnets. As a result, bus IC cards, smart cards, and HID cards have not been degaussed. However, putting the bank card after processing into the ATM machine was unexpected!
I saw the green light on the ATM telling machine flashing constantly, and then issued an alarm sound. A huge exclamation mark is displayed on the screen: "The card is invalid, please retrieve the card." After 2 seconds from the exclamation point, the bank card is automatically ejected by the machine.
Attempted to insert this bank card into ATM cash machine several times, but the cards were spit out by the machine. After replacing an ATM, the card was still ejected. This shows that the bank card has been "demagnetized" under the effect of two magnets.
Test conclusion: Strong magnets can indeed degauss bank cards with magnetic stripes, but they have no effect on the other three types of cards.
Bank magnetic card is afraid of strong magnetic field
Of the 4 cards, only bank cards were degaussed by magnets, said Yang Yong, an associate professor at the Huazhong University of Science and Technology's School of Electrical Engineering. This is because these four cards have different carriers for storing information. At present, most bank cards are magnetic cards. The magnetic strip on the card is coated with liquid magnetic material on the card, or it is attached to the card with a thin solid magnetic strip. If the magnetic card is disturbed by a strong external magnetic field, the information in the magnetic stripe will be destroyed, which will cause the card to become unusable. Therefore, magnetic cards should not be too close to strong magnets or objects that emit strong electromagnetic waves. However, in general, the magnetic field generated by a cell phone is not enough to degauss the magnetic card.
Contact IC card is afraid of static electricity
Smart card This card with a metal surface is a contact IC card. This card discards the original magnetic stripe store and uses integrated circuits to store information. For example, a mobile phone card belongs to such a contactless IC card. However, Professor Yang pointed out that this type of card uses a few contacts to connect the card reader and the internal circuit of the card to complete the information exchange. The card reading and writing data is the direct use of electricity, not the magnetic head.
Therefore, this kind of card basically has no problem of "demagnetization." However, contact type IC cards also have weaknesses, that is, they are afraid of abrasion and static electricity. "In the winter, static electricity may be generated on clothing, and sometimes the voltage is as high as several thousand volts. This may damage the part of the card where information is stored. Therefore, when using this type of card, it is necessary to pay attention to anti-static electricity."
Non-contact IC card fear
Public transport IC cards belong to non-contact IC cards, and cards of the same type also include thick HID cards, ID cards, etc. Its essential structure is not much different from that of a contact type IC card, but it is only changing the original metal contact setting to wireless transmission and reception. Its working principle is that the card reader emits an electromagnetic wave that changes according to information, and an inductive coil inside the IC card converts the electromagnetic wave into an induced current for transmitting information and driving the chip.