The magnetic card is made of high-strength and high-temperature resistant plastic or paper-coated plastic, which is moisture-proof, wear-resistant, flexible, convenient to carry and stable and reliable to use. Usually, one side of the magnetic card is printed with explanatory information, such as the direction of card insertion; A magnetic layer or stripe with 2-3 tracks on the other side to record relevant information and data.

In essence, it is the same as the tape or disk used in the computer, and can be used to record letters, characters and numerical information. It is firmly combined with plastic or paper by bonding or heat sealing to form a magnetic card. A magnetic stripe usually contains more information than a long bar code.

The recording principle of extended data magnetic card

The recording head consists of an annular iron core with a gap inside and a coil wound on the iron core. Magnetic cards are made of a substrate made of a certain material and granular magnetic materials evenly coated on the substrate. When recording, the magnetic surface of the magnetic card moves at a certain speed, or the recording head moves at a certain speed and contacts with the gap or magnetic surface of the recording head respectively.

Once the current is applied to the coil of the magnetic head, a magnetic field proportional to the current will be generated at the gap, so the magnetic body in the contact part between the magnetic card and the gap will be magnetized.

If the recording signal current changes with time, when the magnetic body on the magnetic card passes through the gap (because the magnetic card or the magnetic head is moving), it will be magnetized to different degrees with the change of current. After the magnetic card is magnetized, the magnetic layer of the magnetic card leaving the gap will leave residual magnetism corresponding to the current change.

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