Using easycard has become a daily habit of modern people in Taiwan Province, China. Whether you take the MRT, the bus, or go to a supermarket or a cooperative store to spend money, you can debit the card by simply "beep" the card near the sensor, which is convenient and fast. However, easycard has neither batteries nor a card reader. Why can it transmit data? Easycard can take the bus, MRT and go to the store for consumption as long as it is close to the sensor, which is very convenient and fast. Using easycard has become the daily life of people in Taiwan Province, China. How did easycard Company easycard do it?

in 1831, Michael Faraday, a British scientist, discovered that when a magnet passes through the middle of an uncharged coil or the coil passes through a stationary magnet, the coil will generate an induced current due to the change of the magnetic field, and the more turns the coil has or the faster it moves, the stronger the generated current will be. This magical phenomenon of "magnetic electrification" is called electromagic induction, which is one of the principles used by easycard. Faraday found that when the magnet passes through the coil or the coil passes through the stationary magnet, the coil will have induced current due to the change of magnetic field. Wikimedia mon

The contactless induction technology used in easycard is called RFID (Radio Frequency Identification). Every easycard has an RFID Tag. Although the tag itself will not discharge, when it is near the magnetic field of a Reader, it will make the coil on the tag generate current through the principle of electromagnetic induction, which is enough for the tag to transmit information to the reader.

not only in easycard, but also in inductive credit cards, electronic toll collection (etc) on expressways, anti-theft devices in libraries or shops, dormitory access cards and pet chips.

NFC (Near Field Communication) is an extended version of RFID, which also operates by electromagnetic induction. The difference is that RFID provides information in one direction, while NFC enables two devices in a short distance to exchange information in two directions, which is fast and safe. With NFC, mobile phones can carry out mobile payment that we are familiar with 3-6. Electromagnetic induction can also be used in this way

The induction cooker at home also uses the principle of electromagnetic induction. The coils inside the induction cooker will constantly alternate magnetic fields, indirectly making the metal cooker generate Eddy Current, so as to achieve the effect of heat generation by current, and the food in the pot can be heated 7,8. In addition, electromagnetic induction can also be used to transmit audio!

think about it. When you go to the cinema to enjoy a movie today, does the interference of the audience discussing the plot or talking on the phone make your rational line break? For hearing-impaired people, although their hearing AIDS can appropriately amplify external sounds and make sound messages "clear", when external sound messages come from electronic devices (such as bees, speakers and broadcasting systems), the hearing aid microphone will reprocess these "mechanical sounds processed by electronic devices" before playing them, which leads to the sound being easily "distorted" in several conversion processes, and the quality of natural sound effects is easily discounted, not to mention.

at this time, the use of T-coil can help the hearing-impaired to hear more clearly! Most hearing AIDS have T-coils, which are formed by winding wires around a ferrite rod. As long as hearing-impaired people turn on the "T-function" in an environment with a hearing loop/induction loop system, the metal coil will generate alternating current, which will directly adjust and amplify the target sound source signal after receiving it, thus avoiding several sound treatments and allowing users to hear clear and pure sound 9,1. T-coil is a metal coil device wound on a ferrite rod, which is built in most hearing AIDS. What is the difference between the Hearing Loop coil and Bluetooth and remote microphone system?

There is not only one technology that can transmit audio wirelessly. Besides T-coil, hearing AIDS often have Bluetooth function or can be matched with Remote Microphone system. What's the difference between these three technologies?

Although the Bluetooth function is convenient for listening to music and answering telephone calls, it is limited by the distance and the model of specific hearing AIDS. Although the remote microphone system can be connected with the exclusive microphone worn by the speaker, it is still easy to limit the number of equipment connections and the pairing of assistive devices.

T-coil is different. Most hearing AIDS have such devices, and the setting of induction coil can also be changed according to the needs of the venue. The range can be as large as a sports field, or it can only surround the listener (for example, it can be set on the floor or chair), and 9 can be used as long as it is installed.

compared with other personalized wireless devices, the T-coil saves the step of pairing one by one, and it is not limited by the distance as long as it moves in the installed place, and it can also be used by many people within the sensing range. Therefore, this technology is mostly used in public places, such as foreign stations, churches, schools, museums or opera houses, etc. 11,12, so that hearing-impaired people can easily enjoy performances, tours or speeches without noise or noise. The sign of T-coil reminds people with hearing loss that they can turn on the T-function to listen. Hearingloop builds a barrier-free society with electromagnetic induction

At present, Taiwan Province, China has provided induction coil service in the service desk of the National Hall, the classroom and lecture hall of the National Library, and the Yilan Performing Arts Hall. Especially in stations, airports, shops and other places where the echo is heavy and noisy, we usually have to listen carefully to the broadcast information of flights/trains to vaguely distinguish them, not to mention that such troubles will multiply for the hearing-impaired people; If T function can be used at this time, I believe they can listen to the broadcast more easily. The T-coil service of the British subway makes it easy for hearing-impaired people to hear broadcast messages and reduce their anxiety caused by the noisy environment. AV Magazine

From easycard, mobile payment, induction cooker and hearing barrier-free facilities that are used every day, there may be more electromagnetic induction applications in life than you think. These discoveries and inventions have improved our quality of life and made life more convenient. You can also take a closer look on the way to work today. What other products or services use electromagnetic induction?