Mobile wireless charging seems to have a kind of magic, can let us get rid of the shackles of the charging line. But it can't charge a cell phone like WiFi, as long as it's within a certain range.
In fact, wireless charging does not let us get rid of the shackles of the line, but the tangible line replaced by the invisible line is still binding us. When charging, the mobile phone must be placed on a charging board, and it can be charged only when it is placed in the designated area of the charging board. The charging effect is not good if it is slightly offset.
Wireless charging is not a chicken thing, at least when you need to use a mobile phone, you can use it without taking off the charging wire or pulling it around. The repeated use and bending of the charging cable can't escape the result of exposing the core.
The scene of using wireless charging is never from the lowest charge to full charge, but "keep the charge full at all times". For many people who don't often use mobile phones at work, but still occasionally pick up to read text messages or answer phone calls, wireless charging can not only avoid the trouble of charging, but also protect the fragile charging socket of mobile phones.
Of course, wireless charging is also suitable for home scenes. When charging, you don't need to search all over the world for where the charging line is. You just need to put the mobile phone on the charging board before going to bed. When you wake up the next day with dim eyes, you can directly pick up the mobile phone and use it without worrying about pulling the line.
In order to meet our demand of playing with mobile phones while charging, wireless chargers with vertical design appear in the market, which can realize watching movies, chatting and so on while charging.
Some charging boards are also designed to be hidden, directly embedded into the table, the table clean and tidy, no messy lines, but also full of science and technology.
For engineering men, wireless charging is a transformer
Inside the wireless charging board, there is a coil about an inch and a half in diameter, wound 10 to 20 times, and there is a similar matching coil on the back of the mobile phone. The coil in the charging board is driven by about 1 ampere of alternating current, and the frequency is about 200 kHz. The alternating current in the charging board generates a constantly changing magnetic field in the coil, which in turn induces the coil in the mobile phone to generate current through the change of the induced magnetic field.
As early as 1899, Tesla began to explore wireless power transmission. He built a radio power transmission tower in New York, and conceived a magic wireless power transmission method: Taking the earth as the inner conductor and the earth ionosphere as the outer conductor, by amplifying the transmitter in the radial electromagnetic wave oscillation mode, a low-frequency resonance of about 8Hz was established between the earth and the ionosphere, and then the ring was used Electromagnetic waves around the earth's surface transmit energy.
Now, we are constantly researching and experimenting on the basis of Tesla, and have developed wireless charging technology. At first, Tesla's idea is gradually landing in the display.
Why should mobile phone wireless charging be close to the charging board? Why can't it be as far away as WiFi?
At present, the main ways of wireless charging are electromagnetic induction (mm), magnetic resonance (CM), electric field coupling (mm) and radio wave receiving (m). Among them, the technology of electromagnetic induction is more mature and the charging efficiency is higher (up to 80%). In addition, its circuit structure will be relatively simple, so electromagnetic induction wireless charging will be used on mobile phones.
In 2007, a research team from Massachusetts Institute of technology successfully used magnetic resonance to light a 60 watt bulb about 2 meters away from the power supply, and the power transmission efficiency reached 40%. The principle of electromagnetic resonance wireless charging technology is the same as that of sound resonance. The energy is exchanged through resonance, and the charging distance extends to 3-4 meters.
Wireless charging technology is developing gradually
Wireless charging is realized on small mobile phones, cameras and other portable devices. As a breakthrough, wireless charging technology will bring us broader application scenarios in the future. In the future, maybe cars, computers, mobile phones and other devices that need electricity do not need to lay so many lines, nor do they need so large batteries.