What is the principle of mobile phone wireless charging?

There seems to be a kind of magic in wireless charging of mobile phones, which allows us to get rid of the shackles of charging cables. But it can't charge the phone like WiFi signal as long as it is within a certain range.

In fact, wireless charging does not let us get rid of the shackles of wires, but this tangible wire is replaced by an invisible wire that still restrains us. When charging, the mobile phone must be placed on a charging board, and it must be placed on the designated area of the charging board to be able to charge, and the effect of charging at a slightly offset position is not good.

Wireless charging is not a tasteless thing, at least when you need to use the mobile phone, you can use it, instead of picking up the charging cable or pulling the charging cable around. The charging cable is repeatedly used and repeatedly bent and cannot escape the end of the broken skin and exposed core.

The scene of using wireless charging is never from the lowest battery to full, but "keep the battery full at any time". For many people who don't use their mobile phones frequently at work, but occasionally pick them up to read text messages or make calls, wireless charging can not only avoid the trouble of charging, but also protect the fragile charging socket of the mobile phone.

Of course, wireless charging is also suitable for home scenes. When charging, you don’t need to find the charging cable all over the world. You only need to put the phone on the charging board before going to bed. When you wake up the next day, you can just pick up the phone and use it without worry. Pull to the line.

In order to cater to our demand for charging and playing with mobile phones, wireless chargers with upright design have appeared on the market, so that you can watch movies, chat, etc. while charging.

Some charging boards are also designed to be hidden, directly embedded on the table, the table top is clean and tidy, there is no messy line, and it is full of technology.

For engineering men, wireless charging is a transformer

Inside the wireless charging board, there is a coil with a diameter of about 1 inch and a half wound around 10-20 turns, and there is a similar pairing coil on the back of the phone. The coil in the charging board is driven by about 1 ampere of alternating current, and the frequency is about 200KHz. 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 a current through the change of the induced magnetic field.