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[Discussion] [How It Works #17] Wireless Charger, all about this technology!

2019-09-13 03:30:41
2056 63

Hello Dear MIUI Fan's!
Today you'll know more about Wireless charger technology. Basic principles of work and technical solutions that make it possible to implement this technology.

What are we talking about!
There are several technologies for transmitting electricity through the air, including using a laser, a sound wave, and other interesting methods. But so far only one of them can be called commercial - the use of electromagnetic induction, through which Faraday and Tesla tried to transfer energy. The most common inductive charging standard to date has been developed by Wireless Power Consortium for about twelve years. This standard is called the Chinese word Qi - pronounced as "chee" in English or as "qi" in the Russian translation tradition. Almost all mobile phone manufacturers officially support it, starting with Samsung, Sony, Lumia phones, ending with small companies whose names do not tell anyone anything. Charging stations that meet this standard are already equipped with some American airports, the British McDonald's and Starbucks, and this, as it becomes clear, is only the beginning of the list. It can also include new Ikeevsky furniture and lamps with built-in charging panels - they began to be sold for a long time in Europe, Asia and America. Even Apple, which, as always, is a bit aloof and does not officially support Qi, seems to adhere to the principles of WPC in its watches and smartphones.

How it works?

Wireless charging using WPC technology implies the presence of induction coils in the phone and charger: one acts as a receiver, the other as an electricity transmitter. When the charge is connected to the mains, voltage arises in it, and a magnetic field around its transmitter-coil. When the telephone enters this field, the electromagnetic waves in its receiver coil are converted to electricity - the phone’s battery starts charging. The Qi standard implies that for complete energy transfer, the distance between the devices should not exceed 3-5 centimeters. That is, they should practically touch each other. Therefore, most of the current induction charges are small panels on which you need to put the phone. Moreover, their efficiency is about 75–80% - slightly less than that of wire charges.

The basis for the creation of devices was electromagnetic induction, therefore, charges of this type are often called "inductive" or "magnetic". The principle of its action is the ability of electromagnetic radiation to transmit current at a short distance without wires. This requires two coils, one of which will be a conductor, and the second to act as a receiver. If you place them close to each other and put on the first alternating current type, an alternating current will also form on the second receiver. It can be used as an energy source for the phone after transformation into a constant voltage of the required value.

The premier standard for wireless chargers
Qi is the premier standard for wireless power transmission. It is actively used by all manufacturers of mobile phones and chargers. At the moment, there are three main indicators of charge power:

For comparison, such power is provided by wire charging:
1. Standard Charging Unit for iPhone - 5W
2. Charging unit for iPad - 10W
3. Quick Charge 3 - 18W

Wireless chargers have lower efficiency due to the transfer of energy through the air. Tests show that the phone accepts only 4.2W from 5W (efficiency 85%), while 10W - 9.1W (efficiency about 90%).

In the photographs is a current and voltage meter that the phone receives from wireless charging. This device shows how much the phone takes charge from wireless charging.

What are the pros and cons!?
If we talk about the average user, inductive charging has only one significant advantage. It eliminates the need to connect the cable to the phone (player, camera, watch, and other small devices). And although it is called wireless, it does not exempt from the wire itself, since it is needed to connect the charging panel to a wall outlet. These panels have other drawbacks: they are a bit more expensive and on average they charge one and a half to two times slower.

Is wireless charging dangerous !?
This is probably the most popular question asked by the Wireless Power Consortium, and mobile manufacturers, of course, answer that it is safe. Manufacturers of electric shavers and toothbrushes are trying to convince everyone of this - the same induction principle has long been applied to recharge them. But it should be borne in mind that the electromagnetic waves, due to which wireless panels transmit energy, belong to the spectrum of the so-called non-ionizing (and therefore safe, in contrast to, say, x-ray) radiation. Electromagnetic waves of the same spectrum serve to transmit the signal of radio stations, cell towers, Wi-Fi routers. For example, the signal of a mobile phone is transmitted continuously and to far greater distances, but its receiver can operate with a small amount of power (within 1–2 watts). The maximum power of Qi wireless panels is significantly higher - 5 watts and more. But they (so far) operate at extremely short distances, in addition, they automatically turn off (which means they stop emitting waves) if the device is charged.

In any case, no one has yet presented convincing evidence that Qi wireless charging (like a cellular signal) can be a health hazard. However, the Wireless Power Consortium also works on more powerful wireless chargers (up to 120 watts) that can charge laptops. But they are still being careful with these devices, and no one seems to be releasing them.
Wireless Charging Examples
Samsung Wireless Charging Pad

The latest invention of Samsung, which is praised for the ability to charge the phone, regardless of its position on the charging panel. The Charger supports not only the WPC standard, but also the technologies of competing and lesser-known organizations AW4P and PMA. This means that, most likely, it will not matter for him which phone you have. If there is a wireless recharging module, everything should work. Also, in the video of the manufacturer, they promise that this Wireless Charging Pad can charge the Galaxy battery by 60% while you sing a song (but this, you must think, is just an advertisement).


Best seller and, judging by the reviews, the best wireless panel on Amazon. Compatible with Qi receivers. A micro-USB cable is attached to it (which means it can be connected to a laptop or portable battery). Pretty reliable and inexpensive model.


Perhaps the most exciting promise of recent years is a breadbox-sized transmitter that allows you to charge phones, smart watches and bracelets, remotes or gamepads up to 10 meters away. This is more of a wireless technology, freeing up fuss with a charger. It does not matter whether the phone is on the table or in your pocket: as soon as it is discharged and is within the range of the transmitter, it will begin to charge it. However, the charging device must be equipped with a special Cota receiver.

iQi Wireless Charging Receiver

Today on the market there are more than 500 models of devices with support for wireless charging.

Recent Apple models have this feature. Samsung and Nokia also integrated it a few years ago. The companies included in the Wireless Power Consortium also support wireless charging technology. The following list of models into which WPC or Qi technology is integrated is not exhaustive, but it gives some idea of ​​the market:

Apple Wireless Charger supports
iPhone 5 / 5C / 5S, iPhone 6/6 Plus / 6S / 6S Plus, iPhone 7/7 Plus, iPhone 8/8 Plus, iPhone X, iPhone Xs, iPhone 11 and other

Samsung Wireless Charger:
Galaxy A7, Galaxy A9, Galaxy J7, Galaxy A310, Galaxy S6 / S6 Edge / S6 Edge Plus, Galaxy S7 / Edge S7 / S7 Edge Plus, Galaxy S8 / S8 Plus, Galaxy S9 / S9 Plus, Galaxy S10 and other

Huawei Wireless Charger:
P8, P8 Lite, Mate 8, P9, P9 Lite

LG Wireless Charger:
G3, G4, G5, Stylus G4, K10

Sony Wireless Charger:
Xperia Z5, Premium Z5, Compact Z5, Xperia X, Xperia XA

Nokia Wireless Charger:
Lumia 950, Lumia 650

HTC Wireless Charger:
One X9

Motorola Wireless Charger:
Moto X, Moto G

Xiaomi Wireless Charger Source

Xiaomi recently introduced the world's first 20W wireless charging station. The new Mi 9 is fully charged from the Mi Wireless Charging Pad in just an hour and a half - and this is already at the level of wired devices.
Xiaomi Debuts World’s First 30W Wireless Charging Technology, Reveal Key Info About Mi 9 Pro 5G!
By the way, you can check whether your smartphone supports Qi technology by checking on the Consortium website. If you have a different model, do not panic. In this case, you just need to buy a special receiver in addition to the charger, which should be placed next to the batteries of your gadget.

The disadvantages of wireless charging
If wired chargers simply disappear between charging cycles, then when using contactless charging, the user encounters other disadvantages.
Depending on the size of the charging surface, you can charge two or more devices at the same time, but such chargers are more expensive.
Charging can be done remotely, but you still need to be close to charging - do not take the device further than 4cm.
Nonetheless, remote charging takes more time than the contact method, since electricity is “lost”. Therefore, it is better to hold the phone only on the charger plate.
Thanks to Administrator and SMod and Mod!

Related thread:
[How it Works #1] Proximity and Light Sensors!
[How it Works #2] Know More About Fingerprint Sensor!
[How it Works #3] What happens inside your smartphone during a phone call?!
[How it Works #4] Type of Touchscreen and How it Work!
[How it Works #5] Type of Display and How it Work!
[How it Works #6] Camera in smartphone, and how it works!
[How it Works #7] What is the battery in your phone or smartphone?
[How it Works #8] What is a processor in a mobile phone?
[How it Works #9] What is a RAM in smartphone!
[How it Works #10] How to produce processors, and what are the difficulties in their manufacture!
[How it Works #11] What is a Modem in a Mobile Phone?
[How it Works #12] What is Fast Charging in a Smartphone!
[How it Works #13] Why You Should Not Include These Features in MIUI!
[How it Works #14] What is GPU in Mobile Phone!
[How it Works #15] What is Bluetooth and how it works!
[How it Works #16] What is NFC and how does it work?


Number of participants 3 Experience +50 Pack Reason

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2019-09-13 03:30:41
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Pro Bunny

jihad.ptk1 | from Redmi Note 7 Pro


nice information
2019-09-13 03:46:23
Thank you for sharing this with us.
2019-09-13 04:03:11

Resource Team

iMKajal | from MI 8


Informative Thread!
2019-09-13 04:21:22

Wizard Bunny

Bart.ek1 | from app


Thanks for sharing this interesting article.
2019-09-13 04:30:07

Advanced Bunny

JustCow | from MI 8 Lite


2019-09-13 04:51:10

Grand Master Bunny

Seragios | from Redmi 5


Thanks for sharing
2019-09-13 06:12:15

Advanced Bunny

Mahmoud m. Hafez | from MI 8 Lite


thanks for sharing
2019-09-13 06:24:58

Grand Master Bunny

$huvo | from Redmi 4


2019-09-13 08:10:23
Interesting article.
2019-09-13 10:42:58

Master Bunny

tonibagan | from Redmi 7A


where is oppo vivo lenovo?
2019-09-13 21:28:09
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