Статьи AccessoriesArticles

# Wireless charging for your phone: utopia or reality?

While in Europe cafes and restaurants are equipped with platforms for wireless charging smartphones, such technology continues to seem “out of the ordinary” to the Russians. To fill the gaps in the knowledge of domestic users, we will talk about the pros and cons of wireless memory.

Wireless transmission of energy until recently seemed like a crazy fantasy, but today it is quite feasible. Wireless storage devices that are rapidly replacing traditional wired chargers in the Western market are likely to soon win the windows and hearts of consumers in Russia. It’s still difficult to find wireless chargers in domestic communication stores, but gadget users are actively interested in how these unique devices work and whether they cause harm to human health. We will try to answer the most common questions in this article.

Content

## How does a wireless charger for mobile phones work?

To understand the principle of wireless charging, we will have to recall the school physics course and, in particular, the meaning of the term “ electromagnetic induction ”. Induction is the formation of current that occurs due to a change in magnetic flux in a closed loop.

The wireless charger contains a transmitting electromagnetic coil ( Transmit Coil ) - one that generates a magnetic field. Inside the gadget should be a receiving coil ( Receive Coil ) - which is why not every smartphone can be recharged wirelessly. The greater the distance at which the two coils are from each other, the weaker the flow of energy. It is important to keep in mind that two coils should not be in contact with each other.

The wireless power standard is called Qi .

The wireless charging method has long been relevant for toothbrushes and electric razors. Alas, all this time the technology was accompanied by customer complaints that charging is too slow and unstable.

To recharge a smartphone, just put it on a special stand - after that the transmitting coil is activated and will begin to "share" the current. You can charge in this way anywhere - at home, in the car, in a public place. In some countries, wireless charging stands are housed in a cafe so that the visitor can usefully spend time waiting for an order.

## How effective is wireless charging?

A wireless charger is still less efficient than wired charging - no one is going to dispute this claim. Confirming it is quite easy - with the help of simple calculations.

Charging efficiency mainly depends on 2 indicators: current strength (measured in amperes) and voltage (measured in volts). Traditional charging on average delivers 1 Ampere of current at a voltage of 5 V - as a result, a 3000 mAh battery charges from scratch "to the brim" in about 3 and a half hours . Wireless charging at the same voltage delivers only 0.65 Amps (again on average) - this means that it takes at least 4 hours to fill up the battery with energy.

All the above calculations, of course, are approximate. The effectiveness of wireless charging depends on other factors - for example, on:

• Coil sizes.
• Distances between coils. In order for the charging to proceed stably, the distance between the gadget and the stand should not exceed 5 cm.
• Winding resistance.
• The presence of the so-called skin effect - an effect in which current flows only through a thin surface layer of the conductor.

## Advantages and disadvantages of wireless charging

Despite the fact that the efficiency of wireless chargers leaves much to be desired, these devices have a lot of advantages:

• Lack of wires . The most obvious plus: you no longer have to insert the cable into the gadget. In fact, this advantage is "far-fetched", because the user will not be able to do without wires completely - you need to somehow energize the station itself.
• Universality . Using one wireless memory, you can charge any mobile device that supports this feature.
• Low prices . In domestic electronics stores, you can’t find a wireless memory cheaper than 1 thousand rubles, but, for example, you can buy such a device on AliExpress for only 200-250 rubles.

The main disadvantages of wireless storage devices have already been mentioned - this is low efficiency and the need to keep the coils in close proximity to each other. Among other, less significant minuses, you can include the following:

• In the process of wireless charging, the mobile device heats up very much - the consequence of this sometimes becomes the battery failure.
• The “mobile phone”, which is charging, receives radio signals with significant distortion.
• Some of the gadget models (for example, iPhone) can be recharged wirelessly only through a special case or adapter for wireless charging. The acquisition of such equipment, of course, promises additional costs.

## Is it safe to use wireless charging?

Some users of mobile devices refuse from wireless charging, because they are worried, as if magnetic radiation were not harmful. Health concerns are nothing more than paranoia : not only experts say this, but also members of the Wireless Electromagnetic Energy Consortium ( WPC ), the organization that developed Qi technology.

The power of the wireless memory is only 5 watts - this is definitely not enough to affect the human body. Negative consequences can only be when using a charger with a power of 120 watts - such devices are also produced, but not on an industrial scale, and they are designed to recharge laptops.

The electromagnetic signal of the wireless memory in terms of impact on the body is similar to a cellular signal - with the only difference being weaker and it stops when the smartphone is charged.

Users are worried not only about health, but also about the safety of personal data. In mid-2016, it became known about a new method of hacker attack. Thanks to fake USB wires, hackers can steal data (passwords and pin codes) from victims' phones while they recharge gadgets from computer ports - this was told by the Aries Security agency. Due to such news, users have become even more cautious about chargers placed in public places - including wireless ones .

It is not possible to steal data through wireless charging.

Theft of information via a USB cable has become possible, because the wire has 2 functions - it provides recharging of a mobile device and the exchange of data between gadgets (smartphone and PC). Wireless charging is not capable of performing the second function . It will be possible to begin to worry when developers endow wireless stations with the functions of a data exchange point, but this is not expected in the near future.

## Best Wireless Phone Chargers

The user who is interested in the prospect of wireless charging the gadget should pay attention to the following memory models.

### Samsung PG920

Despite the fact that the wireless charging market is still young, Samsung's charger has already become its classic. The key advantages of the PG920 are its compact size, attractive appearance and rather low price (about 1000 rubles).

Please note that charging from Samsung is universal, and therefore can recharge gadgets not only of the Korean "giant", but also of other manufacturers.

### Tylt vu

The main feature of Tylt Vu charging is its unique shape. Charging is a broken plane, consisting of 3 surfaces. Thanks to this form of memory, it is convenient to use the gadget while it is storing energy.

### Woodpuck fast edition

Users can be scared off by a price of \$ 40, but there is something to pay for. Woodpuck is not only the most stylish and original wireless charger, but also the most effective.

Woodpuck is made of real bamboo, and therefore is considered the most "environmentally friendly" memory. The device works with all gadgets equipped with the Qi function, and charges them much faster than analogs - studies have shown that the user can save up to 40% of the time.

### Nokia DT-903

The DT-903 is another charger with an unmatched design. During recharging the gadget, the platform burns quite brightly, so that the user can do without a nightlight. If the glow interferes, it is easy to turn it off by pressing the button located on the bottom plate.

The efficiency of the DT-903 is at a fairly high level: according to assurances of Nokia engineers, the wireless charger charges the smartphone in the same time as wired charging. The device from the Finnish company is compatible not only with Lumia devices, but also with gadgets from other manufacturers. The cost of this curious device is about 2500 rubles.

## Conclusion

Wireless chargers impress with not only a combination of efficiency and effectiveness, but also simplicity. Everything ingenious is simple : it is enough to use two inductors to stop being a slave of wires - Faraday could have reached the creation of a wireless memory even a century and a half ago, if he knew in what era his descendants would have to live.

The primitiveness of the design is able to push the owner of the gadget to independent experiments with electromagnetic radiation and conductors - on the Internet, alas, there are a lot of articles advising how to assemble wireless charging with your own hands, for the authorship of room inventors. We recommend that you start such attempts only if you have a physical faculty diploma in your desk drawer. An amateur during such experiments can easily disable the gadget.