In recent years, wireless charging of smartphones has found more and more fans. Already on the market over 500 models various devices that support this method. You may have been using it for years if you have an electric toothbrush: just put it on the docking station and it will start charging.
The principle of charging your smartphone or smart watch is the same. Very practical, no need to connect the cable. But what is wireless charging and how does it work?
The secret is in electromagnetic induction
How can energy be transferred from one object to another? Wireless charging works on the principle electromagnetic induction. This phenomenon was first described in 1831 Michael Faraday, who discovered that if a source of magnetic field is moved through a coil, an electric current will appear in it. Michael Faraday found the relationship between electricity and magnetism.
How does it work electromagnetic inductioncan be easily explained by performing the following experiment:
- Take magnet from the refrigerator.
- Connect a light bulb to a simple copper coil.
- move the magnet back and forth inside the coil.
- The lamp will start to light up!
Why did the light bulb go on? By passing a magnet through the coil, you changed the magnetic field it created. These oscillations were felt by the coil, in which the induced current arose.
How wireless charging works
Essentially, wirelessly charging your smartphone or other device works just like we saw in the light bulb experiment. Of course, there is no moving magnet here, but there is an induction coil along which high frequency alternating current.
This current generates changes in the magnetic field. This part of the wireless charging system is called “transmitter coil”. The part located inside your phone is called “coil-receiver”, and a current passes through it in the same way as through the coil in the experiment.
Is wireless charging safe?
Magnetism is always perceived as something akin to magic, because magnetic fields cannot be seen. To build an efficient wireless charging system, you need concentrate magnetic field around the transmitter coil.
This effect is achieved using special materials – ferrites, which conduct a magnetic field much better than air. Therefore, it is easier for the magnetic field to pass through the ferrite, rather than looking for other propagation paths. Thus, outside of charging, the magnetic field is practically absent, and she is quite safe.
Fast or slow?
Can I charge my device with wireless charging as fast as with a wire? A 5W wireless charging system will be able to charge your device at a speed equivalent to a wired charger operating at 5V and 1A.
The latest developments in the field of contactless charging can do this even faster: the phone can be up to 15 W. This greatly reduces the charging time, wireless fast charging is becoming more and more popular.
Which smartphone can be charged wirelessly?
Present on the market today more than 500 device models with support for wireless charging.
Recent Apple models have this feature. Samsung and Nokia also integrated it a few years ago. The Wireless Power Consortium companies also support wireless charging technology. Read more about models that support wireless charging in our other article.
Disadvantages of Wireless Charging
If wired chargers simply disappear between charging cycles, then when using contactless charging, the user faces other disadvantages.
- Depending on the size of the charging surface can be charged two or more devices at the same timebut such chargers are more expensive.
- Charging can be carried out remotelybut you still need to be close to charging – do not take the device further than 4 cm.
- Remote charging takes more timethan the contact method, since electricity is “lost”. Therefore, it is better to keep the phone only on the charger plate.
The Future of Wireless Charging
Currently, the maximum wireless charging power is 15W, so these devices are exclusively for smartphones, cameras, and smartwatches. Wireless Power Consortiumhowever, is working on improving Qi technology so that it can charge devices with larger batteries, such as computers or electric cars.
This technology already exists, it is in the phase of testing and market adaptation. It was developed by the company WiTricity and works on the basis of magnetic resonance technology. In essence, the same thing happens as when charging Qi, but at a greater distance. Since the largest market for electric cars today is in China, the manufacturer mainly cooperates with this country.
- Which phones can be charged wirelessly
- Wireless chargers: which ones are right for your smartphone?
Photo: manufacturing companies