Recently on our blog we have devoted a lot of space to web chargers, especially those that offer multiple charging ports. Power supply of devices requires the use of many cables. An alternative way of supplying power, i. Today we will answer the question how it works. We go back to the year After the stormy period of the Napoleonic wars, Europe finally has several years of peace. The Danish physicist and chemist Hans Christian Oersted notes during his lecture that the compass needle deflects under the influence of the current in the wire.
In this way, he discovered the phenomenon of electromagnetic influence. When Michael Faraday found out about it, he decided to turn magnetism into electricity at all costs. After 10 years of work, in , he discovered a phenomenon that we know as electromagnetic induction.
What does this story have to do with wireless phone charging? Well, thanks to this phenomenon it was possible to develop inductive chargers. But the smartphone charges wirelessly. It just has to be placed on the station. The charging station contains a coil through which alternating current flows.
This electricity generates a magnetic field. When a smartphone is within this magnetic field, it is being charged. Basically, we have to distinguish between two types of charging: inductive and resonant charging. The receiver part of the smartphone also contains a coil, which utilizes the principle of induction. Induction means that a changing magnetic field in a neighboring piece of metal generates electric current. Induction stoves are based on this principle: in this case, a coil in the cooktop generates a changing magnetic field through which electricity flows into the base of the pot.
This causes the base of the pot to become hot. In smartphones, the rapidly changing current is converted into an even current with corresponding circuitry. This current then charges the smartphone battery.
Resonant charging is an extended form of wireless charging. In this principle, there are one or more resonant circuits between the coil in the charging station and the coil in the device. These are electric circuits which consist of a capacitor and a coil which are adapted exactly to suit the respective application. But with all these advantages, resonant charging is more complicated than inductive charging.
For example, it needs more components, which makes it more expensive in practice. It's not only smartphones that can be charged wirelessly. The technology is being used increasingly also for other devices.
These include:. Wireless charging has many advantages for these applications:. In the medical field, wireless charging has benefits with regard to hygiene; devices that do not need a socket for the charge cable are easier to disinfect. Cable lying around are also a tripping hazard — especially where many devices are used, such as in healthcare.
In this area, wireless charging is a considerable improvement. Last but not least, electric vehicles could also be charged wirelessly. The magnetic field creates a current in the coil inside the device sitting on the wireless charger. This magnetic energy is converted to electrical energy, which is used to charge the battery.
While the Qi standard was originally limited to magnetic induction, it now also supports magnetic resonance. It also allows you to place multiple devices on a single charging pad, and have all of them charge at once. Instead, it uses a smaller amount of power and, when it detects a device is placed on the charger, it increases the energy output. Wireless charging is becoming more and more common, and even more standardized. Instead, it chose to support the existing Qi standard, which many other devices also support.
It uses magnetic induction, like Qi. The two are incompatible, though. Wireless charging is based on the principle of electromagnetic induction. This way electricity can be transferred from one device to another without physical contact. Regular applications for induction charging still need the charger and receiving device to be near to each other.
In the electric vehicle industry, induction charging could make it possible for cars to charge without a special socket or cable. In a static charging scenario, the electricity is still supplied by the charging station or Wallbox , but the electric current is sent to the car wirelessly via a charging pad over which the car just needs to be parked.
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