How is electromagnetic induction applied in wireless charging?

Wireless charging utilises electromagnetic induction to transfer energy between two objects through an electromagnetic field.

In more detail, electromagnetic induction is the process by which a circuit can generate a voltage or current due to a change in the magnetic field. This principle is the basis for wireless charging technology. The charging station, also known as the primary coil, creates a time-varying magnetic field. The device to be charged, which has the secondary coil, is placed within this field. The changing magnetic field induces an electromotive force (EMF) in the secondary coil, which in turn generates an electric current. This current is then used to charge the device's battery.

The primary coil and the secondary coil are not physically connected. Instead, they are coupled through the magnetic field they share. This is why this method of charging is termed 'wireless'. The efficiency of the energy transfer depends on the proximity and alignment of the two coils, as well as the frequency of the change in the magnetic field.

The wireless charging technology is based on Faraday's law of electromagnetic induction, which states that the EMF induced in a circuit is directly proportional to the rate of change of magnetic flux through the circuit. This means that the faster the magnetic field changes, the greater the current that is induced in the secondary coil.

Wireless charging is a safe, convenient, and increasingly popular method of charging devices. It eliminates the need for physical connectors and cables, reducing wear and tear on device ports. However, it's important to note that the efficiency of wireless charging is generally lower than that of traditional wired charging, due to energy losses in the electromagnetic field. This is a key area of ongoing research and development in the field of wireless power transfer.