How does a wireless charger charge a phone?

Instead of plugging your device into a charging cable, a special wireless charging pad transfers energy to your device using electromagnetic induction (also known as “inductive coupling”). It doesn’t replace charging with a cable — all phones that support wireless charging can still be charged the traditional way. Wireless charging uses electromagnetic fields to transfer energy from a charging pad or mat to a compatible device, such as a smartphone, without the need for a physical connection.

Here’s a simplified explanation of how wireless charging works:

when a charging pad or base station is connected to a power source, the alternating current (AC)  flowing through the coil in the charging pad generates a magnetic field. After we place a device, e.g. a smartphone on the charging pad ,this magnetic field induces a voltage in the coil of the device’s receiver through a process of electromagnetic induction.  The induced voltage in the receiver’s coil is converted into direct current (DC) by internal circuitry which is then used to charge the device’s battery.

By understanding the theory of wireless charging, we can easily figure out why we need to align our smartphone with the wireless charging pad during the charging process. On one hand, it will maximize the charging efficiency and reduce the energy loss. If the coils are not aligned, the magnetic field may not be properly coupled, resulting in reduced power transfer efficiency. On the other hand , proper alignment helps ensure safe charging. Wireless charging systems often have built-in safety mechanisms to prevent overheating. When the device is aligned correctly, the heat generated during charging is distributed evenly. If the alignment is off, it may lead to localized heating, potentially causing safety concerns.