Before going into details on Würth Elektronik power charging coils, the engineer would like to show how wireless power charging works. The Power is transferred ‘wirelessly‘ through an inductive coupling at a short range. Typically only a few millimeters max. The transmitter and receiver coils are inductively coupled, which means that the AC current in the transfer coil generates a magnetic field which induces a voltage in the receiver coil. The receiver voltage will then be used to power a device. The magnetic field is highly concentrated in-between the transmitter and the receiver, which allows users to be only exposed to a small leakage field which is then minimized by an EMI shield on the back of the coil. The coupling effect is influenced by the following factors: matching coil size, a flat surface between transmitter and receiver, as well as the shielding and the alignment of the coils.