Wireless charging coils are components used in wireless charging systems to enable energy to be transmitted between two coils without the need for any physical connection between the transmitter and receiver. These coils, which are effectively electromagnets, create an alternating magnetic field which creates a current in the receiver coil, and hence, charges the device. These coils come in two types – air-core and ferrite-core. Air-core coils don’t need any iron in them and are lighter, but they also reduce the charging efficiency and extend the charging time. Ferrite-core coils, on the other hand, are more thermally efficient and more efficient in transferring energy, but they are heavier and more expensive.