With inductive charging technology, the charge passes between a transmitter and receiver coil placed closely together, usually only separated by the outer casing of the two devices (<7mm). The coils must be aligned to make the connection, making inductive charging great for direct-contact applications. Some Qi transmitters use a multi-coil system, eliminating the need to align the device on the charging area.
Qi resonant wireless charging builds on the benefits of inductive charging by removing the close-contact requirement. The transmitter can detect and charge existing Qi receivers at greater distance (up to 45mm). This spatial freedom makes resonant charging perfect for applications such as mounting a charger under a table, desk or embedding technology deeper into a device.
Qi encompasses the benefits of both inductive and resonant charging technologies in a versatile standard that eradicates dead battery. Because inductive and resonant technologies have unique use cases and benefits, Qi products are incorporating both to offer the innovative services and features in the most energy-efficient and cost-effective possible.