Need to charge your phone? Just plug it in. But what if you could charge it without wires, transmitting electricity through the air to your phone? It’s no pipe dream: on many modern phones, you can charge your devices without wires using a wireless charger.
Samsung offers this feature built into the Galaxy S7 phone: put it on the optional $60 Qi charger and it will charge away without wires. It’s not just phones, though — other small portable electronics use similar systems. Apple uses it on the Apple Watch and may be planning to add this feature to the next version of its iPhone. So, how do these systems work? Let’s take a look at the science of wireless power.
There are two main wireless charging standards: Qi (from an industry group called the Wireless Power Consortium) and Airfuel, created by a group called the AirFuel Alliance which includes companies such as PowerMat. Although they differ in the specifics, both work using an approach called resonant inductive coupling. In these systems, the power is transferred between two coils of wire: one in the charging base, and one in the device.(More…)