Wireless Electricity Transmission

Magnetic induction is a technology that you will probably remember from your physics classes at high school.

You need two coils, a transmitter coil and a receiver coil. An alternating current in the transmitter coil generates a magnetic field which induces a voltage in the receiver coil. This voltage can be used to power a mobile device or charge a battery.

The animation below shows how to build a wireless charging system using magnetic induction. Press > to start, and >> to move to the next slide. Take your time to watch the animation before you click the next slide.

You will see that products need more than coils and alternatining currents. For energy-efficient power transfer the phone must be able to shut down the transmitter when the battery is full. The phone, therefore, needs to send control signals to the charging station.

I recommend to look at slide 14 in particular. This slide show three different methods for aligning the transmitter- and receiver coils.