What is Wireless Charging Technology?

Inductive charging popularly known as Wireless charging technology used in modern electronics and electric vehicles is based on the principle of mutual induction between a pair of conductors such that when there is a change in the current flow through one wire it induces a voltage across the ends of the other wire through electromagnetic induction.This is the same principle that is used in transformers.

Cell phones on an inductive charging dock.

In the case of inductive charging devices the conductors are induction coils.The charger has what's called the primary coil used to create an alternating electromagnetic field.The portable or mobile device contains the secondary coil in which the varying magnetic field induces a voltage which in turn leads to current through the coil.This induced current is used to charge the internal cell or battery of the device.

The range of the charger may be increased by using a technique called resonant inductive coupling,wherein the coils used in the charger and the charging device are identical leading to electrical resonance between the coils.This leads to greater range with a slight decrease in efficiency.

A Nissan Leaf being charged by a inductive charger.

To promote compatibility between various chargers and portable devices,the Wireless Power Consortium(WPC) established in 2008 has created the Qi (pronounced "chee") standard for mobile electronic devices.The WPC consists of more than 100 member companies representing wireless power,automobiles,semiconductors,wireless operators,etc...Popular cell phone companies include Nokia,Samsung,HTC...to name a few.The Nokia Lumia 920 is one of the first phones in which this technology has been completely integrated without the need for any additional accessory.

Lumia 920 on a fatboy "pillow" charger.

 Advantages of Inductive Charging:

-Eliminates the need for cables

-Eliminates the compatibility issues     associated with various types of  connectors.

-Lowers the risk of electric shocks.

-Can be used to charge medical implants through skin.

-Can be integrated into  furniture, walls.(coffee shop table,etc..)

-Can be used with devices designed to be sealed or waterproof.

Lumia 820 with a wireless charging shell.

Disadvantages:

-Efficiency is low leading to power loss.

-Heat dissipation is more which can be harmful to certain devices.

-Device cannot be charged when its being used unless its being used on the charger.

-Charging is slower compared to traditional means.