Wireless charging is a technology which enables charging of our devices. In the process of wire, we don’t require the bulky and long USB to attach every time to get our phone charged but through this technology, the power is transmitted through free space.

Wireless charging is the process of recharging battery powered electronic devices without directly tethering using wires and cables to a power source. This process gives users the freedom of charging their phones without the need to plug to power outlet. This means wireless charging enabled smartphones, smartwatches and other devices could be charged by simply placing them on a table for instance or even more complex machines like electric cars can be charged by simply parking them in the garage or by wireless charging enabled road.


Wireless charging works by transferring energy from the charger to a receiver in the back of the phone via electromagnetic induction. The charger uses an induction coil to create an alternating electromagnetic field, which the receiver coil in the phone converts back into electricity to be fed into the battery.

Wireless charging is also known as inductive charging and cordless charging. It is a type of wireless power transfer. It uses electromagnetic induction to provide electricity to portable devices. The most common application is the Qi wireless charging standard for smartphones, smartwatches and tablets. Wireless charging is also used in vehicle, power tools, electric toothbrushes, medical devices. The portable equipment can be placed near a charging station or inductive pad.


Block diagram describes the components of a wireless charging system and charging process. Block diagram of wireless charging are shown in figure below.

fig: Block diagram of wireless charging system.

From the above diagram of wireless charging, it is based on the principle of magnetic induction used in electric power transformers, generators and motors. Electric current through a coil causes a changing magnetic field around that coil which induces a current in another coupled coil. This principle is behind the transfer of electric energy coil in an electric transformer even though the electrically isolated.

From above figure the block diagram of wireless charging each of the components (the transmitter and the receiver) that makes the system possess a coil.


The transmitter coil can be similar to the primary coil while the receiver coil can be compared to the secondary coil of an electric power transformer.


When a charging station is plugged into AC power supply, the powered supplied to DC by the rectifier system after which the switching system takes over. The reason for the switching is to be able to generate the changing magnetic flux needed to induce charge in the receiver coil.


The receiver coil collects the income power and passes it on to the receiver circuit which converts the income power received to charge the battery.


Wireless charging standard refer to the set of rules governing the design and development of wireless devices. The two different standard for wireless charging are as follows.

1.Rezence standard.

2.Qi standard.

1.Rezence standard.

The Rezence standard is based on resonant inductive charging occurs when both the transmitter and receiver coils are in resonance. With this standard devices can achieve a greater distance between the transmitter and the receiver for charging. The standard is being promoted by the alliance for wireless power.

2.Qi  standard.

The Qi standard on the other hand achieves wireless energy transfer using tight coupling between the coils and against the Rezence standard, the transmitter and receiver coil are always designed to operate at slightly different frequencies as it believed more power is delivery using this setup.

The Qi standard is being promoted by the wireless power is an association of two or more individuals companies which includes members like Apple inc, Qualcomn, HTC.

We can select the wireless standard the best suits our application by considering the trade of between the EMI, efficiency and the freedom of alignment between the two standards. Wireless charging are designed to support both the standards these provide high application (systems) are able to communicate and exchange data between devices.

How does wireless charging work with Qi integrated?

  • Firstly check to see if our smartphones supports the Qi wireless charging technology.
  • To charge our smartphone, we need a wireless charger. Position it in a convenient location for instance on our desk.
  • Next, simply place the smartphone on top of the wireless charger and get charging.
  • On both our smartphones and the charging pad a LED indicator shows when our phone is charging.

Applications  for  wireless  charging.

  • Notebooks and tablets.
  • Service robots (e.g. vacuum cleaners and lawn mowers).
  • Smartwatches, Bluetooth headphones and other wearable devices.
  • Electric tools (cordless screw drivers).
  • Electronic toys and drones.
  • In the medical field, wireless charging has benefits with regard to hygiene; devices that do not need a socket for the charge cable are easier too.
  • Cable lying around are also a tripping hazard especially where many devices are used, such as in healthcare.
  • In this area, wireless charging is a considerable improvement.
  • Electric vehicle could also be charged wirelessly. But a lot more energy has to be transferred.


  • The charging socket is no longer used us often and as a result, suffers less wear and tear.
  • If the charging station is always in the same place, we don’t have to look for charging cables.
  • It is simpler and more convenient.
  • No corrosion when the electronics are enclosed away from water or oxygen in the atmosphere.
  • Less risk of electrical faults such as short circuit due to insulation failure especially where connection are made or broken frequently.
  • Wireless charging systems can be operated automatically without dependence on people to plug and unplug. This results in higher reliability.


The following disadvantages have been noted for low power (less than 100 watts) wireless charging devices.

  • Wireless charging also requires drive electronics and coils in both devices and charger, increasing the complexity and cost of manufacturing.
  • Due to the lower efficiency, devices take 15% longer to charge when supplied power is the same amount.
  • Not all devices are compatible with different wireless chargers.
  • The mobile device must be left on a pad to charge and thus can’t be moved around or easily operated while charging.
  • Some standards, charging can be maintained at a distance, but only with nothing present between the transmitter and receiver.
  • Wireless charging is not as efficient as direct charging. In one application, the phone being charged gets hot. Continued exposure to heat can result in battery damage.

These disadvantages may not be applicable to high power that is greater than 5kilo watts electric vehicle wireless charging systems.

Does wireless charging harm battery life span?

The capacity of mobile phone batteries in evitable degrade over time. Some may ask whether wireless charging has a negative effect on battery capacity.

Actually, what will lengthen our battery’s life is to charge is periodically and keep the battery percentage from varying widely, charging behavior that is typical with wireless charging. Maintaining the battery between 45% to 55% is the best strategy.

Is wireless charging safe?

Yes, wireless charging is definitely safe. The electromagnetic field created by a wireless charger is insignificantly little, no more than a home or office wifi network.


Rest assured that we can safely wirelessly charge our mobile device on our night stand and on our office desk.

Wireless charger durability.

Power mat’s charging spots have been in the market for several years, installed in public spaces such as restaurants, coffee shops and hotels. Wireless charging might degrade our battery faster than traditional wired charging. It is durable and long lasting  than the traditional wired charger.



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