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Engineers’ Angle

Engineers' Angle | What is wireless charging and how does it work?

Published:Sunday | April 7, 2019 | 12:00 AMCarolyn Ferguson/Contributor
In this Monday, May 23, 2016, photo, a Fit2 sits on a wireless charger during a demonstration in New York. The cord connects to the charger rather than the device. AP

Did you know that there are mobile phones that you can charge without connecting a power cable to it? This is done through a process of wireless changing where electricity is transferred to the phone through contact with a specially manufactured base rather than a cable being connected directly to the phone.

The idea of the wireless transfer of electricity has been around since 1831. However, it was not until 2011 that Samsung Electronics introduced the first commercial wireless charging pad for their smartphone after 11 years of research and development. Today, a number of phone manufacturers offer wireless charging-compatible phones, including Apple, Sony, Huawei and LG.

But, just what is wireless charging and how does it work?

Wireless power transfer is done through a process called inductive charging.

There are coils in the charging base that use the electricity received from the power outlet to create a magnetic field, also called an electromagnetic field. This field interacts with a coil in the back of the phone, which then converts the electromagnetic field to electricity to charge the battery. The phone is placed directly on the base for the wireless charging to take place.

As with most technologies, there are standards to guide the safe construction and operation of devices built for wireless power transfer.

The main standard for wireless power transfer is called Qi (pronounced ‘chee’). This is managed by the Wireless Power Consortium. The Wireless Power Consortium is a multinational technology consortium formed on December 17, 2008, and based in Piscataway, New Jersey.

Its mission is to create and promote wide market adoption of the Qi interface standard, used for wireless charging across a number of products. The standard was first released in 2008, and by 2016, it had been incorporated into more than 140 brands of smartphones, tablets and other devices. These devices are clearly identified with the Qi logo.

Some advantages to charging your phone wirelessly include not having to strain the charging port of your phone, and being able to charge your phone anywhere there is a Qi wireless charging pad. No more worries about not having a charger! This makes it very convenient.

However, wireless charging is slower than plugging directly into a wall outlet, making the charging process longer.

What is the future of wireless charging?

Wireless charging is not just for mobile phones. Other devices have and are being developed to use wireless charging. Dell has released a laptop that uses wireless charging. In the future, we can expect a lot more devices that will be available with wireless charging, including kitchen appliances. Imagine having a cordless kitchen. Even BMW now has wireless charging for its electric car, the 530e iPerformance model.

What other devices would you like to see using wireless charging? Share your thoughts through the contact details below.

- Carolyn Ferguson PE, PMP, is an electrical and computer engineer with more than 20 years of experience in telecommunications. She currently lectures in electrical engineering at the University of Technology, Jamaica. Email feedback to