Embedded Wireless Charging How Does It Work


Over a century ago, Nikola Tesla changed the world with the invention of the Tesla coil, which showed that electricity can be transmitted through the air instead of requiring wires. Since then, technology developers and other inventors have looked for ways to cut the cord when it comes to charging and powering devices. Newer smartphone models now have the capability of wireless charging.

Scientific Background

Embedded Wireless Charging How Does It Work

Image via Flickr by Didit Putra

When you place your phone or smart watch on a special charging pad, inductive coupling is what allows the device to charge wirelessly. The process uses magnetic fields in two coils to transmit the electric current which provides the charge. In a wireless charging setting, one coil is typically inside the charging pad, and a second coil is in the phone or other device being charged. In order for this to work, electricity must run through the first coil to create the magnetic field, so the charging pad must still be plugged in.

Previous Uses

Wireless charging actually came into the mainstream marketplace in electric toothbrushes. This technology was a necessity because of the danger that exposed electrodes can cause if they get wet. Since a toothbrush is constantly getting wet, electric toothbrush companies couldn’t risk electrocution for their customers, so they designed a way to charge wirelessly and eliminate the exposed electrodes. Developers continued to improve on and perfect the process so that phones and smart watches could charge without wires.

Research and Improvements for the Future

Inductive coupling is ideal for wirelessly charging mobile devices since it doesn’t require a lot of power, but the charging pad and device must be in very close proximity to work. In fact, the range for inductive coupling right now is only a couple of millimeters. A larger diameter of coil and a greater number of windings could increase the allowed distance for charging to still occur, but these changes would require more space in both the charger and the device being charged. Since most consumers are looking for smaller devices for convenience, this isn’t appealing to mobile phone designers and developers.

Scientists continue to do research to improve wireless charging capability. They have found that the inducted current range can be extended by using materials with the same resonant frequencies. As they have tested this theory, the results show that the efficiencies are greatly improved.

Ditch the Cable

Wires and cords just get in the way. You have probably dealt with a tangled jumble of cords or noticed a pet chewing on your charger and realized what a benefit it would be not to have to deal with a charging cord. Wireless charging is the answer. Instead of fumbling around for the charging cable to recharge the battery on your phone, you can simply set it on a pad in a convenient location and it will begin charging immediately. Not all devices have this option, but smartphones such as the Samsung Galaxy S6 Edge has wireless charging capabilities.

Reducing the Cost

When the first wireless charging technology came out, items containing the coils were fairly expensive and the average consumer couldn’t afford them for personal use. After electric toothbrush companies started using the technology in their products, the price went down and it became more affordable. Charging pads for mobile devices are becoming more affordable now as well, so more people will be able to buy them for home and office.

Additional Applications

Other ideas for using improved wireless charging technology include charging electric buses in South Korea at wireless platforms, or adding large pads to public places so that several people can use the power at one time. As scientists continue to improve the distance between the charging pad and the device, they hope to implement wireless charging in household appliances.

With continuous advancements in technology, consumers can look forward to improvements in wireless charging for all types of devices. Even now, using a charging pad instead of a cable is a much easier way to keep your devices charged up and ready to take with you.

Featured image credit: ShutterStock

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