Wireless chargers for the smart device are relatively new as compared to old wired chargers methods and as wireless chargers work on the principle of EMF to charge your device, it is very easy for the general public to consider the potential health hazard due to their EMF.
With advancing technology wireless chargers are going to be a common charging method shortly, so answering the question “Are wireless devices safe?” is very important now.
How Do Wireless Chargers Work?
The concept of wireless charging evolved in the 19th century when Nikola Tesla gave the idea of magnetic coupling.
Magnetic coupling is a phenomenon in which electricity can be transferred through the air with the help of changing magnetic fields between two circuits i.e. a receiver and a transmitter.
The phenomenon of wireless charging is more than a century old but its usage in new cellular devices namely Samsung and Apple mobile phones, laptops, and other kitchen appliances has given it a new life.
In wireless charging, the receiver (an electromagnetic or induction coil) is placed inside the device. The transmitter (charger) also uses a similar coil through which a changing current is passed.
The changing current creates a varying magnetic field in the charger’s coil which is received by the coil in the device and hence an EMF is produced. The EMF is then passed on to the circuits to charge the device.
What Certifications Should I Look For?
The trend of wireless charging is increasing due to the progress of technology and hence the knowledge of certification is very important before using wireless chargers to know whether the product is certified or not.
The certification authority makes sure that a product is compatible and safe. Devices that use transmitters and receivers with the function of wireless charging fall under the Radio Equipment Directive (RED) and must meet its requirements along with QI pronounced as “chi” and Made for iPod MFi certification.
RED provides different radio and electromagnetic compatibility standards for wireless power and transfer (WPT) devices that must be met for approval from the RED regulatory authority.
Radio standards of RED look into the effective use of spectrum i.e. operating frequencies and their range, H-field requirements, and unwanted emissions whereas interference Emissions and immunity are taken into account through Electromagnetic compatibility EMC standards.
Devices certified by QI deliver safe and efficient wireless charging. A device that is QI certified undergoes rigorous independent testing to help ensure, interoperability, safety, and energy efficiency.
Moreover, different countries have local authorities that provide permits to WPT devices based on their criteria.
Common Mistakes with Using Wireless Charges:
There are a few very common mistakes that people commit while using WPT devices.
1- When people hear the word “wireless”, they immediately think that they can move their device pretty freely while it is being charged but this is not the case.
You are not allowed to move your phone away when it is being wirelessly charged which is a disadvantage compared to wire chargers.
2- Improper placement of the device on the transmitter pad may also lead to a poor connection between the transmitter and receiver. Hence, the device should be properly placed on the pad without any obstruction.
3- If the device is inside a case, you may need to remove the case for the proper connection of the device with the charger.
4- The device’s case should not be made of metal if it has to be wirelessly charged.
5- You cannot use the device during charging otherwise it will stop charging.
6- Very few wireless chargers have fast charging mode and it will only work if both charger and device are made by the same manufacturer.
Wireless Chargers and EMF Radiation:
Wireless charges are a source of electromagnetic radiation and fortunately, many studies have been carried out to investigate the EMF intensity and its effect on human health.
The studies have proved that electromagnetic ranges at which wireless chargers work are not big enough to cause any significant damage.
Moreover, WPT devices use pads for charging and they emit radiation only when a device is in contact with the pad. So, these chargers don’t emit anything when the device is not in contact with them.
When wirelessly charged devices are being charged, radiofrequency exposure is usually substantially lower than FDA, FCC, and International limits.
The advancement in the field of wirelessly charged devices in the form of fast chargers and charging over longer distances may pose a serious threat to the environment and human health in the future.
How much EMF radiation do wireless charges emit?
Exposure to EMF for a longer duration of time can cause serious health issues. Wireless chargers that employ magnetic induction create a very small electromagnetic field that is only a few millimeters wide and is between 5 and 15 watts.
When a wireless charger is plugged in and a phone is placed on it, the amount of electromagnetic emission is around 3 milligauss (mG).
For reference, electromagnetic radiations above 1mG are considered unsafe for the human body. Moreover, according to research carried on by EMF academy, it is found that wireless chargers emit 0mG of electromagnetic radiation when they are not charging a phone.
As the magnetic field produced by wireless charges is only a few millimeters or inches wide, it almost does not harm our health.
Types of Wireless Chargers and Their Radiation:
There are three types of wireless charges i.e. tightly coupled electromagnetic chargers or non-radiative chargers, loosely coupled electromagnetic resonant chargers, and uncoupled radio frequency chargers.
In tightly coupled charges, a varying current is used to create a changing magnetic field which is induced in the receiver circuit where required EMF is produced to charge the device. Tightly coupled chargers emit almost no radiation.
In loosely coupled chargers, resonant coils are used to have a strong coupling between the receiver and transmitter tenth of centimeters apart from each other. They emit EMF over a longer distance.
Uncoupled RF wireless chargers transmit power over a distance of a few meters. This type of device emits energy in the form of EMF waves or radio frequencies which are converted to electricity by the receiver to charge the device.
This type of charging has not been deployed in the market yet and can be the most dangerous way of wireless charging among all three.
How to Protect Yourself from Wireless Charger’s EMF
The wireless charging phenomenon can be based on magnetic induction, magnetic resonance, or radiofrequency.
The most harmful of all these is radiofrequency charging but fortunately yet no device working on radiofrequency has been deployed in the market for wireless charging purposes.
Devices based on magnetic induction emit almost no electromagnetic radiation. Moreover, devices that employ magnetic resonance can emit EMF above the desired level in a radius of 2-4cm.
Hence the best way to keep ourselves safe is to maintain a sufficient distance when a device is on a charger. Whenever the transmitter (charger) and receiver (devices) are not in contact with each other, there are no electromagnetic radiations which is a big advantage.
Moreover, advancements in this field i.e. fast chargers, wireless car charging, etc. can cause serious threats in near future.
Myths about Wireless Chargers
There are several misconceptions about the use of wirelessly charged devices. A few of these are mentioned here.
Damage to your device
Wireless chargers don’t damage your devices if you use a good quality and QI-certified charger.
It is not true that old devices cannot be wirelessly charged because they don’t have any electromagnetic receiver coil inside them. But the truth is a third-party add-on can do this job for you.
Turning off your device
It is not required to turn off your device while it is being charged to avoid any damage to it.
Not all third-party or off-brand charges are faulty. But yes, one should be able to differentiate between a fake and an off-brand charger. If a third-party charger is manufactured according to the set standard, it must work well.
Charging the device for a longer period
Wireless charging systems are intelligent enough to disconnect the power when the device is fully charged. But one should avoid keeping his or her device on a charging pad for unreasonably extended periods to avoid the heating of the device.
As wireless chargers are a relatively new method of charging your smart device and they work on the principle of EMF, they are associated with EMF-related health hazards.
Studies have shown that due to low power rating and a weak EMF field that does not influence or affect any device that is more than 4 to 5 centimeters away from the charger, the ability of wireless chargers to be a health hazard due to their EMF is almost zero.
Different types of wireless chargers available that work on different methods have a small range and they cannot affect any device that is a few centimeters away from them but work is in progress to develop wireless chargers that can charge devices from a few meter distance.
They will surely have a strong EMF field and thus can affect human health. So wireless chargers, for now, can be considered safe to use for your smart devices.