What is Electromagnetic Compatibility (EMC)?

The Need

The proliferation of electronic devices into everyday life over the past century, including radios, TVs, traffic lights, security cameras, cell phones and computers (to name a few) has created a need to make sure that different electronic devices can operate without mutual interference. Electromagnetic Compatibility (EMC) testing fills that need by ensuring that an electronic or electrical product shall work as intended within its given environment. An EMC compliant product must:

• Not interfere with other devices in its environment.
• Not be upset by other devices in its environment.
• Not interfere with itself.
• Not malfunction when touched by a human.

A common situation that may shed some light on the need for EMC standards and testing is going to the ATM. When a person walks up to the ATM today, they most likely have their cell phone in close proximity and will be interacting with the ATM by touching it. Along with this, the ATM will have a power cord and will presumably be in close proximity to other electronic devices (i.e.: other ATMs, cell phones, etc.). Because it is EMC compliant, the ATM will function as it should, despite the emissions coming from within its environment from other devices and the human interacting with it. Without EMC, it would be a shot in the dark as to whether everything functioned as it should or not. The interference that impairs performance is known as Electromagnetic Interference (EMI). It is this interference that needs to be reduced to ensure that various items of electrical equipment can operate properly while in the close proximity to each other.

An Overview

There are two main elements to EMC, Emissions and Susceptibility & Immunity. EMI emissions refer to the generation of unwanted electromagnetic energy. Susceptibility refers to the way an item reacts to unwanted electromagnetic energy, while immunity refers to a device's ability to not react with unwanted disruptions.

In the beginning of the 20^th century, the early days of electronics, there were comparatively few electronic devices in use, so, while interference happened, it wasn't much of a nuisance in day to day life. When radio began to gain popularity, the pops, bangs and general noise that users heard in addition to their regular programs was largely believed to be part of the experience of listening to radio. It wasn't until the Second World War that interference began to be addressed. With the increase in electronic equipment being used on warships and the rise of different military weapon and radar systems, the effect each had on one another became a concern.

Because of this, EMC testing began, and continued to grow throughout the decades that followed, with organizations such as the Federal Communications Commission (FCC) creating divisions dedicated to EMC. As technology advanced, so did the need for more advanced testing, with standards beginning to be adopted across the globe in the 1960s and 1970s. With the overall goal of these new measure and standards being that a variety of electronic equipment can operate in close proximity without causing undue interference, testing requirements were adopted relatively quickly.

EMC Testing

With the growing awareness and need to maintain high standards of EMC, many rules have been introduced to help electronics manufacturers maintain electromagnetic compatibility. There are companies all over the world, such as Com-Power Corporation, who are dedicated to making sure that manufacturers and businesses are in compliance. Any new product now needs to have been tested to ensure that it meets the relevant EMC standards. While this can be challenging to engineers and designers, it is important that good EMC practices have been followed to ensure that any new electric device operates as it should under all reasonable scenarios, without interfering with any other devices within its environment.

Conclusion

While Electromagnetic Compatibility is a relatively new practice, its significance in the modern world cannot be emphasized enough. As technology continues to advance, and we become even more reliant on an electronic world, the need to make sure that all devices function properly, without having a negative impact on the devices around it, is of the utmost importance. Designers, engineers and manufacturers are all expected to follow the standards that are laid out by various agencies around the world which allow for the ubiquitous use of electronics with minimal negative interactions.