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Electromagnetic compatibility, in short also called EMC, is an essential aspect of modern electronics, and it ensures that devices function properly without causing or being affected by interference from other electronic signals. EMC helps electronics meet regulations and allows them to peacefully coexist in the busy world of electromagnetic fields.
The function of EMC essentially is to make sure of three things:
It is to ensure electronic devices do not emit unwanted electromagnetic energy.
Two, it is to make sure that electronic devices meet certain levels of immunity to external electromagnetic influences.
To ensure that the device does not generate interferences within itself.
This is essentially where EMC begins. Understanding EMC begins with the fundamental principles of electromagnetism. Electromagnetic fields are generated by electrically charged particles and can affect the behavior of other nearby objects. In the context of electronic devices, these fields can originate from various components such as processors, digital circuits, and power supplies.
The History and Evolution of EMC
Electromagnetic compatibility has come a long way since electrical and electronic engineering started. It all began in the late 1800s and early 1900s, when radios and electronic devices were taking off. Back in the early 1900s, when radio communications were booming, interference became a big problem.
Equipment like spark gap transmitters, commonly used in radios, caused a lot of interference across different electronic devices. This was the start of EMC worries, mainly about radio frequency interference, also called RFI.
During World War II, the use of radar and other electronic gear in warfare brought attention to electromagnetic interference issues. This led to the first guidelines for EMC aiming to reduce interference among military equipment. After the war, as technology boomed, more electronic devices flooded civilian life, making EMC important not just for the military, but also for civilians.
Over the years, technology has greatly changed electronic devices. In the 1950s, the bipolar transistor was introduced, followed by integrated circuits in the 1960s and microprocessors in the 1970s. As devices became smaller, the signals they used also became smaller, needing shorter communication times and higher frequencies.
Before, electronic devices used vacuum tubes as switches, which were bigger and slower than today's technology. In the late 1970s, digital signal processing became popular, replacing slower analog signal processing with faster digital signals. But this shift also affected the signal spectrum used by devices.
EMC Standards and Regulatory Bodies
With more digital signals, the frequency spectrum became more crowded and harder to manage. Faster digital electronics meant more potential for interference, due to the rich harmonic content of these signals, so EMC became crucial in electronic design.
Organizations like the FCC and IEC started setting standards to manage EMI. Other committees, such as the CISPR, were also formed. CISPR formed in 1934, which stands for the International Special Committee on Radio Interference, takes this name from its French translation.
It is a specialized committee within the International Electrotechnical Commission or IEC focused on setting international standards for electromagnetic compatibility and radio frequency interference in today's world. EMC is very important for all electronic devices, especially because as technology advances, devices become smaller and more densely packed, increasing the risk of electromagnetic interference.
Devices need to maintain EMC to function properly and avoid interfering with nearby electronics, as well as within themselves. With the rise of wireless communication, and the Internet of Things, or IoT, EMC becomes even more important, as devices need to work together seamlessly in a crowded electromagnetic environment.
Understanding EMI and Its Relationship with EMC
One thing we need to clarify is the confusion between EMC and EMI.
EMC, or electromagnetic compatibility, is a term used in electronics to describe the ability of a device or system to operate without interfering with other nearby devices or being interfered with by them due to electromagnetic radiation.
EMI stands for electromagnetic interference. It refers to the disturbance caused by electromagnetic radiation from an external source that affects the performance of an electronic device or system. EMI can manifest as noise, distortion, or even complete failure in electronic equipment. It can be caused by various sources, such as nearby electronic devices, power lines, radio signals, or electromagnetic radiation from natural sources.
EMI is the unwanted interference itself, while, EMC is the ability of devices to tolerate and function properly in the presence of such interference. Electromagnetic interference (EMI) deals with controlling the electromagnetic interference emitted by electronic devices.
🔓 It's important to limit EMI to prevent devices from disturbing nearby equipment.
This division involves understanding and managing EMI sources like power lines, radio frequencies and digital signals. Electromagnetic immunity or susceptibility, on the other hand, is the part of EMC which focuses on how well a device can function when exposed to electromagnetic fields and ensures that electronic devices can still work properly, even when facing external electromagnetic interference.
This is important as the number of electronic devices around us increases, making the electromagnetic environment more complex and challenging.
Why is it so important to address EMC and contain EMI at an early stage of our product design?
System-Level EMC Design Approach