Amid the wave of global trade integration, Electromagnetic Compatibility (EMC) has become a "passport" for electrical and electronic products to access international markets. As a major global trading bloc, the European Union adopted Directive 89/336/EEC (the EMC Directive) as early as 1989 to unify EMC regulatory requirements among member states. Its purpose is to eliminate trade barriers caused by divergent national standards and ensure the free movement of products within the EU market.
The directive underwent two revisions via 92/31/EEC and 93/68/EEC. The latest current version is 2014/30/EU. Compared with older editions, its core revised highlights include: first, strengthened market surveillance with clear liability of member states for tracing and recalling non-compliant products; second, streamlined conformity assessment procedures that allow enterprises to complete certification through self-declaration combined with third-party testing; third, expanded coverage scope of applicable products to include emerging electronic equipment such as smart wearable devices and IoT terminals.
Since 1 January 1996, the EU has formally mandated that all electrical and electronic products pass EMC certification and bear the CE marking. This measure has not only reshaped the access rules for Europe’s electronics market, but also fostered a global consensus on mandatory EMC administration. Major economies including the United States, Japan and China have followed suit and established EMC supervision systems tailored to their respective markets.
Essentially, Electromagnetic Compatibility (EMC) refers to the capability of equipment or systems to "coexist without mutual interference" in complex electromagnetic environments, which can be broken down into two core dimensions:
(1) Electromagnetic Interference (EMI): External interference emissions from equipment
It refers to unwanted electromagnetic signals generated during equipment operation, which may disrupt the normal operation of other devices. Classified by propagation paths as follows:
Conducted Emission (CE): Electromagnetic interference propagated through conductors such as power cords and signal cables. For example, transient pulses released into the power grid via power lines when a refrigerator starts up.
Radiated Emission (RE): Electromagnetic interference transmitted via spatial electromagnetic waves. For instance, electromagnetic waves radiated by a working microwave oven may interfere with nearby wireless walkie-talkies.
(2) Electromagnetic Susceptibility (EMS): Equipment’s immunity against external interference
It denotes the ability of equipment to maintain normal functionality when exposed to external electromagnetic interference. Categorized by interference sources as follows:
Conducted Susceptibility (CS): Immunity to electromagnetic interference coupled through conductors, e.g., the capability of industrial machine tools to withstand power grid voltage fluctuations.
Radiated Susceptibility (RS): Immunity to spatial electromagnetic wave interference, such as the capacity of car navigation devices to deliver accurate positioning near mobile phone signals.
Electrostatic Discharge (ESD) Immunity: Resistance against electrostatic discharge interference, for example, the performance that a computer mainframe does not crash upon human contact.
Electrical Fast Transient / Burst (EFT/Burst) Immunity: Immunity to sudden high-frequency pulse interference in circuits, commonly tested for interference generated by relay switching operations.
Power Frequency Magnetic Field (PFMF) Immunity: Resistance against power frequency (50Hz/60Hz) magnetic field interference, such as stable operation of medical devices near transformers.
