Electromagnetic Compatibility (EMC) tests refer to tests conducted on electronic or electrical equipment in order to ensure that the equipment works as per the manufacturer’s standards, customer demands, and state regulations. A product should provide a smooth experience for its users, without generating in its environment electromagnetic disturbances that can interfere or influence the performance of other products in its neighborhood. The test also checks if the product is able to sustain electromagnetic emissions from other electronic devices nearby.

Strong electromagnetic radiation can cause electric shocks, destroy electrical equipment, damage power distribution transformers, cause fires, and even cause biological hazards. Way back in the WW2 era, electromagnetic interference (EMI) was likened to a gremlin that would take over the controls of a fighter plane during a storm; cut to 2010 – Toyota’s braking problems were because of EMI; even today, mobile phones and passing taxis that are fitted with radios can mess up ABS (Anti-Skid Braking System) and airbag systems of other cars making their driver lose control [1].

This is why EMC tests are very important. Products that fail this test must be recalled immediately or stopped at the customs checkpoint. EMC testing has a long history and has gone from analog to digital, and is still evolving. Let us see how it has changed.

EMC testing is important for military and civilian products
EMC testing is important for military and civilian products


The Evolution of EMC Compliance Testing

Electromagnetic (EM) radiation and EMC testing is older than you can imagine. It all started when man discovered that a lightning strike on a building can cause EM radiation pulses. To fight the problem, lightning conductors were introduced. As the use of electricity spread, equipment got short-circuited, people got shocks, and fires broke out. This led to the invention of circuit breakers.

Possibly, the first observed example of EM radiation interference was in the mid-1800s. Electrical cables disturbed each other and severely interfered with the functioning of telephones and telegraph, among other products, and governments realized the need for curbing EM radiation.

In the early-1900s, it was discovered that EM radiation from vehicles and other sources interfered with radio broadcasts. This was like a wake-up call and all industrialized nations started tackling the issue with serious intent. An international regulatory framework was created to ensure communication remained free from interruptions.

The automobile revolution in the 20th century led to the widespread use of switching devices in cars, motorcycles and appliances. EM interference was observed in radio and TV transmissions, forcing nations to pass EM regulatory laws.

As time passed, we were witness to accidental electrical spark discharges and high RF (Radio Frequency) emissions from microwave ovens. Radiation from new switching devices made governments change their EMC laws and set new standards.

The EMC problem is vast
The EMC problem is vast [OFCOM – UK]
As technology advanced in the 1970s, EM radiation increased with the advent of higher switching speeds, and lower circuit voltages increased the vulnerability of devices. The age of digital electronic equipment was fast approaching, EM standards were being revised and EMC compliance testing had to keep pace.

Likewise, the 1980s saw the introduction of mobile devices and broadcast media channels piling up pressure on the airwaves. However, the silver lining was that digital systems were less prone to EM radiation than analog systems. A lot of parts inside the device could be optimized by software, thereby making EMC compliance easier.

We are in 2013 today and the airwaves are swamped by mobile devices, Internet, broadcast channels, appliances, and more. Luckily we have EMC compliance tests to ensure safety and security.

The EMC standards will keep changing with every invention, and remember, we are in the age of rapid technological obsolescence, and therefore EMC testing has to keep pace with ground realties. Today, EMC testing equipment includes test kits, analyzers, test cells and chambers, RF generators, antennas, ERS (Emission Reference Source), power amplifiers, sniffer probes and more.

Summing Up

EMC tests are a must for all electrical and electronic devices. Many nations enforce EMC standards and in many cases customers demand EMC compliance. Reliable and reputed manufacturers too self-impose EMC standards.

As technology evolves, so will EMC standards and tests. EMC testing has evolved to a great extent and has no other option but to keep pace with technological changes.

* source Emscan


About The Author

LBA Group, Inc. has 50 years of experience in providing RF asset solutions and risk management for industrial and telecommunications infrastructure assets. The group is comprised of LBA Technology, a leading manufacturer and integrator of radio frequency systems, lightning protection and EMC equipment for broadcast, industrial and government users worldwide; the professional consultancy Lawrence Behr Associates and LBA University, providing on-site and online professional training. The companies are based in Greenville, N.C., USA.

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