EMC is an acronym for Electromagnetic Compatibility (or Compliance). All electronic devices have the potential to emit and be susceptible to electromagnetic fields. With the continuous increase of electronic device into everyday life, there is a huge potential for devices to interfere with each other. No electrical product or installation design can be considered complete unless all EMC aspects are considered. This is not only important for commonly used consumer products such as television sets, computers, washing machines, etc.; it is especially important for larger commercial products such as vehicles, aircraft, ships, and large industrial installations. Without standardized EMC testing, the consequences of equipment malfunction due to EMC interference could be disastrous in cases such as aviation or automotive applications, where life and safety are at stake. For example, the signal from your cell phone interfering with air traffic control tower signals, or traffic radar affecting the operation of a vehicle’s engine control or braking system electronics.
EMC test standards have been developed to provide defined test processes for testing electronic devices. These standards originating from governmental bodies, manufactures, industry groups, or military requirements are important so that EMC testing is performed consistently between test labs, variables are reduced or eliminated, and test results are reproducible.
Different EMC test standards apply to different product categories or usages. For example, vehicle manufacturers, the aviation industry, governmental requirements, military, medical, commercial, large companies, etc., all follow different EMC standards based on their product’s category. EMC testing ensures a product meets the appropriate standards to sell into a market. When determining the EMC test standard that applies to a product, the first step is to determine the category the product falls into. Secondly, it is important to consider the country where the product will be sold, as test requirements/certifications can vary in different countries.
EMC testing can be broken down into two broad classifications; Immunity tests (also called Susceptibility) and Emissions tests. Immunity testing tests the ability of a product to function normally when being subjected to external signals. This test confirms the product will still work correctly, even if other signals are nearby. Emissions testing measures the magnitude of signals the product is producing and unintentionally emitting; these are unwanted signals being emitted from the product that have the potential to affect other electronic equipment in the vicinity.
Immunity and Emissions testing categories can additionally be subdivided into Radiated and Conducted testing methods. Radiated Immunity testing consists of subjecting a product to external signals radiated from an antenna. Conducted Immunity testing is performed by injecting signals into cables which conduct these signals into the product. In a similar manner, Radiated Emissions measures the emissions that emit from a product, while Conducted Emissions measures the emissions from a product that are directed through cables.
EMC Testing is a necessary step in a product's development cycle since it provides evidence that your product complies with relevant EMC regulations and directive(s). After a successful test program, you can be confident that your product’s reliability will be increased, thus reducing warranty issues, servicing costs, and encouraging brand loyalty. Testing also highlights potential issues or problems with the product that can be fixed before production. Having the right EMC test equipment and design provided by a reliable strategic partner plays a key role in your product's long-term success.
AR has developed some posters to assist you with your EMC testing needs: