Electromagnetic Compatibility And EMC Testing

From the time of the first electrical circuits, systems and devices engineers have had to worry about electromagnetic compatibility or EMC. This is the generation or production and subsequent reception of radio frequency and electromagnetic interference that occurs when different electronic devices are in the same area.

With multiple electric fields in one area, the risk of negative effects increases. This risk can include something relatively minor such as static or slow data transfer, or it can result in actual data loss. In some conditions, it can result in device failure, which is why EMC testing is so important.

Emissions and Immunity

Through EMC testing in the design and development of a component or device, it is possible to address the two potential risk factors. One is the emission of electromagnetic energy from any electrical component or device. This testing allows engineers to modify the design to keep any loss, dissipation or emission of electromagnetic energy within the standards developed.

With testing on this component of EMC, devices that meet standards can be introduced into environments with other electronic devices without the concern of an unintentional generation of EMI or RFI that can disrupt or destroy the equipment.

The second consideration is the testing for susceptibility or the reaction within the electronic components or systems of a given device when exposed to electromagnetic energy. The more the design is able to provide immunity to the device from this type of exposure the more effective and “immune” the device will be.

As there are always some forms of electromagnetic interference present, it is the balance of limiting the unintentional production of EMI and RFI while also designing or hardening the equipment to be resistant to this exposure.


The specific EMC testing used on a component or piece of equipment will be a factor of the applicable standards required as well as the susceptibility and emissions testing protocols.

Most testing for RF or radio frequency is completed in a specialize lab, while for other types of devices, such as those used in automobiles or large telecommunication systems, the testing may be done on-site. These sites are often part of the standards, which ensures all devices tested are under the same environmental conditions.

Before any testing is completed the testing equipment has to be correctly calibrated and configured. Depending on the specific type of test different testing equipment may be used and the tests will be repeated for verification and for reporting purposes.

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