IEC & Electromagnetic Compatibility

EM Environment  |  Emissions & Immunity  |  Disturbance Types  |  Achieving EMC  |  Functional Safety

The Electromagnetic Environment
Any electrical or electronic device creates an electromagnetic (EM) environment as electrons are moved around to make the device work. In addition, there may be natural phenomena such as lightning occurring in the same location. Or for one of a variety of reasons, an electrostatic discharge may take place even when a device or system is not in its normal functioning mode.

When engineers first became aware of the effects of such phenomena, in the earliest days of radio, they usually referred to radio frequency interference (RFI). Today, the term electromagnetic interference (EMI) better reflects the fact that electrical and electronic systems may cause disturbances at any frequency between 0 Hz and the GHz (microwave) range.

Electromagnetic compatibility (EMC) describes the ability of electronic and electrical systems or components to work correctly when they are close together. In practice this means that the electromagnetic disturbances from each item of equipment must be limited. Equipment must also have an adequate level of immunity to the disturbances in its environment.

The aim of EMC is to ensure the reliability and safety of all types of systems wherever they are used and exposed to electromagnetic environments. So EMC development is closely linked with that of the whole field of electrical and electronic engineering.

EMC issues concerns all of us, not only those who develop, test and manufacture equipment, but also those more "on the receiving end" who rely on, for example, the omnipresent electronic elements in:

• Heart pacemakers
• ABS vehicle braking systems
• Laptop computers
• Air traffic control systems.

For the purposes of its EMC-related publications, the IEC defines the EM environment as "the totality of EM phenomena existing at a given location.

Source: International Electrotechnical Commission (IEC).