EMC is a term used to describe the interaction of electrical and electronic equipment with its electromagnetic (EM) environment and with other equipment. EMC deals with emissions and immunity of electronic devices. All electrical devices generate emission and are susceptible to EM phenomena such as lighting-induced transients, electrostatic discharges, electrical fast transients, radio frequency fields generated by transmitters, and hand-held communication devices. Moreover, an electronic device can be also susceptible to self-generated interferences. A good EMC design will minimize both susceptibility to, and generation of EM disturbances.

Some electronic equipment can be a threat to legitimate users of the radio spectrum, and can interfere with proper operation of other nearby equipment. Most countries place limits on the levels of interference that equipment can generate, and many specify levels of interferences that products must withstand. These levels must be met and test reports obtained before the products can be placed on the market. For example, the most common requirements for Information Technology Equipment (ITE), Telecommunication Equipment and digital devices are often under the scope of FCC (CFR47, Part 15), EN55022, EN55024, and NEBS (GR1089) requirements. Different classes of products may have different legal and functional limits for EMC, however the principles of sound low-noise, low-emission, and high-immunity design are always same.