Chapter 8 Low frequency tests
The concept of EMC applies not only to high frequency phenomena. A product must be compatible with its electromagnetic environment, and there is no limitation on the frequency range encompassed by that environment, nor on the modes of coupling with it. A universal requirement is that the product should be compatible with its power supply; that is, it must be adequately immune from variations in the power supply, and it must not itself cause such variations. This is necessary whether the supply is DC, AC 50Hz mains or some other system-specific description, but for the public AC mains there are a number of common requirements which apply under the umbrella of the EMC Directive and which are discussed here.