Radiated Emissions

Determining Relevant Standards

Radiated emission is the Radio Frequency (RF) energy produced and unintentionally emitted by a product. The type of equipment you manufacture, and the countries in which you intend to ship, will determine the standard for radiated emissions to which your product must comply.

Common emissions standards, which include limits for both radiated and conducted interference, are:

  • FCC Part 15 for almost all digital devices shipped in the United States
  • EN 55022 for computer equipment sold in Europe for use in a residential or commercial setting
emissions tables

Conducted Emissions

Conducted emissions refer to the RF energy conducted out of a device through its power cord or data line.

Power Line Harmonics and Voltage Flicker

Operation of AC/DC power supplies creates harmonic currents (i.e. currents at frequencies that are multiples of the AC supply frequency of 50Hz or 60Hz). These currents can create problems in electric motors and other electrical devices. Power utility companies in Europe have lobbied for the implementation of standards to limit the amount of harmonic current and voltage devices produce. This has resulted in the IEC/EN61000-3-2 standard, which becomes mandatory in the year 2001 for almost all types of equipment that draw less than 16 amps per phase.

Voltage fluctuations, called Voltage Flicker occur whenever a high current load is switched on or off. A common example of this is the flicker of the lights caused when a household iron or refrigerator switches on.