Radiated emission algorithms for a printed circuit board EMC expert system are described. The expert system mimics the thinking processes that human EMC engineers would use to analyze circuit boards and make design recommendations. Working with limited information about the enclosure, cables or the exact nature of the signals, the expert system evaluates different structures on the printed circuit board looking for potentially strong radiated emission sources. Results obtained from the analysis of a sample printed circuit board are provided to demonstrate how the expert system quickly identifies problems that would otherwise be difficult to locate.