PURPOSE The purpose of this standard is to eliminate confusion@ by providing definitive statements of the conventions involved in determining the polarity of a magnetic field@ and by describing basic practical methods that may be used@ with necessary precautions. While it might be considered that the conventions are basic text-book material@ it is found that few text-books state them explicitly@ and disagreement among engineers is observed as a result. Since some electrical or electronic devices may be destroyed@ if the magnetic field polarity is incorrectly determined@ it is important that disagreement or confusion be avoided.