Improvement of measuring accuracy of magnetic field strength in single sheet testers by using two H coils

The accuracy of the measured magnetic field strength of single sheet testers using an H coil[1-4] is examined by finite element analysis. An improved measuring method which uses two H coils is proposed from this investigation. It is clarified that the best measuring method of magnetic field strength is the improved two H coil method. The validity of the new method is confirmed by experiments.