On A Long-Term Survey of The Magnetic Field In A Laboratory

In this paper we conducted a study referring to survey of background magnetic field in a laboratory of Electrical Engineering Faculty, where students carry out didactic activity. Based on three sets of measurements made in the 2017-2023 period, a characterization of the main field sources and the background magnetic field was performed. During this period, the power supply network has suffered some changes, and in terms of the used instruments, it was switched from spot measurement performed with commercial instruments to continuous long-term surveys performed with automatic survey systems made and calibrated by authors. In addition to considering the spatial variation of the magnetic field, the study determines and analyzes the temporal variations of the background magnetic field, namely the daily, weekly and monthly variability. Thus, a great temporal variability of the magnetic field was identified with the week days and even months, can be reached in the ratios between the magnetic field averages on the week days and on the months of the year of order 4/1 or even 5/1.