The AC Helmholtz coil is designed for the power frequency magnetic field immunity test, and it complies with the GB/T 17626.8 standard. AC Helmholtz coils should produce a magnetic field of strength corresponding to the selected test level and the specified uniformity. The magnetic field strength can be scaled up to 2 kA/m and is customizable. The AC Helmholtz coil is made of nonmetal, nonmagnetic material, and its cross-sectional and mechanical structure are stable and conducive towards coil stabilization. Its design allows it to surround the device under test (DUT) in three mutually perpendicular orientations. Customizing different sizes of power frequency coils based on the size of the DUT can produce a uniform magnetic field across the entire bench or vertically with a deviation of ±3 dB. For smaller devices, the standard-sized induction coils are squares with a side length of 1m, or a circle with a diameter of 1m. The standard square coil has a test area volume of 0.6*0.6*0.5m³ and can be replaced with a double coil with volume 0.6*0.6*1.0m³ for larger volumes. In order to adapt to the magnetic field test in three mutually perpendicular directions, the AC Helmholtz coil can be rotated from 90 to 360 degrees, and the sample table can be rotated 360 degrees.