Using a smartphone’s magnetic sensor in a low-cost experiment to study the magnetic field due to Helmholtz and anti-Helmholtz coil

摘要

This paper reports on the measurement of a magnetic field due to the coil carrying current by using the magnetic sensor in a smartphone as an alternate to the relatively expensive magnetic sensor probe. The location of the magnetic sensor in the smartphone was known by mapping the value of the magnetic field due to the permanent magnetic bar so that we could obtain an accurate measurement. The variable parameter examined in this magnetostatics experiment was the distance of coils to the magnetic sensor in a smartphone and the magnitude of the current in the coils. The coils used in this research have 8 cm radii and 30 turns of wire, with a 0.3 A current flowing, and the coils were arranged to make a Helmholtz and anti-Helmholtz configuration. The resulting magnetic fields by a coil, Helmholtz coil and anti- Helmholtz coil were measured and compared with the value from calculations using an analytical and numerical approach. According to these results, it can be confirmed that the magnetic field due to a Helmholtz and anti-Helmholtz coil can be measured accurately using the smartphone’s magnetic sensor in a physics experiment.