Significant changes in the inductance value may be caused by the following external factors:

Temperature changes: The inductance value of an inductor is closely related to the magnetic permeability of the magnetic core material, and temperature has a significant impact on the magnetic permeability. Generally speaking, when the temperature rises, the magnetic permeability of the magnetic core material will change, resulting in a change in the inductance value. For example, for a ferrite magnetic core, at a higher temperature, the magnetic permeability may decrease, thus reducing the inductance value. In addition, high temperature may also cause the winding wire of the inductor to expand, resulting in a relative decrease in the number of winding turns, which will also cause a change in the inductance value.

Mechanical stress: When the inductor is subjected to mechanical stress, the magnetic core may be deformed, thereby changing the length and cross-sectional area of the magnetic circuit, affecting the distribution of the magnetic flux, and leading to a change in the inductance value. For example, during transportation or installation, the inductor is subjected to impacts, squeezes, or vibrations, which may cause slight deformation of the magnetic core and cause a significant change in the inductance value.

External magnetic field interference: If there is a strong magnetic field around the inductor, the external magnetic field will interact with the magnetic field of the inductor itself, interfering with the distribution of the magnetic flux, and thus changing the inductance value. For example, when the inductor is close to strong magnetic field devices such as large motors and transformers, it may be affected by their magnetic fields, resulting in a change in the inductance value.

Influence of humidity: In a high-humidity environment, the surface of the inductor's winding may adsorb moisture, reducing the insulation performance of the winding and increasing the equivalent capacitance, thus affecting the high-frequency characteristics of the inductor and causing the inductance value to change in the high-frequency band. In addition, when the magnetic core material is exposed to a humid environment for a long time, it may get damp, and its magnetic properties will also be affected, which in turn causes a change in the inductance value.

Change in installation position: Changing the installation position of the inductor may change the distribution of the magnetic medium around it, or change its relative position to other magnetic components, thus affecting the inductance value of the inductor. For example, moving the inductor from a position far away from a metal object to a position close to a metal object, the shielding and scattering effects of the metal object on the magnetic field will change the magnetic field distribution of the inductor, resulting in a change in the inductance value.