Inductive Thermal Sensitivity
Fractional change in the inductance of a component per degree of temperature variation defines the stability of a magnetic sensor. Temperature coefficient of inductance is a critical specification for coils used in resonant circuits. Designers must account for this factor to ensure that sensors remain accurate across their entire operating range.
Dimensional Expansion
As a coil heats up, the copper wire and the winding form expand, which changes the geometric area and the turn density. This expansion typically increases the value of the temperature coefficient of inductance. If the coil uses a ferrite core, the permeability of the material also varies with heat.
These effects combine to create a non linear shift in performance that varies across the thermal range.
Balancing Method
Engineers often select capacitors with a temperature coefficient that is equal and opposite to that of the coil. This matching minimizes the drift of the total resonant frequency. Then the temperature coefficient of inductance is effectively cancelled out for the specific application.
Software compensation using a local temperature sensor is another common approach for high precision instruments.
Environmental Testing
Characterization involves measuring the inductance at several stable temperature points within a controlled chamber. The slope of the resulting curve provides the coefficient value. This test must be performed under the same electrical conditions as the final application to be valid.
