A paper by Advanced Thermal Solutions, Inc., ATS, compiles the major methods used by engineers for measuring thermal conductivity. In all, the paper describes and compares 17 proven methods for measuring thermal conductivity in electronics.

In one section of the paper, these methods are grouped according to the time dependence of the heat applied to the sample. Each method is classified under steady-state, periodic or pulsed. Another section compares the performance of each thermal conductivity measurement method, and provides an idea of sample size and preparation, and the operator skill required. There is also a list of the equipment typically needed to conduct each of these thermal tests.

According to the ATS article, the wide choice of methods may first appear to be a disadvantage. However, once understood for their application-specific benefits the advantages become evident. Materials to be tested, part geometry and part test temperatures will usually be the primary criteria.

As always, the relative cost and expected level of accuracy will also be important factors. Avoiding complicated boundary conditions, irregular part geometry, difficult heater placement/construction and encouraging the difficult task of one-dimensional heat flow will greatly simplify the measurement process. Multiple benefits will result from reducing the cost and assembly difficulty of the experimental set-up while avoiding those errors often introduced when attempting to construct complicated analytical/mathematical models.