As we have reminded earlier, there exist a lot of situations in which not the area is important but the measures that drive to it:

  

where: W – track width [mil];

              t- track thickness [mil].

It results that:

  

parameters n1 and n2 being different just to put in evidence the different transmission of heat.

Due to the usage of some special mathematical techniques, the parameters above could be determined and the calculus formulas became the following:

 

for PCB structures having the thickness of the copper foil of 35μm and 175μm and

  

for PCB structures having the thickness of the copper foil of 70μm.