Practical remark: An exfoliate track will accept a smaller current than a track disposed and fixed on the dielectric substrate because in this case the transfer of the heat will be done practically only by the convection mechanism, not by the conduction too.

At the end there are shown two approximate formulas useful for interested specialists. The first one, derived from the above relations, allows the calculus of the over-temperature so the determination of the temperature of an interconnection track in the conditions of knowing the track resistance, width, intensity of the current that passes through it and temperature of the surrounding environment.:

 

The second formula it refers at the calculus of the linear resistance of a track. In order to obtain this measure we can follow two ways: first one is the classical one in conformity with the knowledge accumulated during high school at physics and won’t be presented here. The second way it is based on data from the volume “CRC Handbook of Chemistry and Physics, edition no.64 page F-119” and determines the resistance of a copper interconnection track by the formula:

  

where: T-temperature [°C];

           A-transversal area of the interconnection track [mil²].