This module wants to make somewhat clear this problem and to offer practical solutions for estimating the maximum allowed currents (current capacity) of a track or the minimum track width for a specified current.

From the beginning it must be said that what refers to the current through a track, this is limited by two important factors:

•  Heating phenomenon caused by the Joule-Lenz effect.
• Breakdown voltage maximum allowed per length unit.

Usually, the evaluation of the current capacity of the printed circuit tracks can be done by using two well-known methods in engineering: the analysis – situation in which the specialist knows the width of the track and wishes to determine the maximum current through it and the synthesis – case in which it is known the maximum current which has to be transmitted and it is asked for the determination of minimum width of the interconnection track (trace).

The determinations are based on the usage of the graphics appeared in the specialty standards (case 1) or the usage of some formulas of calculus developed in conformity with studies and researches in this domain (case 2).