Choosing the track width on PCB.

On January 21, 2012, in Cmc-CNC, Misc, by Cmc

From time to time it happens that one needs to actually transmit real currents trough PCB tracks. Until now I always thought that it is a good idea to calculate the real resistance of PCB track and then make sure if the requirements fit. But as anyone with any PCB design background should know, the PCB design is not a linear process. So I decided to find out how should one decide on PCB track current carrying capabilities


According to “Circuit designers companion”  one should take calculated resistance etc  mostly only as reference values since manufacturing tolerances can be pretty wide and account two to one variation in final value.  Also the temperature coefficient of copper means that resistance will vary by several percent over the typical ambient temperature ranges and also with self heating.

Also the book provides us with a nice graphic on safe currents in PCB with also accounting the main thicknesses of the copper.

Figure 2.4 Safe currents in pcb tracks


I would say that this is really a nice and useful info-graphic that could be useful for many and more beginners. .

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