STEPS: inconsistent trace width

[mikeblas]

Why do the high-current traces on the STEPS circuit board reduce their width substantailly before they reach the drill-through hole pad? It seems to me like this defeats the purpose of having wide, high-current traces in the first place.

 

[Garbz]

The more important question is does it matter? Can the ammount of current the STEPS puts out at a given voltage it was designed for burn up the traces?

I personally use massive traces where possible to cut down on the amount of ammonium I need to etch a board.

 

[DaKi][er]

The resistance from those small reductions are completely insignificant compared to if they were thick all the way, you would be struggling to measure the difference without some very serious gear

 

[tangent]

Quote:

Originally Posted by mikeblas It seems to me like this defeats the purpose of having wide, high-current traces in the first place.

Nope. Resistance effects are cumulative, not a "weakest link" sort of thing. The only way necking down a trace like that can cause problems is if the current load would overheat the trace at that point, which we're in no danger of on the STEPS.

The benefit of necking down the trace is that it makes soldering easier, because there's less nearby metal to heat up. The technique is called adding "thermals".