Anything else whatsoever... Keep it clean though.
By apollard
#13688
OK, perhaps I am missing something. Playing with the calculator, changing the ambient temp does not affect the trace width at all. Only the voltage drop and power change. Even going to extremes ambient doesn't affect the trace width calculated.

Raising ambient temp for a wire or cable results in de-rating the current it can carry. This is because the heat rejection per unit time in the wire is less at higher ambient temps, resulting in a higher temp rise for a set current flow. The FAQ on that site says the trace width is determined to maintain temp rise to the entered value. So why would a higher ambient not result in a larger trace?
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By cx500tc
#13694
apollard wrote:OK, perhaps I am missing something. Playing with the calculator, changing the ambient temp does not affect the trace width at all. Only the voltage drop and power change. Even going to extremes ambient doesn't affect the trace width calculated.

Raising ambient temp for a wire or cable results in de-rating the current it can carry. This is because the heat rejection per unit time in the wire is less at higher ambient temps, resulting in a higher temp rise for a set current flow. The FAQ on that site says the trace width is determined to maintain temp rise to the entered value. So why would a higher ambient not result in a larger trace?
Wires and traces exposed to ambient air cool off faster. That is why you don't see much, if any change in trace width calculations. I'm almost certain that if you calculated trace width for a captive trace, i.e. a trace in the 2nd or 3rd layer of a 4 layer board, you would see what you think / expect.

Note the word you used: "maintain". That is actually a misnomer, as that temp rise is the "limit", i.e. the smallest trace width possible which limits the trace temperature rise to that degree. If you set ambient to 25C, and temp rise to 35C, it will calculate the trace width necessary to limit the trace temp to 60C, or 35 above 25.

Those calculators also limit trace widths to common sizes, generally choosing the next largest one which meets your criteria.
By dazq
#21847
The problem with the mini versions is they differ so much, I have a version like this one with external serial
https://m.aliexpress.com/s/item/3260341 ... siteDetail
I have another which is very similar but has usb micro connection , similar pin layout but female sockets and a differing pin order!
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