Whether you are estimating on the spot or checking a result somebody else gave you, the pcb trace current calculator is the quickest way to get from ambient temperature, length, max. desired temperature rise, the trace is…, trace thickness, trace width and one way to trace temperature, power dissipation and cross section cm.
What Is the PCB Trace Current Calculator?
The pcb trace current calculator turns ambient temperature, length, max. desired temperature rise, the trace is..., trace thickness, trace width and one way into trace temperature, power dissipation and cross section cm.
It is a quick way to get from the numbers you have to the number you need, without setting up a spreadsheet or reaching for a formula.
How the PCB Trace Current Works
Each result follows from the ones before it, and the calculator shows every step, so a surprising answer can be traced back to the input that caused it.
Round your inputs to the precision you actually know, and keep more precision than that in the intermediate steps.
Getting a Result You Can Trust
Run the calculation twice with slightly different inputs. A sensible calculator moves its output in proportion; a wild change points to a unit or a decimal point problem in what you entered.
Write the inputs down next to the answer. It takes a moment and it is the difference between a number you can explain and one you cannot.
A Worked Example
Working through an example, with ambient temperature set to 10, length set to 5, max. desired temperature rise set to 2, the calculator returns cross section of 1,378, and trace temperature of 12, and maximum current of 6.14639. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out trace temperature?
Enter ambient temperature, length, max. desired temperature rise, the trace is..., trace thickness, trace width and one way. The calculator then works through the relationship and reports trace temperature, power dissipation and cross section cm.
What does the pcb trace current actually calculate?
It takes ambient temperature, length, max. desired temperature rise, the trace is..., trace thickness, trace width and one way and converts them into trace temperature, power dissipation and cross section cm using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter ambient temperature?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.