my first PCB has a trace measuring 0.1 Ohm resistance

[donbright]

(edited.too late to remove this.. so ill retype it so the replies dont look weird.)

i got a PCB made and thought a trace should have 0 ohms but it had 0.1 ohms,

i thought jumper wires and traces should be 0 ohms, after i wrote this i went back and measured everything... turns out my meter fluctuates between 0 and 0.1 ohms, on jumper wires, traces, everything. so basically i was going under wrong assumptions and too quick measurement. 

thanks

[voltsandjolts]

0.1 Ohms is fine, don't worry about it.

[wraper]

First of all how precise is your measurement? If it's only the last digit on your multimeter then this measurement is not precise. It could be a 0.01 Ohm of difference that makes such difference in reading. Also you need a 4 wire measurement to really trust such readings since contact resistance with probes could be dominating in such measurement. Secondly all depends on trace length, width and copper thickness. You can calculate expected trace resistance. https://www.allaboutcircuits.com/tools/trace-resistance-calculator/

[donbright]

thanks @wraper

i went back and measured as soon as i clicked 'post' and u are right, my old multi-meter fluctuates between 0 and 0.1,  especially if i leave it on a few seconds, and i was just assuming things are 0 ohms when they arent.

[mag_therm]

Some multimeters have a feature that can null your probe resistance, so the next measurements are more accurate.
On Extech meter here, short the probe tips and press "Rel" button.
Then the display will read 0.00 and the next resistance readings will be more accurate.
Works for L and C too, I think.

[wraper]

Then the display will read 0.00 and the next resistance readings will be more accurate.

It does not make readings any more accurate. It simply does subtraction job automatically, so you don't need to do subtraction yourself.

[pwlps]

For such low resistances you would need a 4-point measurement, but I don't know if your multimeter has a 4-point resistance probing capability.
https://en.wikipedia.org/wiki/Four-terminal_sensing
You might arrange it yourself though, using a current source and a voltmeter.

[WattsThat]

i got a PCB made and thought a trace should have 0 ohms but it had 0.1 ohms,

Well, you thought wrong. Practically speaking, nothing has a resistance of zero ohms. If we could make conductors with zero resistance, we wouldn’t need fuses.

With zero resistance, you could push a million amps through it and have no heat generated. The world would be a very different place if we could do that.

[Zero999]

Zero Ohm conductors do exist. They're known as superconductors, but only work at low temperatures and up to a certain current density.

Of course, for practical purposes, everything has a resistance. An ordinary multimeter, with a resolution of 0.1Ohm, is no good for measuring resistances this low.

[Doctorandus_P]

An LM317 can be used as a very simple and reasonably accurate current sink or source.

You feed in current at the input, pin, and put a resistor between the output and the adjust pins and use the asjust pin as your second terminal.

The reference voltage is around 1.25V, so with a 12.5Ohm resistor, you get a 100mA current source or sink, and by tweaking the resistor you can calibrate the current.

Then, with any simple Power supply (between 5 and 30V) which can deliver those 100mA you have a simple measurement adapter to do 4-wire measurements with your DMM by measuring the voltage over your PCB track.