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I'm assuming that copper traces on a PCB have negligible resistance. Is it possible to put a trace on a PCB that has some greater amount of resistance? The amount of resistance would not need to be precise per distance, but consistent along the length.

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    \$\begingroup\$ It is occasionally done with copper tracks if you want a low value resistor. A meander pattern is often used. If you google "PCB trace resistor" you will find several articles and calculators together with many images of how it's done. \$\endgroup\$ – Peter Jennings Sep 14 '19 at 23:51
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    \$\begingroup\$ If I remember correctly, standard 1oz copper foil has a sheet resistance of 0.288 miliOhm per square, at 25degC. There is a lot of variation over temperature, like around 50% initial value tolerance over commercial temperature range. Using thinner 0.5oz copper foil has about half the sheet resistance. Longer trace or narrower trace will have higher resistance (more squares). A trace that is 5 times as long as it is wide will have a resistance of about 0.001Ohm. \$\endgroup\$ – MarkU Sep 15 '19 at 0:03
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    \$\begingroup\$ @MarkU Wouldn't half-ounce foil be twice the resistance of one-ounce? \$\endgroup\$ – Hearth Sep 15 '19 at 0:13
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    \$\begingroup\$ "The amount of resistance would not need to be precise per distance, but consistent along the length." - why does it need to be 'consistent along the length', how long does it need to be, and what total resistance is required? \$\endgroup\$ – Bruce Abbott Sep 15 '19 at 0:31
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    \$\begingroup\$ @Heath oops, you’re right: thinner foil, thinner trace width, and longer trace length all increase resistance. Good catch. \$\endgroup\$ – MarkU Sep 15 '19 at 0:49
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printing with conductive inks can leave a resistive trace, but the process is fairly costly to set-up, and succeptible to variation is the the width of the gaps between traces and sensitive to flexing of the board, so it is only seen on large runs that have lots of low precision parts.

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