# Zero ohm resistor tolerance?

This 0Ω resistor has a tolerance of ±1%.

Well it would only be +1% at best because you can't have a negative resistance* but still 1% of zero is still zero?

Shouldn't it be something like 0$\Omega$ + 0.001R?

*except in very special cases with certain devices but never over the full operating range.

• -1R, the answer to all our energy problems. – Mr. Hedgehog Oct 19 '10 at 21:34
• Next thing we know overunity.com will have a section on negative resistors. – Thomas O Oct 19 '10 at 21:39
• They already do. jlnlabs.online.fr/cnr/index.htm This, of course, originated from some idiot journalists framing an experiment as a "breakthrough in superconductors" because they don't understand electronics. You can't put a current through one branch of a circuit and measure a voltage across another branch and call it resistance. – endolith Oct 20 '10 at 1:50
• and it has a temperature coefficient! – DarenW Dec 11 '10 at 1:36
• @Thomas O: It might also be -1% because 0$\Omega$ * -0.01 is still 0$\Omega$ (not negative). – Curd Jan 21 '16 at 21:30

If you look at a "proper" data sheet (example: http://www.yageo.com/documents/recent/PYu-RC0603_51_RoHS_L_4.pdf) you'll usually find that the zero ohm resistor is defined separately using something like < 0.05R.

In this case, you're looking at a more or less automatically generated set of data which is probably more relevant to the other resistors in the range. Multicomp in this case refers to multiple sources so the parts could be coming from anywhere; the data in this case is fairly general and is most likely the lowest common denominator for a variety of alternative devices.

• Even for this "multicomp" part the datasheet seems to call out the tolerance for the zero ohm resistor seperately. It seems it's just the website that has the nonsensical tolerance. – Peter Green Dec 19 '16 at 22:49

Yeah, that doesn't make sense.

The resistance is only approximately zero; only a maximum (typically 10–50 mΩ) is specified. Thus, a fractional tolerance (as a percentage of the zero-ohm ideal value) would be infinite and is not specified.

• A fractional tolerance wouldn't be infinite though, it would be zero, and finite, right? – Thomas O Oct 19 '10 at 20:19
• if your in a situation where 10-50 mOhm matters, or comes even remotely close to mattering, don't use a 0 ohm resistor. I mean a 1 inch 10mil trace on 1oz copper results in roughly 50 mOhm resistance. – Mark Oct 20 '10 at 0:23
• @Thomas - not the first problem with the quality of the supplied information on Wikipedia. I'm not a fan. – stevenvh Jan 26 '12 at 17:09
• @ThomasO: Why? The percent error is divided by the accepted value, which in this case is 0. Anything divided by 0 is infinite. – endolith Jan 26 '12 at 17:37
• @stevenvh: You mean that you can't just blindly trust everything on it, and have to read critically, just like every other source of information in the universe? I'm horrified! – endolith Jan 26 '12 at 17:37

Apparently someone got carried away and thought that just because it looks like a resistor, it should have a tolerance like one.

Well, it's really just a resistor shaped piece of wire, so the only thing that would make much sense would be to spec 'not more than X amount of resistance', where X would presumably be a few milli-ohms.

If it was absolutely necessary to state it as a tolerance, it wouldn't be incorrect to say X/2 +/- 50%, but who has ever heard of a 50% tolerance part?

• You clearly have not had to purchase enough capacitors if you have not heard of 50% tolerance. Supercaps can be hilarious in their specs. – Kortuk Oct 20 '10 at 14:06
• -20% to +80% is often seen for super caps. – Thomas O Oct 20 '10 at 14:17
• i guess i should have been more specific, and said who's ever heard of a 50% resistor; caps are notoriously widely spec'd. – JustJeff Oct 20 '10 at 22:01