Maziar,

I think what Keith is saying is that you don't need (or want) to
measure the resistance of a zero ohm resistor. The resistance of the
zero ohm jumper will be less than the resistance of the circuit board
trace it is replacing. If your circuit depends on the very low value
of the resistor, then it will also depend on the resistance of the
traces and you need to be concerned with those.

So if you want a jumper, use a zero ohm resistor. If you need a
resistance, use a resistor designed for use as a low resistance device.

Rick

--- In A...@yahoogroups.com, "Keith" wrote:
> --- In A...@yahoogroups.com, Maziar Tasbihi wrote:
> >
> > Hello,
> >
> > I think Mark is right in this case, and the 0R would be the zero ohm
> resistor, and I have a load of those. It is my mistake that I did not
> look closely.
> > But now to make it more difficult, what is the resistance of the
> zero ohm resistor? There must be some resistance right? I am asking
> this because I needed a 0.0x ohm resistor for another purpose and
> finally just used something else instead because could not find any.
> And, would anybody know how to measure the resistance on such a
> resister, I mean my ohm meter can only measure 1 ohm miniumum.
> >
> > Thank you and regards.
> > If you need need to measure a low resistance value, you need a
> micro-ohmmeter. To be accurate you would need kelvin leads that
> separate the voltage sense and drive current. This will keep the
> resistance of the test leads from interfering with your results.
> Short leads can also work such as comes with the low cost BK precision
> 875B LCR meter
>
(http://www.bkprecision.com/products/categories/sub_categories/models/?model=875B).
>
>
> In any case I would not measure the resistance but instead I would
> like at the data sheets and get the maximum resistance. For instance
> the KOA surface mount resistors are 0.05 ohm max
> (http://www.koaspeer.com/pdfs/res16.pdf) and the KOA thru hole
> (http://www.koaspeer.com/pdfs/res43.pdf) are as low as 0.01 ohm. If
> look around you could find lower resistances than these but you then
> need to worry about the resistance of the solder connections and
> traces. You probably want to look at the max current instead of the
> resistance. If you really care about the resistance you should get a
> current sense resistor (http://www.koaspeer.com/pdfs/res23.pdf) or a
> shunt (http://www.emproshunts.com).
>

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