ITTSB.EU Blog Forum
Electrical Test and Measurement instruments => Bench-top multimeter => Topic started by: Kiriakos GR on May 26, 2026, 09:36:45 PM
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I was not aware so far of Fluke 8845A, Agilent 34401A performance limits at 100 Ohm range.
4W theorem of operation with Kelvin connection, this is well known.
Under the thought that Kelvin connection this is not limiting measurement range, what it does limiting measuring resolution this is the DMM it self.
In simple words, is it possible any DMM with a minimum of 100 Ohms range this acting as microscope? so us to measure down to milli Ohm resistors?
I did find some clues at one very old Group community, at year 2008, several 34401A owners, they were tested all sort of Kelvin clips and wire harness of that era.
And they witness or faced, some sort of disappointment.
100 Ohms range, this limiting low resistance measurements by allot, instrument floor noise and range limits, does not aloud you going lower than 20 Milli Ohm.
4 milli ohms plus some % of the reading, these are hardware limits of 34401A hardware as plain noise.
20 Milli Ohm resistance (DUT resistor) this is little more above noise of the DMM it self.
100 Milli Ohm resistance (DUT resistor) this is somewhat more easy to measure if you think characterizing resistance tolerance.
No one can do much when this class of instruments comes only with 100 Ohms range, this be blind measuring lower than 100 milli Ohm.
But there is something that you can do about savings.
You can stop wasting money and time, at Kelvin harness with golden dust over the clips.
Because in the end of the day, nothing can help getting more performance from these.
FLUKE 8846A this were born (designed) to offer 10 Ohms range.
This is capable measuring under the 100 milli Ohm resistances.
In my surprise I can dive down to 1 milli Ohm resistance. :)
But this is now the actual limit.
100% of 2026 bench-top DMM production, this comes with 100 Ohms as lower range.
The message from T&M brands, this is give us more money, if you need dedicated milli Ohms meter.
In conclusion, when you are truly aware of hardware limit's, only then you may make correct decisions about spending at test leads and Kelvin style harness.
Hobbyist , education , experiments, go for economy design of Kelvin large clips.
Go for the common type of 1$ USD per clip, and get few more than you actual needs.
Nothing lives for ever, plastics degrade and die after few years of time.
Watch out and boycott, all thieves selling over 3$ USD per clip.