I've got a Uni-T UT622A on the way.
622A
100Hz, 120Hz, 1KHz, 10KHz 99999 Count
0.00pF~99.999mF
0.00μH~99.999H
ESR 0.0000Ω~999.99Ω
Uni-T do not specify accuracy on the various ranges It could be dreadful at 1pF and 1μH.
There are big differences in maximum ranges. For example the UT-622 series max out at 99.999H while the DE-5000 can go all the way to 2.0KH. That is a very big inductor.
If 100kHz is important, the ~$300 UT-622E adds a 100kHz test freq and DC resistance with .01milliOhm resolution.
This is a late reply to this older topic but given the scarcity of information on the UNI-T UT622 LCR-meter series in this forum I think that a reply to this old posting is warranted.
Andrew cites the display range for inductance as "0.00μH~99.999H" which I think comes from the
official datasheet -- which is still available (see link below).
However, the
user manual (page 41, also see link below) gives a much more believable range: "0.001uH - 9999.9H"
That would mean 10KH.
Why is that "much more believable"?
Because it has a) a more realistic looking lower ceiling of "0.001" instead of "0.00" uH
and b) the other display ranges look less like a cut & paste job in the manual (resistance only 10 MegOhms?).
Also consider, this is a 99,999 and not a 9,999 count device. Higher/Lower ceilings are expected (even if they aren't necessarily more accurate).
Finally, datasheets are usually getting produced much earlier than the manuals.
Therefore I conclude -- albeit without final proof -- that the manual has the correct values.
I wonder how many customers they lost thanks to the (still!) faulty datasheet?
And indeed: UNI-T doesn't provide an accuracy table. Neither in the datasheet, nor the manual or on their website.
What they offer, though, is a rather large section in the manual how they calculate the accuracy (pages 42 - 44).
The accuracy formula for L/C/R/Z/X/DCR measurements contains lots of stuff but the gist of it seems to be that you have to try to get the best parameters under the circumstance.
This accuracy will never get better than 0.1 % and it will likely get worse (= higher %), depending on the parameters (voltage level, speed) and more (impedance, temperature...).
It looks a bit like they tell us "use
friendly parameters and hope for the best!"
On a final note, the UT622-series consists of three models:
622A: max. 10 kHz, no DSR-measurement, alligator clip test leads with rubber plugs
622C: max. 100 kHz, no DSR-measurement, four-terminal kelvin test leads
622E: same as 622C but with DSR-measurement
Everything else should be the same, including accuracy, speed etc.
So if you want 100 kHz but don't need DSR you could get the 622C which is much cheaper than the 622E.
Both the datasheet and the manual can be downloaded here:
https://instruments.uni-trend.com/EU-EN/search?scode=all&name=ut622Product page (links to manual & datasheet don't work for me):
https://instruments.uni-trend.com/EU-EN/lcrmeters/ut622.htmlHTH