EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: RAQU_PL on May 22, 2023, 11:08:51 am
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There is almost no information about these LCR meter on the forum so i would like to fill that gap.
Meter is too far off on my taste so adjustment will be required...
To cal meter four standards are necessary 24,9Ohm, 374 Ohm, 5.97k, 95.3k with known R, Q on frequencies :1k, 25k, 250khz, 500kHz, 1Mhz.
There is 7000-09 LCR METER CALIBRATION KIT available but considering the price DIY will be best option.
Last cal was in 2002 so it is not very drifty.
If anyone needs more pictures or better quality let me know.
As it is my first post let me know about my mistakes.
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more pics.
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And more pics.
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Surprised to see a pc104 based cpu board in this ....
the other stacked on top of it must some i/o interfaces going into the lcr side
clean layout tests points on the pcb etc ...
nice pick,
would it be better to have it calibrated instead of trying yourself ???
irk seen the cal kit price ridiculous
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Surprised to see a pc104 based cpu board in this ....
the other stacked on top of it must some i/o interfaces going into the lcr side
clean layout tests points on the pcb etc ...
nice pick,
would it be better to have it calibrated instead of trying yourself ???
irk seen the cal kit price ridiculous
Yes indeed, it is well built device.
I bought it recently from electro recycling company on local polish auction site .....
Talking about DIY cal i have in mind making standards from VISHAY thin film, low parasitics, stable resistors and sending it to cal.
DIY cal kit example:
https://youtu.be/rAsPUIbwM4Q?t=599
I very like the method of battery backup of user memory.
Three AAA baterries. No dallas or solderable batteries.
It was built with user and service in mind.
The biggest problem is lack of possibility to stop measurement in progress.
Example: When i do frequency sweep that requires few minutes to be performed and i want to change setting after pressing stop / menu i have to wait for sweep to end.
Or i am an imbecile and can't find another way.
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Looks like a nice unit! Thanks for sharing those pictures! The downside of (alkaline) AAA cells is leakage, so be sure to check and consider if the unit could take primary lithium cells in the same form factor (mind the slightly higher open terminal voltage).
Re the calibration kit the ideal scenario wow be to buy it and have someone measure the Q. Because even parasitic inductance and capacitance in the measurement setup could affect it. So Ideally you'd mount the resistor in an aluminum (eg. Pomona) box with BNC connectors and then characterize the assembled unit with another calibrated unit that you have access to, for example through friends, work or uni. I'm guessing this is the original cal kit came with BNC connectors? Or was it just leaded resistors?
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not being rude
you are going into a loop, the problem is: you need to build and characterize the builded jig(s) ..... BUT you need a calibrated equipment to do so
i think the best would be to: once calibrate your lcr, build the test jigs and caracterize them, and keep them in safety ...
my 2 cents
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Thanks for tearing it down. That is a lot more complex than I would have thought, certainly more than my gr1689. Interestingly enough , the reference resistors are the same, except your 24.9 is a custom EBG, while mine sticks with the S102.
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Looks like a nice unit! Thanks for sharing those pictures! The downside of (alkaline) AAA cells is leakage, so be sure to check and consider if the unit could take primary lithium cells in the same form factor (mind the slightly higher open terminal voltage).
Re the calibration kit the ideal scenario wow be to buy it and have someone measure the Q. Because even parasitic inductance and capacitance in the measurement setup could affect it. So Ideally you'd mount the resistor in an aluminum (eg. Pomona) box with BNC connectors and then characterize the assembled unit with another calibrated unit that you have access to, for example through friends, work or uni. I'm guessing this is the original cal kit came with BNC connectors? Or was it just leaded resistors?
Thank You for information about Li-ion AAA cells. To be honest i only know about Ni-MH existence in these form factor.
Yes, i want to replicate form factor. It comes with bnc in metal? box and Pelican case.
Unfortunately, I don't have anyone in souch places so commercial labs are only option.
not being rude
you are going into a loop, the problem is: you need to build and characterize the builded jig(s) ..... BUT you need a calibrated equipment to do so
i think the best would be to: once calibrate your lcr, build the test jigs and caracterize them, and keep them in safety ...
my 2 cents
Yes, I mostly agree but there is a catch.
Few months ago, wanted to calibrate and adjust my Solartron 7081 dmm and I've called two major acredited labs.
In first one I got answer that they do not adjust meters others than Gw-instek and the other only cal as well!
So even if I will send the meter i will have to adjust it myself..
After scrolling the IET labs cal kit i found information about calibration: "Calibration Accuracy: These resistors are compared with a precision of better than 40 ppm at DC . Measurement uncertainty of the nominal Q values are within 100 ppm at 1 kHz. All other R and Q values at other frequencies are mathematically calculated. All calibrations are made at 23°C ± 1°C."
On the top of pdf is stated that this is Z-foil bulk metal resistor.
I have few of vishay VFR resistors, selected 1k and did a sweep from 10Hz to 2 MHz. I hoped it is linear and DC only measurement will be enough to achieve datasheet accuracy.
Unfortunately, this is not the case or after measurement (kelvin clips – neither frequency response nor accuracy friendly setup) I don't know whether it is setup’s fault or resistors. I do not have currently anything better on hand.
Measurement was taken with 10x average, compensated leads. Sweep takes over 2 hours.
In attachment You can find sweep graph and original measurements.
Today I will order bnc, boxes and one z-foil resistor, I will post the results.
Thanks for tearing it down. That is a lot more complex than I would have thought, certainly more than my gr1689. Interestingly enough , the reference resistors are the same, except your 24.9 is a custom EBG, while mine sticks with the S102.
This is strange, according to datasheet, gr1689 is more accurate 0,02% instead of 0,05% for 7600.