LCR tweezers 100 kHz.

[mawyatt]

A good tweezers in the nanohenry range should react to a piece of copper wire. Such measurements were made with a piece of copper wire 0.65 mm, information is in the article from LCR Reader. I also made such measurements with a piece of copper wire 0.65 mm: 5 mm, 2.5 mm, 1.25 mm.

Those values don't agree with what is predicted by Grover's formula.

https://www.allaboutcircuits.com/tools/wire-self-inductance-calculator/

Even the wire resistance doesn't agree.

https://www.omnicalculator.com/physics/wire-resistance

Best,

[indman]

And it is even worse if they come up with different fantasies, attributing them to the topic starter.

It is the creation of fantasies, unsupported by serious evidence, that you are engaged in your topics on the forum

[indman]

We have both the Tonghui TH2830 LCR Meter and the TH26009B Tweezers and decided to run a quick test of SMD inductors @ 100KHz like the article. We did the Open Short Cal with the Tweezers a few times, even cleaned the blades with IPA, but can't get a repeatable Short reading within at least +-0.5nH as often as we tried. This uncertainty also reflected sometimes even higher in various SMD Inductor measurements in the 10nH to 500nH range shown with various SMD sizes starting at 0201 like shown below. If we change the our hand pressure, move hands around, or change tweezer orientation we can get readings of just about anything we want around the inductor value
This type behavior is exactly why we invested in various SMD Fixtures for SMD devices, some OEM, some modified and some custom, where we needed accurate and repeatable results

Thank you for the test, this once again proves that measuring such small quantities with tweezers is difficult and it is very difficult to get stable results, even with such high-quality instruments and devices as yours.

[mawyatt]

Just for fun we took a 2mm dia 5mm long Copper wire for measurement. This calculates as 1.74nH (Grover) and 0.0267 milli-Ω.

First was using the TH2830 LCR Meter and TH26009B Tweezers @ 100KHz, we couldn't get any type of stable readings and the results wandered from 10~13nH and 0.05~0.5Ω based upon hand pressure, orientation, and repeated DUT engagements.

Then we used the SMD Fixture as shown with the TH2830 LCR Meter, here the results were much more stable and much closer to the computed values but still some slight uncertainty. Note the test current and DUT voltage.

If the DUT were flat we could use our custom Split-Kelvin Fixture for even better results, which was specifically developed for these low Z measurements.

We just can't see how any type of tweezers, even dedicated LCR Meter quality types like the TH26009B can achieve accurate repeatable results at impedance extremes. We've tried over the years to achieve this without success and why we developed the custom LCR Meter Fixtures and modified SMD Fixtures to improve measurement results.

Anyway, guess our skills, techniques and equipment aren't up to par with those articles and those folks here, that can achieve these remarkable results with Tweezers at impedance extremes

Best

[indman]

Just for fun we took a 2mm dia 5mm long Copper wire for measurement. This calculates as 1.74nH (Grover) and 0.0267 milli-Ω.
First was using the TH2830 LCR Meter and TH26009B Tweezers @ 100KHz, we couldn't get any type of stable readings and the results wandered from 10~13nH and 0.05~0.5Ω based upon hand pressure, orientation, and repeated DUT engagements.

All correct and your results match my experience with such measurements.
Like the author of this topic, I can take 100 photos showing the result of 1 randomly matched measurement. But this does not mean that such measurements with tweezers will be correct and reliable. You just have to realize this and keep it in mind in your work.

[mawyatt]

BTW one can do a "sanity check" without any reference standards or such. Simply do a Zero Ohm Short Calibration (Tweezer Blades together), then measure the inductance of the Short with repeated engaging and disengaging (opening and closing) the Tweezers. That reveals the uncertainty in a Short, and likely anything else you measure will have more uncertainty.

Best

[mawyatt]

There was discussion about measurement ranges over here:
https://www.eevblog.com/forum/testgear/upgrade-from-a-der-de-5000-lcr-meter/

These are graphs that show the range limits of measurement with the Tonghui TH2830 and Hioki IM3536 Lab Grade Bench LCR Meters. Note the limits on Impedance, Inductance and Capacitance measurements. The IM3536 achieves lower Inductance limits by means of a larger available DUT test current (and higher frequency range) of 100mA RMS vs the TH2830 33mA RMS. Please note these graphs assume a proper Calibration, Measurement Technique and Fixture for a given DUT.

Hopefully this will illustrate the realistic limitations of DUT measurements for various types of LCR  instruments, with ranges over 10 decades for the TH2830 and 15 decades for the IM3536

Please note the error in the TH2830 Graph, the upper right corner should be 10fF not 10pF as shown, we illustrated this in RED as a note.

Best

[indman]

These are graphs that show the range limits of measurement with the Tonghui TH2830 and Hioki IM3536 Lab Grade Bench LCR Meters. Note the limits on Impedance, Inductance and Capacitance measurements.

Your expensive meters are inferior in measurement limit to this simple and cheap L meter for $2-3
The photo and design are not mine, just look at the small inductances it measures!?

[iet]

Tweezers 100 kHz QPLink LCR 1S, reply 2.
The main features are similar to LCR ST1. There are some differences.
Frequency 100 kHz.
Measurement voltage: 0.1 V
Voltage Range: ±0.1 V to ±16 V
Battery Capacity: 500 mAh
Intelligent Auto-Range Function
Watched the video. I liked the good stability of the numbers, the speed of measurements.
It is difficult to assess the quality of the tips of these tweezers yet.
Instead of the value of 0.6 V of the measurement voltage, it is better to make 1 V.
In the range of resistance measurements, do I need to correct 1 Ohm?
https://www.bilibili.com/video/BV14usaeWE1g/?spm_id_from=333.337.search-card.all.click

[mawyatt]

These are graphs that show the range limits of measurement with the Tonghui TH2830 and Hioki IM3536 Lab Grade Bench LCR Meters. Note the limits on Impedance, Inductance and Capacitance measurements.

Your expensive meters are inferior in measurement limit to this simple and cheap L meter for $2-3
The photo and design are not mine, just look at the small inductances it measures!?

Yes, those are far superior instruments and measurements

Best

[iet]

Measuring the ESR of capacitors.
I will make measurements at a frequency of 100 kHz with different tweezers. My attention will be focused on capacitors with low ESR. These are solid polymer capacitors, polymer SP Cap, tantalum and electrolytic low ESR.
For this purpose, a new tweezers measuring at a frequency of 100 kHz was designed. Basic information is here.
https://www.eevblog.com/forum/projects/esr-meter-with-extended-scale/
The tweezers are completely autonomous and allow you to install a 50 uA microammeter on it. A powerful 1900 mA battery and a charger are installed. The tips are made of polished brass. The tweezers have a universal power supply: from a battery and an external power supply and are switched on by a microswitch.
The scale is 0-100 mOhms.
The scale was calibrated with SMD resistors.
I made a test board.
Measuring SMD resistors.

[iet]

Measuring SMD resistors.

[iet]

Measuring the ESR of capacitors.
I made a test board.
Solid polymer capacitors.

[tautech]

Measuring the ESR of capacitors.
I made a test board.
Solid polymer capacitors.

https://www.eevblog.com/forum/testgear/lcr-cal-test-pcb/

[indman]

Measuring the ESR of capacitors.

You have already been repeatedly hinted in other topics - this circuit does not measure ESR, it measures the total resistance (impedance) - Z!!!

[iet]

tautech
Nice pcb.
Solid polymer capacitors.

[tautech]

tautech
Nice pcb.

Josh has some for sale:
https://www.eevblog.com/forum/buysellwanted/fs-lcr-cal-test-pcb-v5-(bare-pcbs-only)/

[iet]

tautech
Thanks for the link.
SP-Cap polymer capacitors.

[iet]

I would like to dwell in more detail on the ESR measurement of the SP-Cap polymer capacitor of the GY Super low ESR 820 uF-2 V series.
According to the datasheet, the max. ESR is 3 mOhms. If you look at the ESR/Impedance dependence curve from the frequency from the datasheet, the actual ESR is slightly less than 2 mOhms.
Two tweezers showed a value of 2 mOhms at a frequency of 100 kHz, which is very cool.
https://api.pim.na.industrial.panasonic.com/file_stream/main/fileversion/8713

[iet]

 In-circuit ESR measurement of the SP-Cap 220 uF capacitor.

[iet]

I made new tips for the LCR P ro1 Plus tweezers. The same 1mm polished brass plate is used. The thickness of the tips for the Pro1 is 0.6mm. The tips are now more rigid and require less effort when measuring.

[ranchero]

From time to time I'm fixing broken car remotes. No available schematics of course, the only way to find out values - to have another key of same model and measure its components. Most important ranges - below 200nH and below 10pf (there are many components with such values in car fobs). Often they are in 0402 size which doesn't help either. So good LCR-meter with 100kHz range and stable readings is a must.
I have DE-5000 and relatively expensive Chinese handheld tester (around $200 if I remember). They both produce comparable quite stable results with some tricks. Small values can't be tested in-circuit . Both units came with tweezers attachment, Chinese - with Kelvin clamps. However, for tiny components with tiny values the only good way to get stable readings - soldering them to small test board and insert board directly in meter, or (in case of DE-5000) - use TL-21 adapter (with very short 5cm cables and alligator clips). As I found - after proper calibration this works extremely well, I'm able to measure 1-2 pf capacitors with acceptable accuracy (even though stability of the measurement is more important for me).
I'd love to have LCR tweezers, it would make measurements (at least bigger values) much more convenient, component and display within sight. But at $350 (LCR Pro1)...times are tough. Maybe someday. Cheap ones - I have feeling that they would be just waste of money.

[mawyatt]

Here's something we did, modified a TL-21 with BNC cables to allow DE-5000 use with standard LCR Meter Fixtures like the SMD Fixture shown. Good for small SMD values and no need to solder SMD component to a test board!!

Edit: Here's a quick measurement of a precision 1pF C0G 0805 capacitor @ 100KHz, ref value (1.0104pF @ 100KHz) from Hioki IM3536 Lab LCR Meter. No tweaking the images, numbers, just a normal Open and Short DE-5000 with fixture attached by modified TL-21, then measurement.

Best

[ranchero]

Something as simple as this works PERFECTLY. Just need to solder component to PCB. But I found that old components (desoldered from other key for example), nearly impossible to measure correctly unless it's soldered anyway.

[iet]

From time to time I'm fixing broken car remotes. No available schematics of course, the only way to find out values - to have another key of same model and measure its components. Most important ranges - below 200nH and below 10pf (there are many components with such values in car fobs). Often they are in 0402 size which doesn't help either. So good LCR-meter with 100kHz range and stable readings is a must.

You don't need to buy tweezers with a measurement frequency of 100 kHz. If the resolution of 0.1 uH and 0.1 pF is enough, then tweezers with a measurement frequency of 10 kHz-ST1 will do just fine. As a cheaper alternative to Pro1-LCR 1S. It has 100 kHz.