Design a New Precision LCR Tweezers with Much Lower Cost(Video Attached)

[kripton2035]

this is not blue but for me it's a white oled display.
get a display model that exists in different colors, and tell us the display model
if anyone want another color, they can change it if needed.

[Zlotnik]

+1 for „everything but blue“
Not only used inflationary so now looks „sooo 2005“, but there’s an optics reason it just doesn’t work well for displays. Chromatic aberration of the eye leads to quite significant defocus for monochromatic blue light. It’s actually kinda interesting why we don’t usually notice it, here’s recent nature paper on the topic:
https://www.nature.com/articles/s41598-020-79911-w

Anyway, it’s best to use blue displays or indicators only when there’s a good reason, and stick to “boring” colours otherwise.

[Shannon]

I changed the light and the camera, and it looked very different. See the attachment for the new photos.

That looks normal. The numbers look contrasting and easy to read.
Don't pick on the little things.
In the photo I see slightly different starting capacitance on all the devices. Is it calibrated or is it still to be calibrated?

Thank you for your deep question.
To be honest, the moment I saw your question, I also started to think.
But I found the answer to the question right away.

You know that at the two ends of the tweezers tip, one end is the output of the excitation signal, and the other end is the input of the excitation signal.
The tip of one of the tweezers is close to the tip of the other tweezers, and a mutual coupling capacitance is formed between the two "metal plates".

As you can see, both tweezers have 10kHz excitation signals. This useful (Interference) signal is detected, and there is a strange unstable offset and noise.
And the other unusual phenomenon is “Insulated” desktops will also affect the measurement results

Use a video to illustrate this problem couldn’t be better.

[xwarp]

I wouldn't mind reviewing against a pair of SMT tweezers, a DER DE-5000, and a Beckman ESR meter.

[indman]

Del

[SilverSolder]

Use a video to illustrate this problem couldn’t be better.

Hm..Have you deliberately chosen a parallel circuit(Rp) on one tweezers and a series circuit(Rs) on the other tweezers?
Can you show a video of the calibration process? I've written you before that too much resolution and sensitivity is unnecessary for tweezers with a 2-wire connection.

The wires on a tweezer are very short...   so a 2 wire connection in a tweezer probably performs better than a desktop DMM with long leads?

[Shannon]

Use a video to illustrate this problem couldn’t be better.

Hm..Have you deliberately chosen a parallel circuit(Rp) on one tweezers and a series circuit(Rs) on the other tweezers?
Can you show a video of the calibration process? I've written you before that too much resolution and sensitivity is unnecessary for tweezers with a 2-wire connection.

Do you want to say that in the open circuit state, set the test mode of different tweezers, one is the capacitor and the resistor in series, and the other is the capacitor and the resistor in parallel? I am a little confused. What indicators do I want to see in this test?

As for the two-wire and four-wire and the corresponding accuracy, I can’t remember if I have an explanation,
but we did lead the four-wire to the tip of the tweezers, so the error comes from the contact impedance and the coupling between the tip of the tweezers?
For extreme cases, such as short-circuit or open-circuit conditions, these errors cannot be ignored, but for most cases, higher resolution and accuracy are more welcome.

[indman]

Del

[SilverSolder]

The wires on a tweezer are very short...   so a 2 wire connection in a tweezer probably performs better than a desktop DMM with long leads?

Yes, the tweezers have a short length, but for measurements of small capacitance, inductance and resistance even this makes a difference. Because it is still not a full 4-wire connection, even if the 4 conductors converge at the 1st point.
[...]

Since the layout of the "test leads" never changes much in a tweezer, maybe some of those effects can be calibrated out?

[Shannon]

I wouldn't mind reviewing against a pair of SMT tweezers, a DER DE-5000, and a Beckman ESR meter.

That would be very interesting.
we have the confidence to win the game

[Shannon]

Use a video to illustrate this problem couldn’t be better.

Hm..Have you deliberately chosen a parallel circuit(Rp) on one tweezers and a series circuit(Rs) on the other tweezers?
Can you show a video of the calibration process? I've written you before that too much resolution and sensitivity is unnecessary for tweezers with a 2-wire connection.

Shannon Tweezers Calibration Process.
Here is the video

[Shannon]

I just paid attention to the fact that usually in automatic mode, selecting the circuit and the absence of parts on the input terminals, the device itself switches to the parallel circuit, which is more suitable for measuring small capacitance. See how the initial capacity is set and the mode is set on the similar HB-14 tweezers.
[/quote]
I don't know if I understand is correct.

You are suggested that when DUT is a small capacitor, people will pay more attention to the characteristics of the parallel resistance, which represents leakage performance
and when DUT is a large capacitor, people will pay more attention to the ESR of the capacitor, which represents the effect of capacitive filtering.

Therefore, it is best to automatically switch between these two models, when the capacitance parameters are measured?

[indman]

Del

[KungFuJosh]

What's the status of these? I'd love to try them out.

Thanks,
Josh

[fkfaraz]

Its been months. still no update..

[SilverSolder]

It's an ambitious project... 

[Shannon]

Hey there, we are still here, and the good news is we have sent out some pieces for some friends.

And the KS project is coming, here is the KS PREVIEW link, and I cannot wait to share it with you.
https://www.kickstarter.com/projects/751050478/526869536?ref=c0jkaw&token=665a4d84

This link is "preview version", so if you have any comments, please let us know, we will still try the best to make it better.
Please ignore the time line and two "leather case" inside, we will modify them .

To be honest, we are all struggle in the boundary of BEST, but the time is limited, especially under the impact of the epidemic.

Add Discharge Cap Before Measurement! Attention! Video for your reference.

[SilverSolder]

[...] Discharge Cap Before Measurement! Attention! [...]

I will resist the temptation to ask you how you know! 

[thm_w]

Looks good.
What are the "precision calibration board" capacitors tolerance wise, roughly?

[Shannon]

Looks good.
What are the "precision calibration board" capacitors tolerance wise, roughly?

Precision Calibration Board capacitor tolerance is 5%.
High precision Capacitor is tooo expensive

The Resistors are 0.1% accurate, so these "components" cannot calibrate ST42, except short and open.

We designed simplified ST42 Calibration function, which only use Self Cal/Short Cal/Open Cal three mode to achieve 0.1% accuracy

[indman]

Del

[Shannon]

Hi there,

Recently, we continous send some ST42 to Early Birds.

And we are updating our website these days, shannontweezers.top will be closed these days.

For backup, If you need more information, please visit https://shannontweezers.github.io/ 

Thanks.

[Shannon]

The Resistors are 0.1% accurate

The specifications for your tweezers state the following:
Measure ranges:Resistors 0.05Ohm-9.9MOhm. Basic Accurate-0.1%.
What are the actual measurement errors for resistors at the edge of the range?
0.1% of 0.05Ohm is +- 0.00005Ohm. In the previous video you showed us the results when short the tweezer probes. The readings on the display are about 5-15 milliohms.
Why are you telling us fairy tales about the accuracy of 0.1% with a 2-wire measurement, even if it is a pseudo 4-wire one?

I'm not sure if this expression makes sense, we're using "basic accuracy" for the specification.

as you mentioned, the contact resistor error is about 10milliohms, so we cannot promise that the accuracy of the smallest gear is 0.1%.

A more scientific expression should be offset(code) + range error(percentage), but we'd better collect hundreds of ST42s to give instrumentation industry recognized spectification.

Obviously we haven't collected enough data right now, but even so, you can observe the excellent performance of the ST42 as well

[tautech]

Hi there,

Recently, we continous send some ST42 to Early Birds.

but not us. 

Unfortunate as we have a big tech show in a couple weeks and it would've great to exhibit your tweezers .......
https://www.emex.co.nz/visitor-information/about-emex/
Maybe you had forgotten about our interest in a # of units.

[Shannon]

Hi there,

Recently, we continous send some ST42 to Early Birds.

but not us. 

Unfortunate as we have a big tech show in a couple weeks and it would've great to exhibit your tweezers .......
https://www.emex.co.nz/visitor-information/about-emex/
Maybe you had forgotten about our interest in a # of units.

Hey tautech, we definitely not forget your interest.
You have supported this project at very very beginning stage, I will catch you soon.