Design a New Precision LCR Tweezers with Much Lower Cost 【Shannon Tweezers ST42】

[Shannon]

Shannon Tweezers Calibration Process

2021/12/30
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This video is to demonstrate the calibration process of Shannon Tweezers, which is easy to conduct through three steps.
you can observe how accurate and precise through this video.
Hope you like it.




Menu and ABS case Image Update

2021/10/05
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The unboxing Shannon Tweezers video is coming.
Forgive my poor English and video cut tech
Hope you like it.

This video content includes
1. the Container for the Tweezers
2. The ABS Case and Tips teardown
3. Accuracy Presentation
4. Hold Function and shortcut
5. Oscilloscope and Shannon Tweezers test each other

If you have any questions, please feel free to let me know.
Thanks for your suggestions and supports, we will be there.



2021/10/04
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About a year ago, a friend discussed an AC impedance measurement scheme with me, we think this scheme can meet most of the testing requirements. Then we started to cooperate to discuss the possibility of a more practical LCR tweezers.
Because of the impact of the epidemic, the progress of many works is surprisingly slow. After many experiments, we have realized its basic functions and prototype.

I share our experience here and welcome your comments. We will continue to optimize the design, If more electronic enthusiasts are interested, we will try to cooperate with more friends to make it into a product.

Compared with other LCR tweezers, this one uses a new high integrated scheme, which has higher accuracy and more stable test results. At present, it supports 100 / 120 / 1k / 10kHz, 0.5 and 1V excitation signal and impedance measurement, such as ESR,D,Q... The structure design of these LCR tweezers is much more stable, and the user experience is more like precision tweezers.



Cap Measurement Noise performance video
The screen measurement data update rate is 2 samples per second, which is much faster than the other high precision SMD testers, and there are about 100 samples record for 5pF cap measurement, 6fF peak to peak noise performance



Features as the attached image, continuous updating


These are the test results for precision resistors and caps at this moment:
The DUTs were Vishay S102 serial 1K 0.01%, 20K 0.01%, 100k 0.1%




The DUT is 5pf + 0.5pf @ 10kHz and 10nf 1% @ 1kHz MKP capacitors

[tautech]

Will it have an Auto mode ?
When measuring electrolytics ESR should be displayed.

What battery technology are you planning on using ?
Can you fit a tiny battery level bar meter on the display or will you just pop up a battery low warning ?

[S. Petrukhin]

When and at what price do you plan to sell?

[Shannon]

Will it have an Auto mode ?
When measuring electrolytics ESR should be displayed.

What battery technology are you planning on using ?
Can you fit a tiny battery level bar meter on the display or will you just pop up a battery low warning ?

Sure, it will have auto mode, which could distinguish the DUT type and recommend the appropriate frequency automatically
ESR  would be implemented with Cap measuring, and Inductor measurement would have the similar Rs function.

We are trying to make it a real LCR meter, support those measurement modes

We use a rechargeable Li-on Battery, the battery level would be displayed on the screen.

Actually, we are focusing on the display now, I don't think it will be long

Type-C Port has been used for battery charging as attached.

[tautech]

ESR  would be implemented with Cap measuring,

Not in Auto mode ?
My old ST3 tweezers can do ESR in Auto mode.

[Shannon]

When and at what price do you plan to sell?

At present, we think the price will be around $100 for mass production

We will try to launch it on Kickstarter in one month. If crowdfunding is successful, the delivery time is expected to be two months

[Shannon]

ESR  would be implemented with Cap measuring,

Not in Auto mode ?
My old ST3 tweezers can do ESR in Auto mode.

Thanks tautech, we will do that.
The logic would be Auto mode will switch to Cap or Inductor measuring mode, and the ESR value would be displayed at the same time when cap value is displayed

[floobydust]

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

[Shannon]

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

I can't agree with you anymore, the excitation signal is a key factor for the performance

We used a pure AC signal for R/L/C components.

10pF cap excitation waveform attached.

[tautech]

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

My 2007 ST3 reads a 10uF 0805 at 8.54uF ESR~100 mOhm at 10 KHz

[indman]

Del

[indman]

Del

[Shannon]

Sure, it will have auto mode, which could distinguish the DUT type and recommend the appropriate frequency automatically
ESR  would be implemented with Cap measuring, and Inductor measurement would have the similar Rs function.
We are trying to make it a real LCR meter, support those measurement modes

Real LCR meter should be able to determine, in addition to ESR, also very important secondary parameters such as quality factor "Q" and dielectric loss tangent "D".
Without it, any tweezers turn into a regular beautiful toy like DT71.

Thanks indman
The ESR, Q and D measurement function have been implemented, UI is under modifying, we will make the main parameter and secondary parameter display at the same time 

10nF SMD Cap ESR measurement attached.

[Shannon]

The DUT is 5pf + 0.5pf @ 10kHz and 10nf 1% @ 1kHz MKP capacitors

Can you show a video where this capacitor is measured at least 3 times in a row?
Are you sure this tweezers needs this resolution of 0.0001pF?

Hi there, you are right, the noise would exceed 0.0001pF, and so many digits for pF level cap is unnecessary, but sometimes the noise could less than 0.01% as the video attached. 
and the other way to get lower noise is by increasing the sampling time for averaging.

the basic accuracy we achieved is 0.1% now, so the last digit would be not displayed in the end.

[indman]

Del

[S. Petrukhin]

When and at what price do you plan to sell?

At present, we think the price will be around $100 for mass production
We will try to launch it on Kickstarter in one month. If crowdfunding is successful, the delivery time is expected to be two months

This is too expensive to replace the wires of a stationary LCR meter. 
You've seen that the pretty model DT71 is 2 times cheaper. I'm not talking about the price of simple tweezers UNI-T, Mastech and Holdpeak.

[Shannon]

When and at what price do you plan to sell?

At present, we think the price will be around $100 for mass production
We will try to launch it on Kickstarter in one month. If crowdfunding is successful, the delivery time is expected to be two months

This is too expensive to replace the wires of a stationary LCR meter. 
You've seen that the pretty model DT71 is 2 times cheaper. I'm not talking about the price of simple tweezers UNI-T, Mastech and Holdpeak.

I guess, you've seen that the pretty model ST5S/LCR Pro1 is 2 or 3 times expensive. 

Well, I don't want to talk much about those product's shortcomings, they are more like DMM, here is a test and analysis post, you can get more details.
https://www.eevblog.com/forum/testgear/lcr-tweezers-test-and-analysis/

Have you ever seen an LCR Tweezers that could achieve 0.01% noise performance at that speed?
And look at the test image, we used 0.01% 2ppm precision resistors for the DUT.

We will post more details about the performance and structure design, it used as real precision tweezers, very easy to hold 0402 SMD components.
It is much more convenient to use than a stationary LCR meter, it could support SMD(independent or soldered on PCB) and through-hole components at the same time.
We have great confidence in it, you'll want to have a try

[Shannon]

and the other way to get lower noise is by increasing the sampling time for averaging.
the basic accuracy we achieved is 0.1% now, so the last digit would be not displayed in the end.

I watched the video, thanks! Once again I was convinced that the resolution of 0.01pF is quite enough for a meter with a 2-wire connection. All other extra digits are noise or random number generator.

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

I can't agree with you anymore, the excitation signal is a key factor for the performance
We used a pure AC signal for R/L/C components.

I believe that floobydust is right in this question, so many serious tweezers allow you to select the voltage on the measurement pins from 0.1VRMS-1VRMS

yep, we will support the different excitation voltage as well

For the large capacitance measurement, it's a long story, I will try to unfold it at another time.

[Zlotnik]

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

I can't agree with you anymore, the excitation signal is a key factor for the performance
We used a pure AC signal for R/L/C components.

I believe that floobydust is right in this question, so many serious tweezers allow you to select the voltage on the measurement pins from 0.1VRMS-1VRMS

This!
Make the excitation voltage selectable, and include also voltages low enough to not turn on pn junctions. This helps with in-circuit component measurements.

Price wise, you'll have to be clear on your value proposition.

[Shannon]

How does it perform with MLCC?
Because the voltage coefficient of capacitance is quite bad with MLCC, the original Smart Tweezers did not read them correctly and needed firmware update.

Example 10uF 10V 0603 at 3V is -40% for only 6uF. If you use a single ramp (compared to AC) to measure capacitance, then the value will be incorrect.

I can't agree with you anymore, the excitation signal is a key factor for the performance
We used a pure AC signal for R/L/C components.

I believe that floobydust is right in this question, so many serious tweezers allow you to select the voltage on the measurement pins from 0.1VRMS-1VRMS

This!
Make the excitation voltage selectable, and include also voltages low enough to not turn on pn junctions. This helps with in-circuit component measurements.

Price wise, you'll have to be clear on your value proposition.

Thanks Zlotnik,

That's the other main point! we will support selectable excitation voltage for the different test cases, especially for the PCBA components and pin cap measurement.

[Shannon]

Here is the detailed features

[S. Petrukhin]

I guess, you've seen that the pretty model ST5S/LCR Pro1 is 2 or 3 times expensive. 

Well, I don't want to talk much about those product's shortcomings, they are more like DMM, here is a test and analysis post, you can get more details.

Have you ever seen an LCR Tweezers that could achieve 0.01% noise performance at that speed?
And look at the test image, we used 0.01% 2ppm precision resistors for the DUT.

We will post more details about the performance and structure design, it used as real precision tweezers, very easy to hold 0402 SMD components.
It is much more convenient to use than a stationary LCR meter, it could support SMD(independent or soldered on PCB) and through-hole components at the same time.
We have great confidence in it, you'll want to have a try

The DT71 looks much more elegant and comfortable, the ST5S is unsightly. To use these tools as high-precision seems to me unwise. You can easily calibrate a demo sample and lose accuracy in mass production. If you ensure accuracy in mass production, it will be good. But we don't know that yet. 

I didn't buy a DT71 for $50 and I won't buy yours for $100, it's expensive and more convenient for me to use a stationary device.

It is often very inconvenient to look at the tweezer readings when checking on the board due to the forced position of the tweezers. However, I suggest that you, as a friend function that will cure this deficiency: automatic locking readings. It works like this: if the measured value is stored for more than, for example, 2 seconds, issue a beep and record the readings so that you can turn the tweezers and look at the screen. Of course, the time and on/off of this function must be added to the settings. 

[tautech]

Shannon
Do allow for display flipping so to cater for both right and left hand users.
Don't change the form factor as it's proven to be very functional and robust.

It would seem from the # of digits displayed great accuracy can be obtained however for a device of this type it robs valuable display real estate that might be better used to show some other user setting or measurement parameter.

Will your tweezers allow for user firmware updates ?

[Shannon]

I guess, you've seen that the pretty model ST5S/LCR Pro1 is 2 or 3 times expensive. 

Well, I don't want to talk much about those product's shortcomings, they are more like DMM, here is a test and analysis post, you can get more details.

Have you ever seen an LCR Tweezers that could achieve 0.01% noise performance at that speed?
And look at the test image, we used 0.01% 2ppm precision resistors for the DUT.

We will post more details about the performance and structure design, it used as real precision tweezers, very easy to hold 0402 SMD components.
It is much more convenient to use than a stationary LCR meter, it could support SMD(independent or soldered on PCB) and through-hole components at the same time.
We have great confidence in it, you'll want to have a try

The DT71 looks much more elegant and comfortable, the ST5S is unsightly. To use these tools as high-precision seems to me unwise. You can easily calibrate a demo sample and lose accuracy in mass production. If you ensure accuracy in mass production, it will be good. But we don't know that yet. 

I didn't buy a DT71 for $50 and I won't buy yours for $100, it's expensive and more convenient for me to use a stationary device.

It is often very inconvenient to look at the tweezer readings when checking on the board due to the forced position of the tweezers. However, I suggest that you, as a friend function that will cure this deficiency: automatic locking readings. It works like this: if the measured value is stored for more than, for example, 2 seconds, issue a beep and record the readings so that you can turn the tweezers and look at the screen. Of course, the time and on/off of this function must be added to the settings. 

Elegance comes at some cost. I suggest you take a look at the comments on dt71 in this forum

Thanks for your advice.
We have built in Hold function as the feature table show.

We are very serious about mass production specification, so the basic accuracy we cannot figure out in this stage, even through the test result is very good, BUT we have confidence in that because we didn't spend much attention on those calibrations to achieve less than 0.1% as the image shows. We will try to follow the strict definition by using 3 Sigma for the worse case.

[Shannon]

Shannon
Do allow for display flipping so to cater for both right and left hand users.
Don't change the form factor as it's proven to be very functional and robust.

It would seem from the # of digits displayed great accuracy can be obtained however for a device of this type it robs valuable display real estate that might be better used to show some other user setting or measurement parameter.

Will your tweezers allow for user firmware updates ?

Hi tautech,
Thanks for your advice.
display flipping is a design goal for this LCR tweezers.

We will certainly support firmware updates, but the update method has not been decided yet.
I will update the feature list later