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FNIRSI LCR-ST1 (Inexpensive LCR Tweezers)
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indman:

--- Quote from: Kosmic on August 21, 2024, 09:37:12 pm ---Some measurements (all done at 1kHz):

  SR720MS8911LCR-ST12nF 0.1%C: 2.0004 D: 0.00025C: 1.99 D: 0.000C 2.012nF / D 0.0040 the difference in readings is D - 16 times!
 1uF 0.5%C: 1.0001 D: 0.00031C: 1.000 D: 0.001C: 1.002 D: 0.0002 the difference in readings is D + 1.5 times!
 500nF 0.5%C: 500.87 D: 0.00023C: 501.0 D: 0.000C: 503.4 D: 0.0040  the difference in readings is D - 17 times!
 125nF 0.5%C: 125.31 D: 0.00018C: 125.0 D: 0.000C: 126.1 D: 0.0032  the difference in readings is D - 17 times!
 5nF 0.5 %C: 5.0054 D: 0.00024C: 5.00 D: 0.000C: 5.022 D: 0.0027 the difference in readings is D - 11 times!
 160 pFC: 160.07 D: 0.00140C: 1.6 D: 0.001C: 164.0 D: 0.0002  the difference in readings is D + 7 times!

So overall I'm pretty satisfied. Measurement is fast, accuracy seem to be in specs, form factor is small and light and the screen is bright and easy to read.

--- End quote ---

If this toy is positioned as a bridge meter, it should at least somewhat fulfill this purpose.
Look at your table more closely - do you see what a huge difference there is in the secondary parameter D readings at 1kHz?!!! Why do you need such a resolution for this parameter of 4 digits after the dot, if he's grossly mistaken by the third digit? The MS8911 has a lower resolution of 3 digits and it more adequately shows a D value similar to the results in the SR720 instrument. ;)
I've already pointed out the incorrect D measuring on a similar ZOYI tweezers here
https://www.eevblog.com/forum/testgear/zoyi-zt-md1-new-lcr-tweezers/msg5604897/#msg5604897
I'll repeat my question here - If the secondary parameters Rs, D, Q can't be trusted, then they become a useless addition and can mislead you, right?
Aldo22:
What would you see as the advantages of these LCR tweezers (Zoyi, Fnirsi...) over a transistor tester (e.g. GM328A with SMD pad)?
Is it mainly about the handling?
indman:

--- Quote from: Aldo22 on August 22, 2024, 10:27:36 am ---Is it mainly about the handling?

--- End quote ---
No, it's mostly to do with the way these devices work!
Tweezers work with sine signal and at different frequencies, transistor tester works at 1st frequency and only with rectangular signal! ;)
Aldo22:

--- Quote from: indman on August 22, 2024, 10:53:47 am ---
--- Quote from: Aldo22 on August 22, 2024, 10:27:36 am ---Is it mainly about the handling?

--- End quote ---
No, it's mostly to do with the way these devices work!
Tweezers work with sine signal and at different frequencies, transistor tester works at 1st frequency and only with rectangular signal! ;)

--- End quote ---

Thank you. I guess so, but what does that mean in practice?
I assume that if the GM328A shows me 20pF, the tweezer will also show me 20pF etc.?
You say yourself that the secondary parameters can't be trusted. In-circuit measurements are apparently also questionable.
So what practical difference is there between these cheap devices?

As a beginner/hobbyist, I wonder whether such a device would be of any benefit to me.

indman:

--- Quote from: Aldo22 on August 22, 2024, 11:44:29 am ---I guess so, but what does that mean in practice?
I assume that if the GM328A shows me 20pF, the tweezer will also show me 20pF etc.?
You say yourself that the secondary parameters can't be trusted. In-circuit measurements are apparently also questionable.
So what practical difference is there between these cheap devices?

--- End quote ---
Despite my criticism, a tweezer or a device that works as a bridge meter will give you much more convenience and advantages than a transistor tester. Do not forget that this tweezer is positioned as an full-fledged LCR meter, the capabilities of the transistor tester are very limited in terms of measuring these values, as they are in fact only a bonus application to the abilities of this project. For example, can you reliably measure a 1pF capacitance on a tranzistor tester? Yes, Karl-Heinz has a great resonant method of such measurements, but it is only an exception to the rule. :)
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