Author Topic: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1  (Read 8747 times)

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Offline mawyatt

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Re: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1
« Reply #50 on: October 09, 2024, 01:39:20 pm »

I apologize - I did not mean to be misleading! I actually earned my PhD 24 years ago, but in the humanities; I teach / serve as a Dean at Campbell University in central North Carolina. The university has a relatively new (~10 years old) School of Engineering, and I am finally getting a chance to fulfill a long-standing desire to sit in on a circuits class. Despite my professional focus on the humanities, I have been tinkering with designing / building circuits for 40+ years, and while I have generally succeeded in building something that works, I have always been painfully aware of how much I am "guessing" at design choices or at values to use (e.g., for a simple RC filter to quiet the bounce on a mechanical switch). Or as I often say, I have worked by trial and lots of error. :) Thus far, the class has been extremely enjoyable and has already filled in quite a few of the gaping holes in my knowledge. And this forum is adding to my knowledge as well!

That must be fun to sit in on an area you are interesting in learning about :-+

Electronics is fascinating, has been for us for almost 7 decades ;)

If you are interesting in better understanding of things try approaching from a fundamentals standpoint. Learn the basics in detail, then proceed with the application of such.

It lots of fun to sketch out a simple circuit on the back of an envelope, write a few equations, note some bias voltages/currents and waveforms. Then build on a protoboard and have it work 1st time without resorting to Google or LTspice, just pen, paper and trusty old HP calculator ;)

It's also fun being around young minds, you can spot the potential stars. When an Adjunct creating and teaching 1st advanced graduate classes in RFIC design we spotted those students and hired them (inside advantage)  :-+

Best
« Last Edit: October 09, 2024, 02:58:56 pm by mawyatt »
Curiosity killed the cat, also depleted my wallet!
~Wyatt Labs by Mike~
 

Offline awakephd

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Re: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1
« Reply #51 on: October 10, 2024, 03:36:01 pm »
That must be fun to sit in on an area you are interesting in learning about :-+
It has been very fun! With the professor's permission, I have been doing all of the work - homework, labs, quizzes, exams - it has been a great reminder to be on the student side of things. As dean, I oversee a graduate/professional program, and nearly all of our students are working significant hours, many with full-time jobs, families, and life responsibilities. I am planning to recommend to my faculty that they look for a class that they would sit in on, just to remember what it is like to be a student while juggling a full-time job.
If you are interesting in better understanding of things try approaching from a fundamentals standpoint. Learn the basics in detail, then proceed with the application of such.
Indeed! The course I am taking has proven to be "just right" in terms of what I already knew vs. what I need to learn. I have long been conversant with things such as Ohm's Law and the principles of how BJT and MOSFETs work. The class I am taking is more or less a "part two" class on circuits - the first class having introduced students to the things I have painfully learned (mostly) over many years. I was a bit concerned that my math skills would be too rusty; once upon a time I loved maths up through Calculus, but it has been many, many years since I have worked out a significant integral or derivative. So far, however, I am finding that what I have needed mathematically has come back quickly, and it has renewed my enjoyment of math. One thing that has been particularly interesting to observe is that often I know the practical implications / applications that the students know only in theory (and I may only now be learning the theory). For example, I've blown up more than my fair share of MOSFETs along the way, so when we discussed h-bridges and the problem of shoot-through, I could have testified!
 

Offline DaneLawTopic starter

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Re: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1
« Reply #52 on: October 10, 2024, 06:33:38 pm »
In regards to the zero/relative-feature on Fnirsi ST1.
On lower values fx 10mOhm from traces' it seems to relative that value on top, every time you hit it, a power cycle will remove that offset.
https://i.imgur.com/Muc3Zzr.mp4

While on bigger values fx 100mOhm it does seem to null it.
Tried to zero it on 100mOhm res (before the video starts), and the corresponding reading does cycles down around 0mΩ
https://i.imgur.com/ADMl0BR.mp4
« Last Edit: October 21, 2024, 02:45:41 pm by DaneLaw »
 


Offline tigrr

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Offline Paul T

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Re: LCR Tweezer Fnirsi ST1 vs. Zoyi MD1
« Reply #55 on: December 06, 2024, 11:03:16 am »
I now have both devices.  This past week I received a FNIRSI LCR-ST1 (v1.5 F/W).

I definitely like the ZOYI ZT-MD1 (v1.8 F/W) better. 

Here's 10 reasons why.

(1) The FNIRSI wheel operation (pushing) has a flaky response, like a worn-out switch.  Almost have to use my fingernail to push it.  Maybe it should be set higher.
(2) The refresh rate is similar, but the ZOYI settles in to a stable value a little better, especially on resistance.
(3) Resistance < 0.5 ohms is way more accurate on ZOYI.  Seems that the ZOYI is closer to a true 4-wire setup.  The ST1's REL feature is not very helpful.
(4) Inductance < 50uH is consistently low on the FNIRSI.  Same 10kHz frequency.  Can't REL it out.
(5) Schottky diodes measure 0.50 on the FNIRSI, could be confused for a silicon diode.
(6) The FNIRSI tips are more easily misaligned when squeezing.
(7) Bigger lithium cell on ZOYI.  Battery life is fine, but why is it half?
(8 ) The FNIRSI charges at 340 mA, which is C = 1.36, battery life might be affected?
(9) The price is about 25% more from FNIRSI.
(10) The ZOYI is easier to read the screen due to font and size, less busy.

On the other hand, the FNIRSI LCR-ST1 has some things going for it:
(1) More comprehensive data logs.
(2) The gold plating on the tips was more durable for me (doesn't flake off at the tip).
(3) The FNIRSI and the carry case look a little nicer and more colorful. 
(4) The screen protector is very clear and undamaged.  You can rip off the pull tab and leave it on.  The ZOYI screen protector is like thin food wrap.
(5) Only the ST1 has internal blade serrations, preventing radial lead components from rotating 90 degrees when squeezing onto the outside.

As a result, both sitting in front of me, I would definitely reach for the more accurate and easier-to-navigate ZOYI ZT-MD1 for most tests. 

Maybe I would be more likely to show off the FNIRSI to a friend.  That's about it.
« Last Edit: December 10, 2024, 11:26:35 am by Paul T »
Electronics always a core hobby. Sometimes I blog at KeepOnTesting.
 
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