LCR Tweezer Fnirsi ST1 vs. Zoyi MD1 - Page 1
Forum section: electronics / testgear

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 18, 2024, 08:13:14 pm
content: Fnirsi's ST1 LCR tweezer and how it stacks up to Zoyi MD1 - pro & cons between them.They do differ more than I expected, even though the test fundamentals are the same. (AC 0.3v 0.6v & 100, 1k, 10k Hz)Will try to highlight some of the differences.Values on these two units.ZOYI MD1=0.6v AC (597.6mV)0.3v AC (298.9mV)100Hz = 100.4Hz1K = 1004Hz10k = 10.040Hz[FW1.7]Fnirsi ST1=0.6v AC = 604.9mV0.3v AC = 302.7mV100Hz = 100.8Hz1K = 1008Hz10k = 10.080Hz[FW1.5]* On the Fnirsi ST-1 you can toggle secondary parameters. [D, Q, Z or X] by pushing the jog-wheel, Im not familiar with that you can do that on the Zoyi MD1?..* ST-1 datalog your values by hitting HOLD-button to an excel sheet on its internal memory.* MD-1 does the same logging with HOLD (from fw1.7) but uses a txt-sheet.* ST-1 indicates in the manual that you (at least to an extent) can zero/relative your value with a short push on the turn-on button.* ST-1 has a significantly more pointy gold-plated tweezer tip than MD-1, same goes for the angled tips that come incl. with the bag-bundle, MD1 also comes with extragold plated tips, but looks like the same variant as the fitted ones.* The thicker tips on the MD1 are more firm, than the longer & sharp ones on ST-1.* ST-1 is fitted with 1 metal finger-screw at each side, and one secondary guide hole/connection point.* MD1 tweezer tip is fitted with two inserted screws at each side, and the resistance reading on Zoyi MD1 do seem more stable than my ST1-unit that tends to bounce,depending on pressure, & the connection points from tweezer tips to handle.* ST-1 has a magnetic back, so you can attach things to it or hang it away on a metal surface.. it comes with an included metal disk with adhesive.* ST-1 weighs 44g and MD-1 37g and a tad shorter-.* MD-1 is significantly more stable in its reading than Fnirsi ST1.* Would have preferred a 2-screw tipblade-fitting on Fnirsi ST1, as we see on MD1 and ST42 and most other LCR tweezers* You can adjust the screen brightness, buzzer volume, screen orientation, time-delay for auto-off, and both units rely on the common TypeC charging interface for theirinternal LIPO cell, while FW-update, is the same run-of-the-mill .bin file to root-folder.* Zoyi MD1 Modes: Auto, Res, Capacitor, Inductor, Diode, Continuity buzzer with a given Ω value.* Fnirsi ST1 Modes: Auto Res, Capacitor, Inductor, Diode/Continuity buzzer.Overall I like them, though also worth having in mind, I dont have any other LCR tweezers, so some of the fondness could be down to a honeymoon LCR tweezer phase.The MSRP on the Chinese market seems to be 138CNY (19.5$) and doesn't look to be any significant price difference between them in China, while on the western optimized reseller sites. the Fnirsi ST1 seems to be a tad more expensive, both use a 4wire kelvin measurement AC approach.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 18, 2024, 10:06:53 pm
content: You can adjust the screens update rate on the Fnirsi ST1, as the update-rate seems to be sensitive to the selected frequency, so way faster update-rate at fx 10.000Hz (3 to 5 times per second) than fx 100Hz selected (around 1 time per second) while 1K/1000Hz is around 2 to 3 times per second.This behavior ain't the case on Zoyi MD1, which stays around 1 update per second on all selected frequencies..Video example with 100Hz, 1k, and 10K Hz and screen update rate that changes with frequency..+ toggling through secondary parameters.https://i.imgur.com/mXXOhh0.mp4Zoyi MD1 [Atm latest firmware 1.7]FW 1.7 =https://zotektools.com/firmware-update-md1/FW 1.8https://zotektools.com/products/zoyi-zt-md1/Manual =https://drive.google.com/file/d/1uJsOOQG1xBg4W1QcAgkmIN8IeYh9oZYz/viewFnirsi ST1 [Atm latest firmware 1.5]FW =https://www.fnirsi.com/cdn/shop/files/LCR-ST1-V1.5.zipManual English:https://static.eleshop.nl/mage/media/downloads/LCR-ST1-Manual.pdfManual CN/Eng. =https://www.fnirsi.com/cdn/shop/files/LCR-ST1-Manual.pdf

author: skander36
author_rank: Frequent Contributor
timestamp: September 18, 2024, 10:20:30 pm
content: ST1 fw. is 1.5 and still can't test diodes. It show 0.65V in both both directions.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 18, 2024, 10:55:42 pm
content: I don't think I have tested either of them on diodes yet, It's kind of an uphill battle with 0.3v and 0.6v.

author: tautech
author_rank: Super Contributor
timestamp: September 19, 2024, 01:00:31 am
content: Quote from: DaneLaw on September 18, 2024, 10:55:42 pmJust how ?Any half decent diode test will display Vf regardless of value.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 19, 2024, 01:48:42 am
content: Quote from: tautech on September 19, 2024, 01:00:31 amAs emphasized, haven't tested diodes with either of these, so what it does and doesn't do in regards to diodes - and if its a half-decent diode-tester after a given criteria - its all up in the air.You could get one and find out - if these 19.5$ LCR tweezers are "half decent" diode-testers after your own criteria of half-decent....I somewhat doubt it... do recall an obs-notice in the manual about the use' when testing diodes. (*manuals posted above)I usually turn to other items when testing diodes, but that's another matter... these LCR tweezers ain't targeted lighting LEDs or a wide aspect of diodes.. with the power they operate with, you're poking at the knee region of many diodes with the ltd current.You also got a continuity buzzer., like most half-decent LCR SMD tweezers should have..// Here buddy...https://www.keepontesting.com/post/zoyi-zt-md1-bonus-reviewI found an article that tested numerous diodes with the Zoyi MD1, so you can read that feedback, and see if it's your "half-decent" diode tester.I haven't tested diodes with it, so can't help you, though, do have in mind, it's not the ST1 as Skander36 refers to, but the other MD1 model in this thread..The article does highlight limited current when dealing with certain diodes...

author: Aldo22
author_rank: Super Contributor
timestamp: September 19, 2024, 09:48:45 am
content: Quote from: tautech on September 19, 2024, 01:00:31 amI think it's somewhat useful for determining polarity in-circuit "while you're at it" and if Vf isn't too high (Zoyi MD1).For everything else I would use a transistor tester.I wouldn't use the word “decent” for this feature.

author: tautech
author_rank: Super Contributor
timestamp: September 19, 2024, 10:02:01 am
content: Quote from: Aldo22 on September 19, 2024, 09:48:45 amYeah well, just what do you need other than polarity and Vf ?

author: Aldo22
author_rank: Super Contributor
timestamp: September 19, 2024, 10:39:13 am
content: Quote from: tautech on September 19, 2024, 10:02:01 amIt's not really accurate and Zoyi is apparently not really proud of it either:Quote from: Zoyi MD-1 User ManualBut yes, in many cases it will show you the polarity.

author: Frex
author_rank: Regular Contributor
timestamp: September 19, 2024, 11:35:03 am
content: Hello,I own too the Finrsi LCR-ST1 and I don't understand the complain about the diode test.I have latest firmware (1.5) and the diode test work well, it display voltage dropand a picto on screen show the direction of the diode (no need to take care about polarity).Right, displayed Vf value are (much) higher than expected, but for checking purpose I think it's sufficient.And I like also, the continuity test mode allowing easy short circuit find (R<50Ohms).Very good value for money IMHO.Regards.Frex

author: awakephd
author_rank: Regular Contributor
timestamp: September 19, 2024, 03:01:29 pm
content: The Zoyi MD1 will display the diode direction (and voltage drop? I think? I didn't pay much attention to that, as I was only interested in polarity) for an ordinary silicon diode, but it cannot test an LED. Frankly, with only .6V, I am surprised it can get over the threshold for an ordinary diode!

author: skander36
author_rank: Frequent Contributor
timestamp: September 19, 2024, 03:13:13 pm
content: The complain come from the fact that diode function is behave like is not working. The voltage is the same in both directions!On Fw1.3 the minuscule diode icon on left is not changed at all. So with that behavior for someone used to check a diode with a DMM this function seem to not working.I have installed 1.5 fw and indeed now the icon is rotating to show the sense of diode. But the voltage is still the same in both directions. Is the same AC signal (0.6V AC) used to check the LCR components so maybe they should apply a separate voltage for diode.Anyway for his price this device is pretty good because they manage to read LCR values with reasonable precision in most of the cases.LE - In this video at 6:14 the diode test realized by one youtuber. -

author: awakephd
author_rank: Regular Contributor
timestamp: September 19, 2024, 07:29:02 pm
content: Since it gives you the polarity, it seems to make sense that it shows the same voltage either way - it is giving the voltage drop (perhaps not very accurately), and indicating the direction of that voltage drop with the icon on the left. Or at least, that is how I understood it - ?

author: Aldo22
author_rank: Super Contributor
timestamp: September 19, 2024, 07:53:44 pm
content: How do you interpret that?GM328A says 705mV, AN8008 says 621mV and ZT-MD1 says 520mV.The diode was a 1N4148. The datasheet says Vf=1V, if I read that correctly.Are they all off, or what does that mean?

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 19, 2024, 08:23:05 pm
content: Quote from: Aldo22 on September 19, 2024, 07:53:44 pm"Forward voltage: IF = 10 mA, VF 1V (max)"The datasheet says to expect 1V maximum Vf with If at 10mA. You're under that, and I'm assuming it's unknown what the test current level is.

author: Aldo22
author_rank: Super Contributor
timestamp: September 19, 2024, 09:41:15 pm
content: Quote from: KungFuJosh on September 19, 2024, 08:23:05 pmThat's right, thank you. I had forgotten about that.So:An8008: 1.4mA -> 620mVGM328A: 4.2mA -> 714mVZT-MD1: 0.058mA -> 520mVThis is somewhat consistent with thedata sheet.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 19, 2024, 10:03:55 pm
content: Quote from: Aldo22 on September 19, 2024, 09:41:15 pmThe first two look okay based on Figure 4, but the MD1 looks high looking at Figure 3. 60µA looks like it should be 475mV...but whether that's off because the MD1 isn't great, or because of ambient temperature is another question. Was it -25C while testing? 😉

author: Aldo22
author_rank: Super Contributor
timestamp: September 19, 2024, 10:35:41 pm
content: Quote from: KungFuJosh on September 19, 2024, 10:03:55 pmI don't know that. It could be that the hand warms it up.But maybe I measured it wrong.The MD1 uses sine waves to measure diodes.I'll have another look tomorrow.EDIT: If I measure the AC current (TRMS), I get 0.14mA. That looks better

author: Paul T
author_rank: Regular Contributor
timestamp: September 20, 2024, 02:00:53 am
content: I described the diode function (and other things) in my blog here:ZOYI ZT-MD1 Bonus Review

author: Aldo22
author_rank: Super Contributor
timestamp: September 20, 2024, 10:24:32 am
content: Quote from: Paul T on September 20, 2024, 02:00:53 amYes, I had already read it.Very nice review!And yes, I also didn't understand why Rs and Q are not logged.

author: Paul T
author_rank: Regular Contributor
timestamp: September 20, 2024, 09:04:53 pm
content: I suggested a firmware update contains Rs logging and beep on diode detection.I'm thinking I need both.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 21, 2024, 08:07:16 pm
content: Continuity buzzer.MD1 got a dedicated buzzer mode, while ST1 beeps in Diode-mode.MD1 do in fact also raise the screens update-rate with higher frequency-selected (at least in some modes)*Click the speaker-symbol for sound, the Zoyi MD1 is maxed out on its buzzer level, to give an indication of max volume..Zoyi MD1 - Quite a difference in reactiveness, between the Hz-modes.. Here with 10K vs 100Hz to elevate the difference in screen-responseFnirsi ST1 (*Btw can you toggle the secondary parameters Q,D,Z,X on the MD1, like exampled here with ST1?)

author: Phil1977
author_rank: Frequent Contributor
timestamp: September 24, 2024, 12:48:57 pm
content: I just have both tweezers of the thread title available for comparison.Beside being a very similar product in general, the Fnirsi ST1 is significantly more responsive. Especially in Auto-mode the ST1 may take 0.5s to show a reading after making contact with the DUT. The MD1 takes maybe 1s. It´s really not a big difference, but big enough to make a difference for me.PS: Just checked with a potentiometer and video camera: The ST1 has an update rate of ca. 2Hz, the MD1 ca. 1.2Hz. Both devices have been set to Auto, 1kHz, 0.6V. What´s impressive with both devices is that they both do not show any visible delay for range or measurement type switching. That´s so much better than most "smart" DMMs which usually take seconds to recognize if they are connected to a cap or resistor and then have to try different ranges.

author: Phil1977
author_rank: Frequent Contributor
timestamp: September 25, 2024, 07:28:21 am
content: I have both tweezers available up to next week. If someone has and idea for something interesting to compare then please tell me.In the dedicated Zoyi thread was mentioned that the ST1 uses a more classical AFE with two instrumentation amplifiers before a switch while the MD1 puts the switch first to save on the BOM. Maybe this explains why the MD1 seems to be slower.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: September 25, 2024, 08:17:12 am
content: I just recorded a review for the FNIRSI and found that I could not zero them, the manual states it can be done, but in my case is doesn't actually zero, but goes down to NEGATIVE mOhm's, from power up it does -38mOhm when shorted, if I put a 100mOhm resistor on it I get about 67mOhm... trying to zero gets WORSE, down to negative 66 or so, and then negative 102mOhm or so ! if I then put the 100mOhm on it, I get about 2mOhm !Tried all different things, no good.It's on V1.3, tried to install V1.5... firmware doesn't take, I get the disk on the computer, and have boot loader 0% on screen, but copying the firmware .bin over results in no change at all, nothing happens, again tried doing it different ways, no good, probably because I am on a Mac rather than a PC.UPDATE tried on a PC and got firmware updated, didn't fix the zeroing issue though, that is no different.

author: Paul T
author_rank: Regular Contributor
timestamp: September 25, 2024, 09:16:09 am
content: Hi Scott, Did you try calibration? I assume the FNIRSI has a similar menu item to the ZOYI where you can go in to zero out any offset by doing the 0 ohm cal.

author: Frex
author_rank: Regular Contributor
timestamp: September 25, 2024, 11:13:45 am
content: Quote from: TheDefpom on September 25, 2024, 08:17:12 amHello,I have experienced same issue.To solve this, I had need to calibrate it (I had seen the procedure on a linked video in another FNIRSI ST-1 thread)When it is in off state, you need to push the toggle knob at left and push power button at same time to go in such mode.Then you see the calibrate screen and you can select calibrate value between short, 1, 10, 100, 1k, 10k, 100k, 1M,10M and open.Of course you need precise resistor value of each.I hope that help.Regards.Frex

author: Paul T
author_rank: Regular Contributor
timestamp: September 25, 2024, 11:17:19 am
content: And if it’s out of cal because of experimenting with that part of the menu, you are supposed to be able to restore the factory setting using the reset feature in the menu.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 26, 2024, 08:39:15 pm
content: Quote from: Frex on September 25, 2024, 11:13:45 amThx for the info, about the hidden cal-menu that pops out with toggle-to-left (while a push-in activates the bootloader)Do you know if such a manual user-calibration takes precedence, or will its "menu/restore" flip ST1 back to scratch and remove a given user cal.?.Over the top. packaging Fnirsi are using when shipping these ST1, if such packaging are the norm.The product is already safely inside its own form-fitted hardcasing and with a promo-cardboard outside, - seems quite excessive to also put it inside a massive flamingo-temperature resistant box that elevates the footprint numerous times, but then again, better safe than sorry, as parcel across the globe can be harsh affaire..Looks like the battery is quite a bit bigger on Zoyi MD1 (400mAh) than ST1 (250mAh)

author: DCFluX
author_rank: Newbie
timestamp: September 27, 2024, 10:35:59 pm
content: I was looking to replace my original Smart Tweezers with something a bit newer so I figured I'd give the Fnirsi LCR-ST1 a try.So far a big draw back that I just discovered is the inductance scale. Lowest display reading is 0.0uH, and it does not have enough display resolution to be useful for parts in the nanohenry range which is really what I need it to do for RF work.I am impressed with the full color display but my second gripe is there is no way to flip the display, which I also need because I am left handed.I have to do some more testing but I just clipped on to two capacitors that were 39pF and one measured 51 and the other 59.I just tried some more capacitors and whoa, weird results for sure. So on my bin of 1, 2.2 and 4.7uF the readings on the different caps all look about in spec for the tolerance but on the 10uF parts they are reading anywhere between 6.8 and 7.5uF and I can take those same parts to another component tester and have them read around 9.85 to 10.2uF

author: Feuerbard
author_rank: Contributor
timestamp: September 28, 2024, 08:58:56 pm
content: New onehttps://www.banggood.com/ru/LCR-1S-Smart-Tweezers-LCR-Tester-100kHz-CNC-Metal-Case-High-Accuracy-Portable-1_47-inch-Color-Display-Intelligent-Auto-Range-Function-p-2022417.html?akmClientCountry=MD&cur_warehouse=CN&ID=6329370&rmmds=search

author: elantric
author_rank: Contributor
timestamp: September 28, 2024, 09:12:02 pm
content: SNAKOL SK-BD1https://www.aliexpress.com/item/1005007544688000.html

author: u37
author_rank: Newbie
timestamp: September 28, 2024, 11:59:02 pm
content: Feuerbard, What's interesting about it is not 100 kHz at all. Take a closer look atthe picture. Very few LCRs can measure in the presence of external voltage, in subj it will not work. Unfortunately, this is off-topic.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 29, 2024, 04:24:30 am
content: Quote from: DCFluX on September 27, 2024, 10:35:59 pmWhat component tester are you referring your results to? they can vary a lot in their approaches.. and "component-tester" is quite a loose term.. can vary from a 5-buck eBay tester to lab-rated ref-gear..What values are you testing 10uF with?Tested these two units MD1 & ST1 with 10uF on a cheap res/cap ref-board..Seems okay..and with 10uF and 1uf electrolytic caps-

author: elantric
author_rank: Contributor
timestamp: September 29, 2024, 04:44:37 am
content: https://youtu.be/Lt-Pi3PwyZsLt-Pi3PwyZs

author: DaneLaw
author_rank: Frequent Contributor
timestamp: September 29, 2024, 04:48:03 am
content: Quote from: u37 on September 28, 2024, 11:59:02 pmNo, pls share.It can be helpful to possible buyers to sort through some of the marketing 3D-rendered-imaging' if their specs can't hold water in practice.Looked online for QPLINK, and nothing stands out, I can't even find this S1-model on Aliexpress, by name-label or reversed image search..Could be its region-restricted or the fact that it is simply very early days, hopefully' the latter.

author: indman
author_rank: Super Contributor
timestamp: September 29, 2024, 07:48:31 am
content: Quote from: u37 on September 28, 2024, 11:59:02 pmI didn't quite understand what you wrote? How is the 100kHz measurement frequency related to the ability of the device to measure external voltage?The description of this tweezers claims to be able to measure external voltage from 0.1 to 16V :Voltage Range: ±0.1V to ±16VThe photo shows a LIPO 11.1V measurement in voltmeter mode. What's wrong with this regime according to you?

author: u37
author_rank: Newbie
timestamp: September 29, 2024, 08:31:05 am
content: Declaration.Discussion of another LCR is off-topic and please do not develop it, but the question is really useful for subj.Let's take both LCRs, they are built on a similar scheme (there are some differences, but it is not important for now). These schemes are very similar to the previously existing QPLCR. For example, let's take the scheme on 3s (pdf).I don't know what your level of training is, but I, for example, do not see any attempts to protect the device from external voltage (or a charged capacitor).If you apply voltage (on the same charged capacitor, or a DC source), it will connect between J1/2 and J3/4. Contacts J1-2 are shorted to each other, as are J3-4, these are Kelvin probes. So, external voltage is applied to two nodes in the LCR - to the output of the sine wave generator and to the voltage measurement input. The signal output is made on U1A and R9 with a virtual "0" on the "IV" of U5. If you apply an increased voltage, say 15 volts, then these 15 volts will go to R9 and then to the output of U1A. At the output of the microcircuit, the voltage cannot be greater than the V supply of the microcircuit +0.7 V due to the mandatory diode inside the microcircuit from the output to gnd and to Vdd. Due to the nominal value of R9, the current will be about 15/150 = 100 mA. This current will go through pin 8 to VddA of the processor. The processor will not be able to utilize 100 mA in its power supply and its voltage will begin to increase instantly. At 4 V, the microcircuit irreversibly burns out. If the polarity of the 15V application is different, then "-" voltage will go to R9 and negative current will go to the output of U1A. The built-in diode will send this current to gnd and if the diode withstands, then nothing will happen, but ... But, on the other hand, there will be "+" and it will go to the input-output of U5, resistors R1,2, microcircuits U3,4 and according to the same scenario, a current of 100 mA will cause this current to pass through the built-in diodes into the power supply of the microcircuits and, ultimately, into VddA. The processor will also burn out. This was about the "output", but there is also an "input" - this is U6 and its resistors R4,5. Inside the amplifier microcircuit there are also protective diodes and excess voltage will also be sent to the gnd and V power supply terminals of the microcircuit. R4,5 ratings = 100 Ohm (tears), the power supply of U6 is connected to VddA. The processor is finished again. In order to eliminate this obvious drawback, it is necessary not to (!) let the increased voltage to the input of the microcircuits. Moreover, the main problem is not with the ground, but with the "power supply" - draining excess power into the "power supply" is IMPOSSIBLE, in principle, impossible! And this is a big problem. If you just install a "USB interference suppressor", your processor will burn out even faster. The solution is not so simple, but you have to think a lot, because a simple zener diode has a very large capacity (didn't know? look at the documentation) and extremely disgusting voltage stabilization for 3-4 volts. At the same time, it is necessary to utilize currents of the order of 100 mA. In addition to general protection, it is also necessary to take into account the thermal power - supplying high voltage will cause a large current, as a result, a huge power will be released in a small box and it will burn out, literally burn out. To suppress the long-term passage of current, it is necessary to install "capacitors" in the measuring circuits of sufficient size and good quality. Ceramic capacitors change their value when the voltage changes (except for NPO), so you need film and/or electrolytic ones. This will not fit into the subj case.Apparently, QPLINK has these problems solved from the start. This means that it is guaranteed to be protected from charged capacitors up to the permissible operating voltage of the device (I don’t know, but 20 volts for sure). What does such a device give? Firstly, a more reliable and stable input. It is unlikely that anyone in their right mind will shove capacitors charged from a 230 V network, they are not even worth touching, and the device is immune to low-voltage charging. The second is measuring the ESR of rechargeable batteries and disposable batteries. It is needed to reject old/dead cans and in general, to understand what you bought - a battery or a bucket of sand. At one time, I made an RLC with exactly this function, measuring under voltage. And you know, it came in handy many times. And check the acid batteries (not to mention lithium cans) and look at the banal batteries - their ESR increases linearly as they discharge. The function is really useful.Of course, all that has been said applies to QPLINK only under the heading "if" - I have not seen this deviceand judge only by those products that I developed myself. ))

author: indman
author_rank: Super Contributor
timestamp: September 29, 2024, 09:25:08 am
content: Quote from: u37 on September 29, 2024, 08:31:05 amThank you for your very detailed reply, everything is clear to me from your explanation. Discussing the capabilities of tweezers is not beyond the scope of this thread, don't worry.Quote from: u37 on September 29, 2024, 08:31:05 amApparently this problem has been solved by the developer of the tweezers. One thing that is not very clear to me is that the tweezers show another voltage V at the same time as the LIPO - V: 3.332V? The Z:50.9mОhm reading on the right side of the display is probably the impedance of this battery at 1kHz?

author: u37
author_rank: Newbie
timestamp: September 29, 2024, 09:40:31 am
content: Quote from: indman on September 29, 2024, 09:25:08 amI don't know what it is. In fact, it should work as a classic impedance meter, but it doesn't have such a parameter. It doesn't look like the voltage of its own battery.QuoteNote that the value is approximately correct. ))

author: indman
author_rank: Super Contributor
timestamp: September 29, 2024, 11:05:20 am
content: Quote from: u37 on September 29, 2024, 09:40:31 amYes, that value does look real.Here is another interesting novelty from Chinese friends, which can operate at a frequency of 100kHz, and which can be used as a smart tweezers.https://www.banggood.com/LCR-P1-Pro-Smart-LCR-SMD-ESR-Tester-Precise-Measurements-Capacitance-Inductance-Resistance-1200mAh-Battery-1_54-inch-Color-Screen-Portable-Testing-Tool-for-Continuity-p-2021059.html?rmmds=detail-left-hotproducts&cur_warehouse=CN&ID=49510&trace_id=845b1727546126217But I don't think such a shaped instrument would be as convenient to work with as tweezers.

author: DCFluX
author_rank: Newbie
timestamp: September 29, 2024, 06:51:07 pm
content: These are 10uF ceramic capacitors that I sourced from Mouser.

author: Paul T
author_rank: Regular Contributor
timestamp: September 29, 2024, 06:55:07 pm
content: @DCFluX 100 Hz would be best when above 1uF, looks like yours is set to 1kHz. Please recheck at 100 and see if you get the same improvement.Here's some easy-to-remember rules of thumb. Once you get the general measurement at 1kHz, switch to the best frequency for better accuracy if needed.For capacitors10kHz forpF1kHz fornF100Hz forμFFor inductors10kHz forμH1kHz formH100 Hz forHI don't know of any meters that adjust the frequency for you automatically. Most good meters work the same as these tweezers. If you get a full-sized LCR bridge, you'll also need to learn whether series or parallel method should be used for your device or circuit.Meters with 100kHz can be more accurate at low pF or nH measurements.

author: Paul T
author_rank: Regular Contributor
timestamp: September 29, 2024, 07:21:44 pm
content: In my experience, high-value dipped MLCC tend to produce the greatest capacitance value variation from device to device. Not sure why. Unless I need low leakage around 10uF, I usually choose a polarized cap. Ceramic caps tend to be negatively impacted by DC bias, polarized caps require DC bias.Here's my comparative measurements with a LCR meter, changing only frequency. Transistor testers tend to be off by about 20% in my experience.

author: mawyatt
author_rank: Super Contributor
timestamp: September 30, 2024, 12:03:53 am
content: The basic issue with Tweezers, Handhelds and Component Testers is the limited amount of DUT test voltage and current available. This is where the more expensive Bench Lab Grade LCR Meters come in, they have the ability to support higher DUT test voltage and currents, as well as higher frequencies to evaluate the DUT.If one considers a low Z component with 10 milli-Ω impedance @ frequency, a handheld or tweezer that can deliver say 10mA RMS (14mA peak) produces only 100uV RMS across the DUT. This is a small and difficult voltage level to measure accurately. Whereas a bench LCR Meter can deliver over 100mA RMS to the DUT and thus produce a higher measurement voltage which yields a better result, and can do so at higher frequencies well beyond what handhelds and tweezers can support.Similar situation for high Z components, a handheld or tweezer can only deliver a small DUT excitation voltage and thus the measured DUT current is very low and difficult to measure accurately. If DUT is a small capacitance (high Z) then increasing the frequency can help however most handhelds and tweezers have a limited frequency range. Again a Lab Grade Bench LCR Meter can supply a higher DUT excitation voltage at a higher frequency for better characterization of high Z components.If one wishes to study the effects of various signal levels and/or bias levels on the DUT, then Bench LCR meters are the likely choice as handheld and tweezers have limited, or no abilities within these areas.These are a few reasons the Lab Grade Bench LCR Meters cost moreIf one is considering acquiring high fidelity DUT component measurements, it's a good idea to understand the limitations of various potential use instruments, which is a valid concept for any measurements in generalBest

author: awakephd
author_rank: Regular Contributor
timestamp: October 08, 2024, 12:45:38 pm
content: Quote from: Paul T on September 29, 2024, 06:55:07 pmPaul, thank you for this. I had not really understood the significance of the 100 - 1K - 10K settings on my recently acquired Zoyi MD1 ... and meanwhile I was getting some readings on various 10μF capacitors that seemed way too low. Checked again with the frequency at 100, and now getting readings much closer to the Keysight in the university lab. It seems so obvious, now that you have pointed it out, that readings for inductors and capacitors are frequency-dependent, but I sure missed that at first.Just to be sure I'm not missing something else ... I'm guessing that readings for a resistor should not care about the frequency. Right? Or have I missed something else ... ?

author: Paul T
author_rank: Regular Contributor
timestamp: October 08, 2024, 01:02:51 pm
content: It’s true, a pure resistor shouldn’t matter. However real resistors have inductance and capacitance. Especially wire wound. I use 1k for all resistors because the owners manual for my ztmd1 recommends best accuracy overall.

author: mawyatt
author_rank: Super Contributor
timestamp: October 08, 2024, 01:47:02 pm
content: Yes resistors are also frequency dependent and measurements should take this into account. They are also test level dependent as self heating can cause measurement issues (think TC).Vishay and Caddock Resistors are the usual types folks look too for precision and stability. For capacitors the C0G/NP0 ceramic types are good choices, also Polystyrene and Mica but these are more difficult to find.Getting highly repeatable results is difficult as everything from the usual ambient temperature and RH needs to be considered, but also the test signal level and type, DC Bias, test fixture, instrument measurement method, electrical environment & proximity and so on, influences results.One also needs a thorough understanding of how the measurement instrument operates and computes the displayed parameters if expecting highly repeatable and accurate results.As an example, a recent brief discussion concerning very high "Q" components and why the effective series loss element (Rs) was inconsistent in measurements, even displaying negative values!! These measurements were conducted on Lab Grade Bench LCR Meters. An analysis of the measurement method and parameter computation reveals an impedance magnitude and phase result from which the loss element Rs is computed. A high "Q" component will have an impedance phase approaching +-90 degrees from which the computation of element loss Rs is extremely sensitive to small angle variations, and can even produce the wrong sign!!BTW we just received the MD1 and quite impressed considered the costAnyway, these type measurements are well beyond what tweezers are intended for, but good for a user to understand.@ awakephd Note you are working on your PhD, congratsWhat's your research area and university?Best

author: DaneLaw
author_rank: Frequent Contributor
timestamp: October 08, 2024, 11:09:18 pm
content: Quote from: TheDefpom on September 25, 2024, 08:17:12 amIm not sure about the purpose of the "zeroing" that the manual explains..On my unit (FW1.5) it almost looked like its adding a +10mOhm offset everytime...so from reading around 3mOhm. and hold it together and push 5 times, it went up in the +50mOhm.though one thing Im not fund of on the ST1 is the 1x screw fitting.. you need to clean the contact-surfaces and then screw it down, with more torque than you usually would do with a fingerscrew to get consistent reading, but in general the MD1 seems to perform better with low mOhm readings-.

author: awakephd
author_rank: Regular Contributor
timestamp: October 09, 2024, 01:09:33 pm
content: Quote from: mawyatt on October 08, 2024, 01:47:02 pmI 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!

author: mawyatt
author_rank: Super Contributor
timestamp: October 09, 2024, 01:39:20 pm
content: Quote from: awakephd on October 09, 2024, 01:09:33 pmThat must be fun to sit in on an area you are interesting in learning aboutElectronics is fascinating, has been for us for almost 7 decadesIf 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 calculatorIt'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

author: awakephd
author_rank: Regular Contributor
timestamp: October 10, 2024, 03:36:01 pm
content: Quote from: mawyatt on October 09, 2024, 01:39:20 pmIt 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.Quote from: mawyatt on October 09, 2024, 01:39:20 pmIndeed! 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!

author: DaneLaw
author_rank: Frequent Contributor
timestamp: October 10, 2024, 06:33:38 pm
content: 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.Lookslike its adding the value.?https://i.imgur.com/i7YdCIs.mp4While 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 0mΩhttps://i.imgur.com/X6kHfFM.mp4

author: elantric
author_rank: Contributor
timestamp: October 21, 2024, 07:37:44 am
content: Quote from: Feuerbard on September 28, 2024, 08:58:56 pmQPLink LCR TWEEZERShttps://www.eevblog.com/forum/testgear/qplink-lcr-1s-smart-tweezer-(100hz-120hz-1khz-10khz-100khz)-50$/

author: tigrr
author_rank: Contributor
timestamp: November 29, 2024, 01:34:08 pm
content: Quote from: elantric on October 21, 2024, 07:37:44 amQPLCR User Manual- PDF, 1.58 Mbhttps://mega.nz/file/I5UABC6C#jVBlZjjKRdjQ-qyR2wumsVWKOKlYn0bU0DAoV51bvQk

author: Paul T
author_rank: Regular Contributor
timestamp: December 06, 2024, 11:03:16 am
content: 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.

author: Propretor
author_rank: Regular Contributor
timestamp: April 30, 2025, 05:34:53 pm
content: Even with firmware 1.6 in diode test mode, the reading on the screen must be divided by 1.41 to find out the true value of the diode voltage!

author: Paul T
author_rank: Regular Contributor
timestamp: April 30, 2025, 05:38:21 pm
content: Quote from: Propretor on April 30, 2025, 05:34:53 pmPlease provide a real case that leads you to this conclusion

author: Propretor
author_rank: Regular Contributor
timestamp: April 30, 2025, 05:52:10 pm
content: Quote from: Paul T on April 30, 2025, 05:38:21 pmYou can take any diode or Schottky diode, determine the voltage drop with a quality DC instrument, and then make similar measurements with the FNIRSI LCR-ST1. Divide the value that the FNIRSI LCR-ST1 shows by 1.41 and you get a value that is very close to the real value measured by a normal instrument. The explanation for this effect is very simple - the FNIRSI LCR-ST1 has no DC operation mode, and the developers forgot to divide the reading by 1.41 (SQR2). The actual, effective or RMS value of a harmonic signal is 1.41 (SQR2) times smaller than its amplitude. It's simpleThe difference will only be due to the accuracy of the measurement and the different amount of current flowing.

author: Paul T
author_rank: Regular Contributor
timestamp: April 30, 2025, 06:02:41 pm
content: Quote from: Propretor on April 30, 2025, 05:52:10 pmThank your for the theory on this. Since I have not encountered this error, could you show a real case? Personally I have noticed the diode function lacks accuracy, but all the readings were lower not higher.

author: jackobo
author_rank: Contributor
timestamp: May 09, 2025, 02:55:53 pm
content: Lads, in the end of the day, which one to get to have some play Fnirsi or Zoyi? )) the price nowadays +- virtually the same.

author: Paul T
author_rank: Regular Contributor
timestamp: May 09, 2025, 02:58:46 pm
content: I still feel the same as my detailed post several posts above.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: May 09, 2025, 04:10:03 pm
content: I also lean on MD1 it's a tad more stable but the tips is also not as pointy as ST1.Some things that ST1 got that the MD1 doesn't are selective secondary parameters.On the ST1, you can push in the toggle switch with a long push, and jump between the secondary values on a given reading, Q, Z, X, D (from +20shttps://tinyurl.com/mty2ye5k)The back is also magnetic on the ST1.. Easy to hang on anything metal (there is a small metal sticker-sheet incl. to hang it at any given place of choice).Got 3 of these budget LCR Kelvin AC tweezers.*QP-LINK 1S, *Zoyi MD1 and *Fnirsi ST1 "side by side" to give an idea of the size.QP 1S is quite a bit more expensive, and it shows in the alu build & design. It's more than double in price at $48 delivered (incl. 25% EUVAT/DK), but it also got more features... like a 0.1 V test mode, which can be quite useful for keeping semiconductor junctions off, avoiding latch-up, or damaging fragile ICs, while also reducing core saturation in small inductors and preventing inaccurate or false readings in nonlinear or sensitive components, like ceramic capacitors or high-impedance parts.It’s also worth noting that the QP LCR 1S has a 100 kHz measurement mode that, alongside 0.1V, can help highlight parasitic effects & frequency-dependent characteristics, which could be useful in real-world high-speed or analog designs.. QP-1S also got a 120 Hz mode, which neither MD1 nor ST1 has.That can be handy for checking parts used in full-wave rectified 60 Hz power supplies, like electrolytic capacitors and other power components, since it reflects real-world conditions like AC ripple & line frequency, it can help you get more accurate readings of capacitance and ESR..Especially in power, audio, and low-frequency magnetic circuits.QP-LCR LINK1S will also will do/measure DC voltage which I personally find handy to have in a small LCR tweezer, up to around a max of 16V* (if I recall correctly*) and it support higher tolerances like 10.000 count across the full range and it got an accelerometer that will flip the display according to your orientation, or you can user-select in the menu, but it could be that QP LCR 1S is out of production here in 2025, as very few listings last time I checked and prices were significant higher, so perhaps down to "old stock".// QP LCR1S not being produced anymore, so possible fw upgrades is more or less out with the bathwater, even though it got built-in menus for fw upgrades.Zoyi MD1 got the biggest gap of the three tweezers (highlighted below)QP LINK 1S - Zoyi MD1 - Fnirsi ST1

author: jackobo
author_rank: Contributor
timestamp: May 10, 2025, 05:29:59 pm
content: dont need them two Fnirsi and Zoyi MD1 or even 3 including QP. Just ordered ZT-DQ02. In addition to it having a hard choice between Fnirsi and MD1 tweezers, to play with. Should I better flip the coin?

author: DaneLaw
author_rank: Frequent Contributor
timestamp: May 11, 2025, 05:45:23 pm
content: Quote from: jackobo on May 10, 2025, 05:29:59 pmA tad conflicting, as in if you don't need an LCR tweezer, then don't get it.Wait for your Zoyi DQ02 and be familiar with that, and see if it will saturate your needs.

author: jebem
author_rank: Regular Contributor
timestamp: June 14, 2025, 03:47:52 pm
content: After reading several threads here, I have ordered two new LCR meters from ZOYI to join my humble cheap PROSTER BM4070 LCR Meter.So they are theZT-DQ02handheld model and theZT-MD1tweezer model.Although I would like to have a few more of these tweezer models like theFnirsi ST1, not to mention theAneng gn702or the3S QPL LCR Tweezer.All of them are in my AliExpress's Cart for further consideration.But concerning the models in discussion here:Using the published pictures and videos, it can be seen that the ZOYI ZT-MD1 circuit uses SD03 TVS diodes, one per input leg of the tweezers.They are marked as 03W in the diode package, and most probably are supplied by Leiditech.Being protection devices, the SD03 TVS diodes will conduct when the applied voltage is above 3.3V. Below that value they will exhibit very low leakage current in the nA region.While the usage of TVS diodes is a standard choice as a protection against electrostatic or surge voltage, usually two of these diodes are use in parallel.Here in the MD1 only one diode is used. This looks to be a less than optimal solution.What do you think?

author: jebem
author_rank: Regular Contributor
timestamp: June 14, 2025, 04:15:58 pm
content: Quote from: jackobo on May 10, 2025, 05:29:59 pmGet both the handheld and the tweezer models.The ZT-DQ02 handheld model gives better results and features, but is not supplied with tweezer probes for SMD testing. These need to be acquired elsewhere and I believe they are expensive if quality is required.The ZT-MD1 is much more convenient in use for SMD PCBs, no attached cables, having enough precision for regular work.So both have a place in the workbench.Also it is convenient to have more than one meter of any kind, to compare readings when in doubt or when one fails to work.

author: donwulff
author_rank: Contributor
timestamp: June 18, 2025, 11:24:51 pm
content: Noticing a pattern where a thread starts about some FNIRSI product, then it becomes recommendations for other brands instead, haha. Anyway, did the stupid thing with my LCR-ST1 and after measuring PSU main cap with multimeter and finding it flat, used the LCR-ST1 to measure the parameters... oops, that wasn't flat at all, just solder oxidization!Basically, this is one good reason to look for the cheapest instruments, if you ever suspect something like this could happen for you, even (or especially) if you do have more expensive instruments where it matters. Anyway, I immediately ordered new LCR-ST1, ANENG GN702 (Which looks identical to the "Zoyi MD1" in this thread) and even FNIRSI LCR-P1, which hasn't arrived yet, though based on the thread on it they can't even get the diode direction right? First impressions are that ANENG doesn't auto-identify diodes, and when you manually select diode-range, it's appears showing fixed 0.5V forward drop, which the manual seems to be hinting at with "The product's diode forward voltage measurement value is for reference comparison only, with measurement range of Vf 0.1V~0.6V. Values beyond this range will display "OL." For higher measurement requirements,select a more professional diode measurement instrument." (Emphasis mine).ESR measurements are also highly differing between the FNIRSI and ANENG on the 100Hz and 10KHz ranges. On the other hand, the ANENG has resistance calibration, if you have 1 to 10M ohm precision resistors at powers of ten... Due to the frequency dependency, I don't think that'll be useful. I might make a closer comparison if I have time, but FNIRSI feels like the clear winner here despite the slightly higher price of ANENG.Back on the topic of the FNIRSI capacitor-mishap; the the GS8632-MR OpAmp in the input stage visually blew up, the PGA112AIDGSR Zerø-Drift Programmable Gain Amplifier and ARTERY AT32F403ACGU7 MCU shorted internally. Since they're all relatively cheap components, I wanted to see if I can still revive it... however, FNIRSI only providers that drag & drop BIN update, and it turns out the ARTERY chip is read-protected checking on the replacement I bought. And no, it doesn't unlock when putting it into firmware update mode, already checked. I had a genuine problem trying to upgrade the firmware (It got stuck in firmware upgrade mode without the USB port enumerating), so I shot FNIRSI's info email address a question if I could have the full flash image to program with SWD (Worth a shot!) but they didn't respond at all.The firmware upgrade worked after the battery ran flat and it reset, though the new replacement chip doesn't have the bootloader. So does anybody have a full firmware image, or knowledge if the upgrade BIN image could be used somehow by its own?