My Review
I purchased this LCR meter for my personal use, and partnered up with Darren to give you a more in-depth perspective of the meter's capabilities. My device is not the same as his.
Here's what the device looks like when and turned on for the first time and also hooked to 5V USB-C charging:
What is it? The ZT-MD1 is an LCR meter, shrunk to a tweezer format. It isn't the usual tweezer-sized multimeter. It's a specialty tool specifically designed to characterize capacitors, inductors, and resistors with quality factors. It uses an AC signal for all measurements. Continuity was added, along with rectifier diode checking.
What it not? This device is not your typical SMD multimeter tweezers. No voltage is supported. No LEDs or zener diodes are measured. Your typical DMM tweezers are mostly working in the DC realm.
The ZT-MD1 has one very important mission, be a LCR "bridge" meter for reactive components.
What you get
The device comes with a semi-rigid zippered carrying case, charge/data cable, and small manual. Inside the case, the foam insert holds the device securely and the net holds the accessories. Online you get firmware updates with any enhancements and quality improvements that are issued after the sale. The device has selectable EN and CN languages.
I chose the option to include an extra set of tips. They are a flat stamping, shaped as pictured, with two tapped holes for installation. These extra metal blades were loose in the package, so I am glad they provide a screen cover on the device screen (removed before pictures). Fortunately, no damage occurred.
Look and Feel
The display is color OLED technology, which is perfectly visible at all angles. The font is bold and the information is uncluttered. My "old" eyes have no problem reading close or at a distance without any aberration. I never had problems distinguishing between similar digits such as 5 and 6. The brightness is level adjustable should you want to increase battery life or reduce potential burn-in of the emitter pixels. Alternately, you could change the auto-off timer from default 15 minutes to 5 minutes. Going the other way, you could go to 120 minutes or disable this timer completely.
The device has a rechargeable lithium ion cell inside with red charging, blue finished LED. An icon on the screen tracks your charge level, I never saw it go down much.
The device is small, lightweight, easy to hold and squeeze. The tips are pointed, nearly parallel, and plated with gold over nickel. They have a polished bevel at the very tip to make them more narrow. When you use the tweezers to test, they close inward to a very acute angle, tips touching first and the rest with a small gap. This worked fine for me, others might want them pointed more inward for better in-circuit maneuvering. The tips stay well aligned through a squeeze.
Although I'm showing the meter while charging, it is to be used while not charging.
Firmware
My unit arrived with v1.5 software installed. The next day after receipt, ZOYI released v1.6, improving speed of the high resistance readings. Then in a few more days they released v1.7, improving low resistance response, adding data export, and correcting an English spelling mistake. The link to the firmware is currently https://zotektools.com/firmware-update-md1/
I did not find any disadvantages of upgrading firmware. The process was easy, smooth, and nothing about the functions was diminished. They provide a YouTube video of how it is done and the link is in the comments. No re-calibration was needed afterwards. I found the measurements were the same, perhaps slightly better for high resistance.
Data Export Feature
Version 1.7 was the one that added Data Export capabilities. During upgrade, your PC asks if you want to format the device. Responding "yes" adds a partition on the device which is a reservoir for the data. Afterwards, your unit works like a 256 KB USB drive when device is on and plugged into a PC. Note: Do not activate the firmware USB boot feature to access export data - instead just turn on the device to measure screen an plug it into a computer. This process is shown during the second half of their YouTube video on how-to-upgrade.
Once the storage area is activated, every time you press "HOLD" the data will be appended to the "record.txt" file. You can start a new file by renaming the original text file or moving it off the USB drive, only when connected to a PC. At the end of this review, I will post a picture of what the text file looks like.
Automatic or Manual modes
By default, the ZT-MD1 will automatically select the proper mode in most cases. It will detect whether the component is considered capacitive, inductive, or resistive. Perfect when you have an unmarked part you are unsure of. If you are working at extremes of the range of the meter, or you want the tester to focus on one of these properties, you can sequence through R, C, and L modes. After these, you can access the diode test or continuity test features before the loop goes back to Auto.
For instance, I found if I connect a alligator lead in the auto mode, it will switch to "L" and report a few tenths of a microhenry. Instead, perhaps I wanted to measure the resistance of the wire instead. I could click the mode button until "R' is displayed before my measurement to force the unit to do what I want.
Interface
On the top are the only three buttons. They are intuitive and easy to press with the left hand while measuring with your right, resting on the curved space between finger and thumb. The screen orientation can be flipped in the menu, but of course the buttons stay where they are. I'm not going to go into all the instructions how to use, I'll just say it's a pleasant experience.
Understanding Voltage and Frequency
First, consider what a LCR meter does. It sends an AC wave at a certain voltage and frequency to the tips and measures how the component you attached shifts the waveform. For this reason, do not use the tweezers while charging, or near sources of electrical noise (LED lights, fans, etc). Unwanted EMF is likely to superimpose noise on the AC wave.
Amplitude
In the device screen, the unit displays 0.6V by default. This is used for all of your out-of-circuit measurements of components. You have the option to change this to 0.3V. You would do this for in-circuit testing, so that diode junctions nearby are not "turned on". This improves the chance that the "active" part of the circuit is less likely to affect your measurement of "passive" components.
Frequency
The frequency defaults to 1 kHz, which is middle of the range. This assures you will get some sort of reading when you first attach, and likely improves the chance of a good auto-detection.
Once you determine the type of component and it's general value from the 1 kHz setting, you can switch the frequency for a more accurate reading:
For capacitors
10kHz for pF (high frequency, low Farad caps)
1kHz for nF (many non-polarized caps)
100Hz for μF (generally electrolytics or tantalums)
Total range I found this device will measure: 10 pF - 22 mF
For inductors
10kHz for μH, (high frequency, low Henry inductors)
1kHz for mH, (common inductors)
100 Hz for H. (not very common)
Total range I found this device will measure: 0.1 μh - 60 H.
As I mentioned, an LCR meter measures how the device-under-test changes the AC signal that is sent to it. The frequency response needs to be a reasonable order of magnitude for it to do it's calculations accurately.
Using the wrong frequency is analogous to trying to measure 5 drops of water in a measuring cup, where the frequency setting is like the size of the cup. The device may try it's best, but is not going to register a very accurate reading unless you use the right size cup. This applies to not only the primary value, but also the secondary measures Rs and D.
For Resistors
I use 1kHz for everything because the chart in the owners manual promises best accuracy across the range in that column. Note that wire-wound resistors may measure incorrectly on this device. The manual shows 10 kHz is not appropriate for higher resistance.
Total range I found this device will measure in the main display: 0.5 mΩ - 10 MΩ
Equivalent Series Resistance Bonus
The Rs value at the bottom of the screen will display a reading for resistors that are over 10 MΩ. For instance, I could measure a 20 MΩ resistor at the bottom of the screen as 20.3 MΩ while the top showed "OL". However, the accuracy is not within a guaranteed range.
Diodes
Once you switch to the "▬►▌▬" mode, a typical silicon or Schottky diode will be recognized. The voltage drop and direction of the anode/cathode will be indicated on the screen with another diode symbol aligned to the test arms. If the diode is outside 0.1V to 0.6V, such as an LED or Zener, the display will show "OL". The voltage of the signal the device produces isn't intended for these types of diodes. Evidently this is because they wanted to keep the device lightweight and feature a long battery life. Changing the frequency didn't make any difference to the readings I did.
Also, because the test current is very low, your diode will be operating in the "knee" region of it's turning on. Therefore, the voltage is always going to be somewhat incorrect. I found a Schottky diode which measures 0.19 V on other devices measures 0.37 V on the ZT-MD1. Also, a silicon diode that often measures 0.60 V will measure 0.52 V on these tweezers. This explains why the manual says these values are for "reference comparison only" and they further recommend a more "professional" piece of test equipment for measuring diodes.
Continuity
Works responsively, but isn't particularly loud even at it's maximum setting. Might be handy for some circuit tracing where you can't see the inner layers of the PCB. It's a welcome feature that works smoothly. The manual advises to ignore any shown values.
Accuracy Assessment Graph for main value
I put this together to demonstrate how the ZT-MD1 measurements compare to my reference components. The baseline is average measurements across various devices I own or have access to. This isn't a perfect evaluation, but readily predicts the meter is able to conform to all it's specifications.
Secondary measure accuracy compared to LCR meter "D" and "Rs"
For capacitance, the phase angle of all my non-polar capacitors was so close to -90 that the D value was extremely small. My full-sized ESR meter and the tweezers disagreed entirely, but they were both trying to interpret a very small ESR value, that is when compared to the relatively large capacitance reactance. Any differences aren't due to any deficiencies in either meter, only in my selection of very good capacitors. Please don't get hung up on D values for non-polar capacitors, it's not worth worrying about.
For polarized electrolytics and tantalums, the D value was more meaningful and very consistent, although not always exactly the same. Bottom line, I can trust the ESR and quality factor these tweezers provide in the display for polarized capacitors.
For inductance, I found all the Rs and D values very close to the ESR my full-sized LCR meter reported. This is an East Tester ET431, by the way. Based on the results, I fully trust these tweezers for "L".
For resistance, the D value should be ignored because any phase angle is calculations of stray capacitance or inductance. During measurement, the Rs is essentially the same as resistance in the main screen. Everything below 1MΩ was super accurate, above 1MΩ measurements are good.
There is the ability to calibrate the resistance only. For a full cal, must have a thorough set of precision standard SMD resistors 1Ω, 10Ω, 100Ω, 1KΩ, 10KΩ, 100KΩ, 1MΩ, 10MΩ. Many won't have all these, so enjoy the supplier's very accurate factory calibration.
I didn't try calibrating, but I did check out the menu. It appears you can do one or all of the series; also open and short. Evidently you can erase what you did: The manual states, "To return to factory calibration data, perform a factory reset."
In summary, this LCR meter has a very wide range of accuracy, almost as good as my full-sized LCR meter. Less bells and whistles, but certainly capable and user friendly.
Downsides? There isn't a convenient way to test components with wide lead spacing. Other devices have a "d" shape tip that enables attaching standard test leads on the holes. To enable wide spacing, I used a short alligator clip, however it kept sliding off the smooth gold finish. I was careful to note any inductance or capacitance this loop of wire created. Unfortunately, there is no REL feature to zero out any additional RLC you impose on the circuit with an extension wire.
Maybe they could have made screen rotation automatic with a tilt sensor. Or added a feature to automatically lock in and hold a measurement once determined.
I would prefer a dedicated electrolytic test mode with a DC bias voltage so that some of the wave sent to it doesn't go negative. Not sure why they didn't implement this, perhaps they felt your test will be short enough that the device won't be damaged by the negative portion of the AC signal this device sends out. Or they could be trying to keep the user experience simple, such that you never need to consider polarizing the test leads. Along these lines, a DC signal for measuring resistors - to avoid the wire-wound limitation while calibrating or measuring.
I sometimes launched a SMD component across the room using the tweezers, more often after some use. It seemed that I needed to squeeze harder to make connection. Under a microscope I could see some of the gold inside the very tips had worn through to bare nickel, with a broken edge where the wear stopped, as if flaking away happened. I'm glad I ordered the extra tips, but 2-3 days use seem a bit early to see that sort of gold shedding off due to pressure.
Conclusion ★★★★★
There aren't any reasons to hesitate buying this unit. My list of concerns shouldn't stop you from buying, because the price is so good! I feel this is 9/10 of the function of a full sized LCR meter for 1/10 the price. The unit is extremely accurate, easy to handle, easy to use. They really hit the mark with this one, and kept the price of admission low.
I recommend this to anybody who wants an LCR meter and can't justify buying a full-sized unit. With the ZT-MD1, you will get a much more useful tool than if you purchased a cheap-o multimeter around the same price just to get their inductance and capacitance function.
For those who already have big LCR meter, it's significantly more handy and convenient to use the tweezers for quickly assessing small components in or out of circuit. I found it produces results I can fully depend on. I am glad I have both tweezers and full-sized units in my lab.
User Manual
One year manufacturer warranty.
Data Export Log Example
The file name is Results.txt. The data shown below is the same as what was used in the accuracy graph shown above.
The information is tab-delimited text, easily imported into Excel with the appropriate import settings. This meter does not keep track of time, so the log is simply numbered. There is no provision to review the data on the device or manage the text file.
Each press of "HOLD" appends the file with one more line. If you move or rename the file, the meter will start a new one. There is a generous internal drive space, so you're never going to run out of storage.
Notice that the series equivalent resistance (Rs) is not logged with firmware V1.7. For instance, the "0L" measured was a 20M resistor. It showed in the display as Rs, but was recorded over limit. I made a comment to ZOYI that I would like Rs logged in a future firmware release. If they add it I will come back and update my post.
