What does your multimeter show (voltage or weather on Mars)?
As long as you have a single multimeter in your household, you will not have any problems – your devices contain exactly the voltage that it shows (smiley). But as soon as you have two or more multimeters, the question immediately arises: which of them can be trusted, and who is outright lying with each measurement (and how much and in what direction)?
There are two ways to solve this problem: either find access to a reference certified multimeter with 5+ digits (the more the better) and compare the readings of your devices with its readings, or use special reference voltage boards.
It is clear that it is better to have access to a reference multimeter, but few people have this opportunity. In this sense, it is much easier to use boards from Aliexpress, but here we are faced with traps skillfully set by Chinese “business optimizers” (you can’t just take and sell an unremarked reference voltage chip).
We will talk about all this further, and at the same time I will share my impressions of the multimeters that took part in this study.
❯ AD584
There are many reference voltage boards on Aliexpress; one of the most popular options are boards based on various modifications of the AD584 chip from ANALOG DEVICES. Since the original chip from ANALOG DEVICES is not cheap, we are not talking about using new original chips in boards – the Chinese claim that they use, although used, original chips.
And here there are several levels of wiring:
Level 1. Basic. The essence of the layout is that cheaper and less accurate (but original) microcircuits with the “J” index are taken and relabeled into a more accurate and expensive version with the “K” index. It’s meanness, of course, but not the worst option, since the original chip is still used and buyers are left with at least more or less decent temperature stability of the output voltage.
Level 2. Generally unknown what, not AD584. It’s hard to say here, but, apparently, under the guise of AD584, unknown products from Chinese microcircuit manufacturing (I would say Chinese alchemy) can be installed in boards.
Level 3. Complete trash. This category includes boards with obvious trash on board, such as incorrect circuit design or reference voltage inscriptions, printed on a piece of paper with the same values for all sold boards.
In general, buying such a board is still a lottery with approximately the same chances of success. It should also be noted that photographs of boards on Ali have nothing to do with what they will actually send you. I spent a long time choosing the normal option and in the end they sent me something like “Wiring No. 1”.
When examined under a microscope, a clear re-labeling of the microcircuit by the laser is visible. This is precisely re-labeling because the inscriptions on the original microcircuit are painted.
The following signs indicate that my option belongs to the first level of wiring (J – K):
- The microcircuit has a “shabby” appearance, which a new chip cannot have.
- The chip has clearly been relabeled, which is not necessary for a new chip.
- The board demonstrates stability – under different conditions and different ambient temperatures it produces the same voltages.
- Very close readings of test multimeters indicate that the inscriptions with a felt-tip pen are related to reality.
And the fact that the values of the output voltages are written by hand gives hope that these are, after all, real values recorded by a “Chinese operator” from the screen of a reference multimeter.
❯ UNI-T UT70A
An “oak” device in every sense of the word – only two decimal places, but a completely indestructible case, plus it is even equipped not with a cover, but with a powerful protective shell. The rest of the test participants look like slender “office boys” against the backdrop of the brutal UNI-T UT70A. On the side of the shell it says “PROFESSIONAL” (visible in the photo).
In general, if you ever need to climb a pole to measure something on a panel, then the UNI-T UT70A will be the best assistant for this activity. I think falling from a pole will not affect its functioning in any way (smile).
The advantages of this device also include its omnivorous nature – in addition to the standard set of capabilities for this type of device, it also measures capacitance, inductance, etc.
❯ UNI-T UT61E+
A multimeter that needs no introduction and is the “de facto standard” for amateur (and not only) measurements. Excellent price/quality ratio and universal recognition.
There is no particular point in talking about this device, I will only note that compared to its older brother UNI-T UT70A, it looks rather flimsy. It’s definitely better not to drop it from the pole; I wouldn’t recommend dropping it even from the table.
❯ BSIDE S11
A frankly hipster option with unique usability. To begin with, its probes are inserted from below and this multimeter cannot be placed vertically – its purpose is to work lying down (smile). By the way, his probes are non-standard.
Like a full automatic machine (we’ll see how this machine works later), there is no ability to measure current strength and other similar “nuances”.
In general, it leaves a very ambiguous impression, although, I must say, it is he who is always lying around somewhere, and not in a box (and this already says something).
❯ ZOYI ZT-703S
Where would we be without ZOYI ZT-703S? This season it is almost the most fashionable device. The device is also very ambiguous.
The advantages include an excellent design (it is simply pleasant to hold in your hands and a pleasure to work with), which will give odds to all other test participants. It also very conveniently implements control of a complex complex (multimeter + oscilloscope) using only four function buttons and a menu button.
The disadvantages include the completely disastrous implementation of the folding leg – it is dramatically flimsy and does not allow you to work normally with the device in a vertical position and… the fact that this is not an oscilloscope. More on this in a little more detail.
In all advertising, ZOYI ZT-703S is stated as a portable oscilloscope. This is wrong. You can’t call this an oscilloscope – there are a lot of errors in the firmware, the shape of the signal and its measured values depend on the set measurement limits (which absolutely should not happen in a normal oscilloscope). At best, this can be called a display meter and a preparation for writing normal firmware in the future (but who will do this?).
But paradoxically, the ZOYI ZT-703S is the most convenient multimeter of all participating in the test. It is he who reaches out when he needs to measure something. And the opportunity (albeit crookedly and inaccurately) to see the shape of the signal under study puts an end to the choice and the ZOYI ZT-703S receives the “editor's choice” prize.
❯ YAOREA YR1035+
YAOREA YR1035+ is not a multimeter in the conventional sense of the word – it is a specialized battery tester. It was included in this review because it measures voltage and resistance, and does it extremely accurately, and it would be wrong not to test it.
Briefly: the tester is original and specific, but of exceptional quality for its purposes.
❯ DL24
This device is out of competition, since it is not a multimeter, but an electronic load. But since its display displays an incredible number of decimal places, it was interesting to find out how much such “accuracy” corresponds to reality.
❯ Stand
In order to eliminate the influence of network noise and noise from DC/DC converters, the reference voltage board was powered directly from a 12-volt battery. The range of permissible input voltages of the board is from 12 to 24 volts.
To measure voltage with multimeters, their supplied cords were used.
❯ Range 2.5 V
Let's start testing with the 2.5 V range. Here and in subsequent tables, the participants are ranked according to the quality of the result obtained – from best (top) to worst (bottom).
The BSIDE multimeter has two voltage measurement modes: “special” and “auto”, so there are two lines for it in the table.
❯ 5V range
Range 5 V. Noteworthy is the result of a discrepancy of only 0.001 volts between the standard and the UNI-T UT61E+ readings, which indirectly indicates the authenticity of the AD584 chip on the reference board used.
Please note that all reading deviations are negative and only the BSIDE S11 reading deviation in Auto mode is positive.
❯ Range 7.5 V
In the 7.5 V range, the picture is approximately the same with the same distribution of participants’ places (only the electronic load DL245 slightly improved its result.).
❯ 10V range
Well, the final test is in the 10 V range. At this test voltage, all deviations of the obtained values became negative.
❯ Pivot table
Now let’s summarize in one table the percentage of deviations of the measured voltage values by all test participants.
And for greater clarity, we will present this information in graphical form. On the vertical axis are the deviations of the measured voltage from the reference voltage in percent. On the horizontal axis there are four blocks of values in the ranges of 2.5, 5, 7.5, 10 V.
The colors of the values on the graph correspond to the conventional colors of the multimeters in the summary table.
Now a little about the interpretation of the results obtained during testing.
UNI-T UT61E+
The recognized favorite UNI-T UT61E+ performed best. The values of its readings differ minimally from those announced on the reference board.
YAOREA YR1035+
Almost on par with the UNI-T UT61E+ is the YAOREA YR1035+ battery tester, which is not surprising, since this is another recognized “de facto standard” for its field of application (measuring battery parameters).
BSIDE S11
Then miracles begin. If the first place was shared between UNI-T UT61E+ and YAOREA YR1035+, then in second place, quite unexpectedly, was the “hipster” and seemingly completely frivolous BSIDE S11.
Moreover, with regard to BSIDE S11, the following was revealed: it turns out that it normally measures voltage only in a mode specially designed for this (which must be turned on additionally with a button), and in the “Auto” mode its readings begin to differ from its readings in normal mode. In addition, they also “jump through zero” in different voltage ranges, and in the 10 V range they generally acquire an indecent error.
And there are two points here. Firstly, you will never know about this feature of the multimeter until you conduct such testing. Until then, you (with the same measured voltage) will have different numbers on the screen in different modes. So you can suffer for a long time and wonder why your scheme works somehow strangely.
And secondly, based on these data, the “Auto” mode, which is announced and is the main one for BSIDE S11, is practically unsuitable for it, at least with regard to measuring DC voltage.
ZOYI ZT-703S
The handsome and universally beloved ZOYI ZT-703S managed to lose not only to the favorites UNI-T UT61E+ and YAOREA YR1035+ (which is not so offensive), but also to the “upstart” BSIDE S11 (which is something I never expected).
It turns out that not only is the oscillographic part defective, but there are also problems with the measuring part. But, on the other hand, the network is filled with laudatory reviews of the ZOYI ZT-703S and perhaps these are only problems with my specific copy.
Electronic load DL24
The DL24 electronic load performed generally well, but, as they say, there are nuances. The graphs clearly show that the error varies depending on the input voltage. And the lower this voltage, the greater the error. You also have no way of knowing this until you conduct such testing. Until then, you will wonder why your “ends meet” do not meet in your measurements.
And during the testing process, another feature of the DL24 was revealed – its last digit “jumps” completely indecently, which does not happen with any multimeter. It is difficult to say what is the reason for this behavior. Maybe this is a feature of the operation of its ADC, or maybe the developers simply decided not to bother smoothing the output values.
UNI-T UT70A
UNI-T UT70A confirmed its “dumbness” and became an outsider in testing with a result of almost half a percent error in the 2.5 V range. But something tells me that this doesn’t bother him much (smile).
❯ Results and conclusions
The ZOYI ZT-703S is best suited for everyday use due to its ergonomics and the presence of a pseudo-oscilloscope on board (with which you can quickly view the shape of the measured signal). The error of its measurements, although increased, is at an acceptable level for most non-critical applications.
In the case where high accuracy is needed, you will need to uncover the UNI-T UT61E+ or YAOREA YR1035+.
The little BSIDE S11, which is always at hand, can successfully replace its more advanced brothers. Just remember to switch it from auto mode to DC voltage measurement mode.
In general, the DL24 electronic load can be trusted, you just need to remember that it actually does not have the last discharge and that the lower the measured voltage, the greater the error in its readings.
UNI-T UT70A remains on the bench and awaits its finest hour in some extreme situation when its indestructibility is needed.
Well, the main conclusion: you need to know your technique. It needs to be tested (calibrated) before working with it (unless, of course, you are serious about your business).
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