Finally, we choose a budget multimeter with good functionality.
Two years ago, a post with multimeter testing was published. The price of the tested model Fluke 87-V starts from 40 thousand rubles, which is beyond the reasonable for the average user, for which the author was naturally scolded. Moreover, some users reasonably noticed that the DT 838 for 300 rubles would be enough to check the batteries. Thus, two poles of prices were covered, and whether there is something for intermediate money, but with good accuracy, it remains unclear. If interested - let's see.
At my disposal at work there is a good workhorse APPA 71 (Included in the State Register of SI at number: 25440-11 Certificate of inclusion in the State Register of SI is valid until: 03/21/21), it costs about 5,000 rubles - you can pull amateur, but still expensive Four years ago I bought the DT9205A, which was incomparably better than the 838th version, but it cost the same 300 rubles when ordering from China. About a year ago, I accidentally stumbled upon the AN8002 model - it attracted a tiny size, good functionality, a large digit capacity (6000) and a price of about 800 rubles. The device arrived and immediately pleased with the quality of performance. The package is minimalist - a pair of probes, a thermocouple, a soft case. A month ago, I saw the AN870 model with a bit depth up to 19999 and cost about 2,000 rubles. Naturally, I could not resist and ordered it. The other day, he also arrived and immediately pleased with a complete set: two standard probes, two wires with a screw connection, four screw-in chips, two terminals, two sharp screw probes, four crocodiles, a thermocouple and a semi-hard case. Unpleasant nuance: the standard test leads of both multimeters turned out to be very mediocre - during the test for short circuit, the values were dangling from 0.1 to 0.8 Ohm, after which they went harassed. Instead of full-time probes, we had to use a Chinese no-name, bought rubles for 100-200. Here are these beauties:
')
The test of the supply voltage AN8002 showed the following results: the device confidently holds the readings at a supply voltage from 4V to 2.2V, below 2.4V the battery discharge indicator turns on, below 2.2V the device turns off. In the AN870, the battery discharge indicator lights up below 2.5V, the device shuts off when it reaches 2.4V.
To test the accuracy of the measurement of resistance was used resistance magazine with KDPV. The minimum pitch is 0.1 ohm, the maximum value is 100 kΩ (if it is, then 99999.9). Especially carefully passed the moments of switching the limits - 200, 2000 ... for the DT9205A and 600, 6000 ... in the case of AN8001. We obtain the graph of the relative error:
DT9205A gives a ten percent in the left part of the graph due to an error in the lower order unit 0.1 Ohm. The following graph shows a larger resistance area:
DT9205A expectedly loses the race, while the leaders suddenly become Anengi. It is worth noting that the AN8001 values do not change at all after setting down for a couple of seconds, which is a clear marker of the end of measurements. At APPA 71, they hang out + -2 units of the lower rank. AN870 values go to the final for more than five seconds, after which the numbers stand still. For digit capacity it is necessary to pay with time, which is not very surprising.
Voltage tests were performed using Agilent 34401 and 34410 desktop instruments (multimeters) and Yokogawa 7651 (precision current and voltage source). The readings of the source were checked by the first device, which, in turn, was tested using an element of normal saturated X480. Since the temperature in the room was +28 instead of +20, for the completeness of the experiment, a calibration graph of the voltage X480 as a function of temperature was constructed:
Lines above and below the calibration curve show the allowable voltage range of the work item. Of course, the temperature shift is beyond the limits of accuracy and even the resolution of handhelds, but is a test of the calibration of test instruments. The older Agilent 34401 showed voltages 1.018235 and 1.018238 in two different polarities, i.e. the average value of 1.0182365, Agilent 34410 showed 1.018253 and 1.018244, i.e. the average value is 1.0182485. Both average values (two small asterisks near the Agilent signature) differ from the calibration curve by less than 10 µV, which is simply excellent - X480 has an accuracy class of 0.005, i.e. a tolerance of up to 50 µV is allowed. Multimeters in the range of 1V have a tolerance of about 40 µV.
Below is a graph of the relative error in measuring DC voltage. In addition to the AN8001 and AN870, the Fluke 15b was tested, since ARRA was simply not found (it happens at our place of work).
On alternating current, the accuracy of both devices turned out to be no worse than 1%, but the proud True RMS inscription does not correspond to reality - when adding a stand to the sine, the readings did not change, i.e. measurements go through a capacitor.
The thermocouple attached to AN8002 showed 96 degrees in boiling water at a pressure of 740 mm Hg, which is not enough (about three degrees), the thermocouple AN870 showed an honest 99 degrees.
Model number AN8002, because It was he who bought it home first, and he has a thermocouple input, unlike the AN8001.
Summary: both devices are impressed with their accuracy, functionality and price at the same time, which is rare. The AN8001 is compact enough to fit in a pocket, the AN870 has a full-sized handheld form factor. As a minus of the AN8001, automatic range switching can be noted - this is not always convenient, and some are just as annoying. However, its merits make it possible to safely write it down in thestaff of laboratory instruments. AN870 is devoid of this disadvantage - it has both automatic and manual range switching. The price is 2.5 times higher than the younger brother can scare away a simple radio amateur, but for the laboratory it is an excellent device for little money. The decision what device to take, of course, remains for the buyer.
I will attach the link and comment mdn-tech about finishing the range selection in 8001: If it’s important, you can disassemble and make it. There are contacts on the board. cm.
In the comments went examples with photos - this somewhat hinders the possible comment threads. Please hide the pictures under the spoiler, bring the price and at least tezisno voice, what is better than your options.
At my disposal at work there is a good workhorse APPA 71 (Included in the State Register of SI at number: 25440-11 Certificate of inclusion in the State Register of SI is valid until: 03/21/21), it costs about 5,000 rubles - you can pull amateur, but still expensive Four years ago I bought the DT9205A, which was incomparably better than the 838th version, but it cost the same 300 rubles when ordering from China. About a year ago, I accidentally stumbled upon the AN8002 model - it attracted a tiny size, good functionality, a large digit capacity (6000) and a price of about 800 rubles. The device arrived and immediately pleased with the quality of performance. The package is minimalist - a pair of probes, a thermocouple, a soft case. A month ago, I saw the AN870 model with a bit depth up to 19999 and cost about 2,000 rubles. Naturally, I could not resist and ordered it. The other day, he also arrived and immediately pleased with a complete set: two standard probes, two wires with a screw connection, four screw-in chips, two terminals, two sharp screw probes, four crocodiles, a thermocouple and a semi-hard case. Unpleasant nuance: the standard test leads of both multimeters turned out to be very mediocre - during the test for short circuit, the values were dangling from 0.1 to 0.8 Ohm, after which they went harassed. Instead of full-time probes, we had to use a Chinese no-name, bought rubles for 100-200. Here are these beauties:
')
The test of the supply voltage AN8002 showed the following results: the device confidently holds the readings at a supply voltage from 4V to 2.2V, below 2.4V the battery discharge indicator turns on, below 2.2V the device turns off. In the AN870, the battery discharge indicator lights up below 2.5V, the device shuts off when it reaches 2.4V.
To test the accuracy of the measurement of resistance was used resistance magazine with KDPV. The minimum pitch is 0.1 ohm, the maximum value is 100 kΩ (if it is, then 99999.9). Especially carefully passed the moments of switching the limits - 200, 2000 ... for the DT9205A and 600, 6000 ... in the case of AN8001. We obtain the graph of the relative error:
DT9205A gives a ten percent in the left part of the graph due to an error in the lower order unit 0.1 Ohm. The following graph shows a larger resistance area:
DT9205A expectedly loses the race, while the leaders suddenly become Anengi. It is worth noting that the AN8001 values do not change at all after setting down for a couple of seconds, which is a clear marker of the end of measurements. At APPA 71, they hang out + -2 units of the lower rank. AN870 values go to the final for more than five seconds, after which the numbers stand still. For digit capacity it is necessary to pay with time, which is not very surprising.
Voltage tests were performed using Agilent 34401 and 34410 desktop instruments (multimeters) and Yokogawa 7651 (precision current and voltage source). The readings of the source were checked by the first device, which, in turn, was tested using an element of normal saturated X480. Since the temperature in the room was +28 instead of +20, for the completeness of the experiment, a calibration graph of the voltage X480 as a function of temperature was constructed:
Lines above and below the calibration curve show the allowable voltage range of the work item. Of course, the temperature shift is beyond the limits of accuracy and even the resolution of handhelds, but is a test of the calibration of test instruments. The older Agilent 34401 showed voltages 1.018235 and 1.018238 in two different polarities, i.e. the average value of 1.0182365, Agilent 34410 showed 1.018253 and 1.018244, i.e. the average value is 1.0182485. Both average values (two small asterisks near the Agilent signature) differ from the calibration curve by less than 10 µV, which is simply excellent - X480 has an accuracy class of 0.005, i.e. a tolerance of up to 50 µV is allowed. Multimeters in the range of 1V have a tolerance of about 40 µV.
Below is a graph of the relative error in measuring DC voltage. In addition to the AN8001 and AN870, the Fluke 15b was tested, since ARRA was simply not found (it happens at our place of work).
On alternating current, the accuracy of both devices turned out to be no worse than 1%, but the proud True RMS inscription does not correspond to reality - when adding a stand to the sine, the readings did not change, i.e. measurements go through a capacitor.
The thermocouple attached to AN8002 showed 96 degrees in boiling water at a pressure of 740 mm Hg, which is not enough (about three degrees), the thermocouple AN870 showed an honest 99 degrees.
Model number AN8002, because It was he who bought it home first, and he has a thermocouple input, unlike the AN8001.
Summary: both devices are impressed with their accuracy, functionality and price at the same time, which is rare. The AN8001 is compact enough to fit in a pocket, the AN870 has a full-sized handheld form factor. As a minus of the AN8001, automatic range switching can be noted - this is not always convenient, and some are just as annoying. However, its merits make it possible to safely write it down in the
I will attach the link and comment mdn-tech about finishing the range selection in 8001: If it’s important, you can disassemble and make it. There are contacts on the board. cm.
In the comments went examples with photos - this somewhat hinders the possible comment threads. Please hide the pictures under the spoiler, bring the price and at least tezisno voice, what is better than your options.
Source: https://habr.com/ru/post/417401/
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