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Digital panel meter - Voltmeter / Ammeter - made in China.

CMS 14604 68
This content has been translated » The original version can be found here
  • Hello, my dear electrode colleagues.

    Today I decided to present you a cheap Chinese voltmeter and ammeter, in one neat panel housing. The purchase cost is about PLN 6

    Digital panel meter - Voltmeter / Ammeter - made in China.

    I decided to take this step due to the fact that in a certain thread on the forum, there is a discussion about the accuracy of measurements of this type of meters. Gentlemen, they are shouting over each other with arguments, but somehow no one has checked the reality. Even if he did, he didn't show the results.

    Let's start with what the manufacturer says, because we must have a reference point.
    1. Of course, "high quality" is in the first place :) .
    2. Next, this - let's call it conventionally and for the purposes of this article - "multimeter" prides itself on measuring voltage in the range of 0-100V DC.
    3. The ammeter should indicate correctly in the range of 1-10A, which the seller clearly indicates and asks not to leave negative reviews due to inaccuracies in the range of less than one Ampere.

    The fact that the ammeter is already activated at 0.01A, but its indications in the range of up to one Ampere do not match the "real" ammeter. However, in the case of my copy, the indications above one Ampere were also not very accurate.

    Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China.
    Sequentially 200mA; 250mA and 300mA. As you can see, it lies on average by 20mA

    Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China.
    Now 500mA; 750mA and 1000mA. We can see that it distorts even more, because in the first two cases by 0.03A and in the last one even by 0.04A.

    Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China.

    Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China.
    As you can see, at higher currents it is better, but still not very precise.

    Digital panel meter - Voltmeter / Ammeter - made in China.

    It's just that this is the state after taking it out of the package, and yet we have two tiny "peers" for REGULATION.

    After that, it turns out that in the lower ranges it can be quite accurate

    Digital panel meter - Voltmeter / Ammeter - made in China. Digital panel meter - Voltmeter / Ammeter - made in China.

    I noticed that a large number of users have problems connecting this device.
    It is actually very simple. Just take a look at the diagram below.

    Digital panel meter - Voltmeter / Ammeter - made in China.
    Image source

    The voltmeter has the advantage that it can be powered from the measured voltage, if it is not lower than 4V. If you want to measure lower voltages, you should supply power from an external source, for example a 6F22 battery (a bad idea in the case of two, even small LED displays) or a power supply e.g.. plug 5-30VDC with a minimum capacity of 100mA.
    Please note that this ammeter works "one way only". Reverse connection will short-circuit the output of the multimeter power supply system, in such a situation, if the power supply system is not protected, it may be dismal ...


    I believe that for such money, this "measure" is worth attention. After a child's play of "calibration", the results on the display can exactly match the indications of a "real" voltmeter (for which you have to pay at least ten times as much), even in the range of less than one Ampere, as shown in the pictures above.

    Best regards.
    CMS

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    About Author
    CMS
    Administrator of HydePark
    Offline 
    CMS wrote 6705 posts with rating 1699, helped 153 times. Live in city Warszawa. Been with us since 2004 year.
  • #2
    h3c4
    Level 14  
    Worth the money, but after six months the LEDs in the segments burn out.
  • #3
    jousto
    Level 17  
    h3c4 wrote:
    Worth the money, but after six months the LEDs in the segments burn out.

    For me, the same has been working non-stop for 3 years and I have not noticed any difference in the lighting of individual segments yet. The fact is that in the lower range of current measurements the indications are not stable or accurate, but it is enough for my applications.
  • #4
    Galareta
    Level 22  
    Are they falling completely or are the segments only losing brightness?
  • #5
    mariomario
    Level 18  
    I have the same gauge. It is not perfect, but it is suitable for an "amateur" power supply. For example, for me:

    - When the display shows a voltage of e.g. 4.00V, it is actually about 4.18V
    - When the display shows a voltage of e.g. 12.0V, it is actually about 11.80V

    The indications are very "non-linear", PR regulation does not help. But the purchase price (1.7 $ + free shipping) eliminates this drawback :)
  • #6
    szeryf3
    Level 22  
    For such money, the meter is worth attention, but it can be used as a beautiful gadget.
  • #7
    viwaldi1
    Level 24  
    The characteristic feature of "Chinese electronics" is that individual units are very different from each other. A test taken is about as reliable as a statistical survey based on one opinion ;) Checking a batch of goods will also do nothing, because the same housing can accommodate quite different electronics with different functionalities. And the Chinese will not inform you that he has changed something :D
  • #8
    anet870
    Level 26  
    Measures negative voltage? e.g. measuring symmetrical voltage with two such meters.
  • #9
    koala106
    Level 39  
    I have installed a dozen or so meters of this type and there are several types - the most accurate are the ones with automatic range change - he sent me quinol at one time instead of the ones described in the article. Indications at the level of + -2% from the model Metex, i.e. acceptable. I did not do the calibration with PRs, because I did not have such a need. By the way, check the colors of the wires - because once I got the meter turned into a garbage can.
  • #10
    Simon12
    Level 11  
    Send a link to the action you bought on.
    best regards
  • #11
    User removed account
    User removed account  
  • #12
    kot mirmur
    Level 33  
    Hello forum members. I just bought a similar meter, I am going to use it for measurements in a rectifier for charging Pb batteries. Rectifier based on the RegPro-4 module from Design OFFICE /www.regulatorytyrystorowe.pl. However, one thing puzzles me - the cross-section of the ammeter test leads. Will they actually withstand 7-8 amps for about an hour?
  • #13
    mariomario
    Level 18  
    kot mirmur wrote:
    Hello forum members. I just bought a similar meter, I am going to use it for measurements in a rectifier for charging Pb batteries. Rectifier based on the RegPro-4 module from Design OFFICE /www.regulatorytyrystorowe.pl. However, one thing puzzles me - the cross-section of the ammeter test leads. Will they actually withstand 7-8 amps for about an hour?


    They will not stand, they are thin as threads. I personally "cut" these wires and soldered those with a 1.5mmkw cross section. Moreover, there were significant voltage drops on these original "threads", so I fired them.
  • #14
    gimak
    Level 39  
    I used such meters in rectifiers to charge the batteries. Earlier, I also checked the accuracy of the indications with an ordinary digital multimeter - the results were similar to the author of the topic. However, when comparing the indications of analog meters with the current range of 10A and voltage range of 30V, the differences are practically imperceptible.
    CMS wrote:
    Please note that this ammeter works "one way only". Reverse connection will short-circuit the output of the multimeter power supply system, in such a situation, if the power supply system is not protected, it may be dismal ...

    For four I bought one (the first one was installed), in which I connected the masses (black wires) of the module power supply and the measurement one. After an hour or so, a bubble appeared and the display went blank. The circuit lowering the voltage to 3V fell in it. Something more had to fall, because when I gave the voltage 3V after this system, the display was still dark.
    After this event, I read that when the module is powered with the measured voltage, the mass (-) of the module power supply should be free (not connected). I do not know if the combination of these masses was the reason for burning or I came across a faulty module.
  • #15
    CMS
    Administrator of HydePark
    In my case, both grounds are connected to each other on the PCB.
  • #16
    Szyszkownik Kilkujadek
    Level 36  
    r-mik wrote:
    It is not a miracle, but it is suitable for a workshop power supply as long as we have one output. Like several, the measurement from the mass disqualifies the ammeter from use.
    I plan to give a switch to select which output to measure. :-D
  • #17
    gimak
    Level 39  
    CMS wrote:
    In my case, both grounds are connected to each other on the PCB.

    It seems I was unlucky, with the next prophylactic (-) power supplies I left in the air.
  • #18
    Szyszkownik Kilkujadek
    Level 36  
    So we connect only the black one from the ammeter to (-), do not connect the second one thinly?
  • #19
    Mikusiek48
    Level 14  
    Is it possible to make some simple circuit that will allow me to measure negative voltage and current to this meter?
    If anyone has a solution, please share it with me.
    Thank you in advance :)
  • #20
    gimak
    Level 39  
    Szyszkownik Kilkujadek wrote:
    So we connect only the black one from the ammeter to (-), do not connect the second one thinly?

    I after damaging one module in which I connected this thin black wire with the black one from the ammeter and after finding it
    https://obrazki.elektroda.pl/7983994200_1520329132.jpg
    in the next connected modules I left the thin black wire in the air.
  • #21
    Szyszkownik Kilkujadek
    Level 36  
    Thanks @gimak !! One picture worth more than 1000 words.
  • #22
    koala106
    Level 39  
    mariomario wrote:

    They will not stand, they are thin as threads. I personally "cut" these wires and soldered those with a 1.5mmkw cross section. Moreover, there were significant voltage drops on these original "threads", so I fired them.

    In one device, these Chinese conductors melted the insulation at 7 A charging the battery - it is best to solder thicker directly to the board or give a solid plug with a wire
  • #23
    kot mirmur
    Level 33  
    Buddy Koala, in quinola the current in the cables is probably less frequent, that's why they give such thin-chees. I think I will use inserts from old connection cubes, with metal plates under the screw, on the other hand I will tighten the 2.5 square wires and it should be enough.
  • #24
    koala106
    Level 39  
    Everything is rarer with them ...
    The best are the jumper cables complete with a powerbank - the outer diameter of 8mm is impressive - with a cable between 0.75mm2 and 1mm2 inside.
  • #25
    kot mirmur
    Level 33  
    They are usually small, smaller houses, cars, shoes, etc. Small cars don't need a lot of electricity, so these cables have a small Cu.Che Che cross-section !!!
  • #26
    Szyszkownik Kilkujadek
    Level 36  
    Price works wonders. There is demand and there is supply. ;-)
  • #27
    1996arek
    Level 20  
    @CMS What is this power supply that you are testing the meter with? I can see here the construction of dj-MatyAS.
  • #28
    CMS
    Administrator of HydePark
    1996arek wrote:
    @CMS What is this power supply that you are testing the meter with? I can see here the construction of dj-MatyAS.


    You see well. I got it from the mentioned user as a gift.
  • #29
    anet870
    Level 26  
    anet870 wrote:
    Measures negative voltage?

    No.

    There is a way to measure negative voltage?
  • #30
    bestler
    Admin of DIY, Automation
    Digital panel meter - Voltmeter / Ammeter - made in China.

    They are now popular right away with an AC metering transformer. I use it in a workshop board and it works perfectly well here.