Too good to be True(RMS)? Aneng AN8002 False or True? RMS meter review
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- Опубликовано: 6 сен 2024
- This was suggested to me in comments, and I jumped at it straight away! True RMS multimeter for £10? I want it yesterday!
In this video I decided to do a review and test if Aneng AN8002 really is a True RMS device. Watch for my conclusion.
In the video I used ElectroDroid app - really cool gadget to have on your phone if you like tinkering in general - lots of conversion tools and general electronics engineering cheat sheet.
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The meter isn't actually as far out as you assume. It is the measurement rationale that is wrong. Tefatronix is close to the solution. RMS meters (usually) measure the RMS of the AC component of the signal. The resulting RMS values for a 10V sine wave are: Sine wave - 10V, half-wave rectified - 5.45V, full-wave rectified - 4.35V (all according to Fluke). For a 5v PWM signal, they are: 25% - 2.17V, 50% - 2.5V, 75% - 2.17V. It looks as if the peak to peak output of the Arduino could be closer to 4V giving, 1.74V, 2V and 1.74V respectively. So, don't rule it out as rubbish just yet!
Hugh McCullough i still like this meter. just the rms measurements did not add up for me when comparing with values i got from the app. i did more tests with 5v positive square (not from druino) at 50Hz, and still was not right (or at least not what the calculated value suggested) I will do more tests on a vid soon ;)
As I said in my first comment, you are calculating the composite RMS voltage on your app. (AC and DC components combined). Meters nearly always measure only the AC component (as if zero is always at the middle value of the signal). Can your app. give you the RMS value of the AC component of the signal? If not, any meter you test will look wrong. Look at the values I quoted from Fluke (the experts by a mile!) and see if you can get the app. to replicate them. Then you will know that you are on the right track.
+Hugh McCullough thanks!
Yes, Hugh McCullough is right.
The APP shows the AC+DC RMS value and the multimeter the AC RMS value. Because of this the values appear to be incoherent, but they are well coherent. The AC+DC RMS value will be the vectorial sum of AC value and DC value (sqrt(AC^2 + DC^2)).
This meter looks to be very interesting (mainly by the low price)
The best part of this video by far (for me, anyway) was your discovery of the manual-ranging button pad. That's a feature I miss in most (all?) cheap auto-ranging multimeters. I tried it out on mine, and using manual ranging vastly increases the speed of resistance measurement. In auto-ranging mode the meter takes around 3 seconds to measure the lead resistance when the leads are shorted together (and the same again to display OL when the leads are separated). In manual mode, it takes about half a second in any range.
Given the case design there doesn't seem to be any easy way to mount an appropriate button on the back that would make contact with this pad, but there is plenty of room to drill a small hole in the side of the case for a small pushbutton. I wouldn't want to try soldering leads from that directly to the tiny, tiny traces on the pad, but one side of the pad leads to a much larger pad (a test pad, perhaps; it's marked "PT1.1") and the other goes to the negative terminal of the battery case which is quite large. So it would seem not too difficult a project to add a manual ranging button to this meter, which I think I will try doing one day.
Regarding your RMS measurements and calculations, I don't know a huge amount about this but they look pretty dodgy to me, too. I think that it would be a good idea, before doing another RMS test, to find out exactly why one would want to use an RMS measurement (rather than, say, a peak to peak or average voltage measurement) when measuring an AC voltage. Once you know the purpose of it, it will be much easier to design tests to see if the meter meets that purpose.
+Curt Sampson thanks! A followup on this RMS measurement is in the plans. It will just be a while now due to relocation :/
randomtronic pls just change the title!
I check all my meters for RMS readings and upper frequency, AC+DC and so on. Aneng 8002 is well in spec over 1 kHz. Actually at 1.5 kHz is perfectly usable. Your results are based on wrong calculations.
+radu3g Thanks. I agree. I blindly trusted what the app said, and that didn't correspond to the meter readings. I have to follow this up.
I just have seen AN8002 testing video where it had hard time measuring a squarewave above 100 Hz. ruclips.net/video/GbmVpS2cQuk/видео.html
@George Bonak You mean you have measured with another meter and it's 5v spot on? usb voltage can go often up to 5.5 volt.
For the temperature it's not much you can do. Thermocouple measuring is never accurate. You can buy a pretty cheap thermometer which is far more accurate.
can i. ask for the firmware? mine is inaccurate
I would perfer a comparison between Fluke/Sanwa multimeter and Aneng to UNI-T and Aneng.
You'r mixing up TRMS which is for AC, and AC + DC which is the meander you'r trying to measure with AC settings on. The meander (square wave) IS NOT the AC signal! "Electric charge in alternating current (AC) changes ***direction*** periodically". In DC PWM signal there is no ***direction*** change of the current, only the intensity.
You should've switched it to DC mode to measure the DC PWM "RMS" level, which is actually just the average.
driveparty thanks, i will follow this up when i get my gear back together.
Take note, that for most meters, even high end ones, true rms does not necesarily mean it can do it at high frequencies, and 1kHz is a high frequency in this context, see the note about that in the bm235 manual fro eevblog (www.eevblog.com/product/bm235-multimeter/ specifications link) for example. Without consulting the docs, I doubt 1khz testing is that useful for rms. There is a thread or two about this meter at eevblog including links to the chipshet datasheet somehwre, it goes under various names.
James Sleeman thanks. it didnt cross my mind that 1kHz would be too high of a frequency. 10kHz maybe, but 1kHz is almost DC, right? lol, i will look into this, thanks for pointing this out. This meter though didn't measure rectified 50Hz sinewave correctly either, unless it loaded the circuit heavily enough for the voltage to drop significantly below open circuit voltage. more investigation needed ;)
I tried one of these from another brand at 50-500hz with some various waveforms (sine, square, triangle, etc) from a pc soundcard and results were rather close to the expected truerms value... For the price you really can't knock those little things.
I had problems with AC measurements taken on a Harbor Freight freebie DVM and now I check all my meters with a simple test to make sure the AC values that are taken are not totally bogus. I take a regular battery (AA, AAA, C, D, 9v) and measure it on DC VOLTS setting. Then I check it on the AC VOLTS setting. On the AC setting, a crappy DVM (like Harbor Freight's freebie) will measure roughly double the value that was given when measured on the DC setting. I discovered this when testing one of my power supplies for AC ripple using a cheap DVM. The 13.8 volt supply was measuring about 28 volts AC!!! I didn’t have an oscilloscope at that time and spent quite a while checking every component in the circuit. After finding no problems, I checked it with my "GOOD" True RMS DVM and found that there was only millivolts of noise on AC!!!! Both meters were giving similar results on the DC settings but were disastrously different on AC! Thanks for your videos!
The frequency measurement made in the AC Volts mode might be as expected. It does state in the manual that it's designed to measure high volts and low frequency. I can't quote the manual as it was only briefly shown in another video about the AN8002 and I don't remember which one!
Soon, when i get my gear back online I will follow this meter up, i promise :)
The freq on the voltage setting is for low frequencies higher voltage.. The freq setting is low voltage high frequency, meter works as it should. And the non True rms meter is called averaging meter so the value should go up with rectified signal as it stays above 0 unlike sine wave i believe
Possible design flaw:
Meter was wired up to measure a lithium ion cell voltage while meter was off. After the switch was moved one click to V, the 4 volt battery
measured only about 0.2 volts and smoke began to rise from the red lead. It then rapidly melted in two. The meter was then turned off. Replacing the lead and turning the meter on, the meter measured 3.8 volts and seems to be working fine now. Has anyone else encountered this?
Regarding the fuse if anyone needs to replace them the actual dimensions of the fuse when you look for them to buy are 3.6mm X 10mm. One is 600ma the other is 10A I have two of these. For the price I am very happy with them.
In the manual it says: " Do not input voltage exceeds 36V DC or 25V AC when you are at the setting of measuring current"
What's that really means? I cannot measure, lets say for example, how much current a 100w 220v bulb light draws ? ( I know I don't need the multimeter for that, it's an easy convenient formula to calculate it).
Or it is just a safety precaution to not accidentally measure voltages above that range while the multimeter dial is set on "A", "mA" and ruin the multimeter?
Further to my other comment, I have a richmeters branded version of this meter. The specs on page 2 of the "manual" are what you want, take note "True RMS (Other waveforms exceed 200Hz are for reference only)" which indicates to me that anything over 200Hz and your results are not useful. Your fully-rectified waveform is 100Hz right, so already you are getting up there. Try slowing the PWM frequency way down to 50Hz and re-running the tests on it.
+James Sleeman cool, will do a follow up! Thanks!
Can anyone tell me if the backlight should turn off automatically? My does and it bothers the hell out of me! Maybe I have a lemon/dud/screwed up meter? Maybe I should read (lol!) the manual? Thx!
Nokia, what's that? My favorite true RPM's test is a cheap D.C. To A.C. Inverter that outputs a wired PW square wave for the A.C. Output.
Not to question your measurement, but are you sure the PWM signals on the Adriano are 5V, or are they using the 3V leg? I honestly don't remember, it's been a while since I played with Arduino. I do remember it does have two voltage legs, one that's 5VDC and one that's 3VDC. Or was it 3.3VDC on the second leg?
Thanks. I re did the test, vid coming soon :)
Just so you know, that 600ma fuse is most likely a 500ma fuse that will blow at a much lower setting. at least is was in mine
+tycoon345 thanks
Nice review! I have this one on my shopping cart in Banggood but will wait for the follow up video
+Nahuel Pablo García Hi, thanks. Just some heads up, it will take so.e time for the follow up, as i am in the process of moving. From all the comments i received it seems the RMS is working, and the calculated value from the app was not correct (i think app shows combined ac & dc value, and meter measures only ac component) Overall i do like this meter though for what it is. Considering the price, go for it if that's what you need. Cheers!
I think the problem that you got so weird results while measuring the PWM on the arduino was, that usually the RMS chips integrate only to a certain frequency, usually between 400 and 1000Hz max. No idea of the specs of this meter, but I assume it will be even much lower. So if you lower the frequency on the Arduino way down, results will make more sense. This is also the reason, why you can't read the frequency on this meter in AC mode on the PWM outputs running at 1kHz :), frequency is simply too high in this mode. It also can be, that the meter can only see the AC component in AC as stated below, so it has some problems with the full wave rectified measurement in AC...or lets say, it shows other results than you expect, because you would have to measure and add the DC component too ;). Anyway, the meter doesn't look bad as an entry for basic electronic work, I would probably prefer the bit more advanced AN8008 :).
redcatimaging thanks, good comment. I learned an lot from responses on this video. I probably rushed this video a bit and didn't think everything through as i should. Cheers.
It was anyway a very interesting title and you had a good intension and when you've learned something from the comments, well even better :). The AN800X meter series is still interesting, it does look nice and I like the form factor (I even thought a second about buying one...but I have enough ;D). For what it is and what it costs, they seem to be not bad meters, especially for basic measurement stuff in a very compact format and the meter might really be the cheapest basic TRMS meter on the market :). Cheers :)
Hi, maybe my assumption is not correct, but if you have a 0/+5V square wave, doesn't it theoretically have both a DC and an AC component (it seems like you've been measuring only the AC component of the signal)? If I recall correctly, the True RMS AC+DC value would be sqrt(DC^2+AC^2).
Anyway, seems like a semi-decent meter, however the fuses seem too small (btw I also saw a PTC right under the epoxy blobbed chip)... if there was a $20 version with better protection, that would be great...
TefaTronix likely the issue with inaccurate readings was due to bandwidth/frequency. I have to re do the tests with square at lower frequency, a few tens of Hz maybe. Lets see, I would love for the readings to stack up, because I really like this little meter ;)
Try testing it with a symmetrical or at least AC-coupled square wave. This meter seems to be based on the DTM0660 chipset, the same chip that's used in my UT139C meter (although it's not blobbed there), which can measure the RMS value of a symmetrical square wave or an AC coupled triangle wave of a few hundred Hz (I think I tested up to 1kHz - not sure if I tested it up to 500 Hz or 1 kHz) on the AC range correctly. Haven't tested other waveforms.
It is painful to follow your RMS calculations. I suggest that you just use another true RMS meter for result verification.
By the way, non-sinusoid wave contains higher order harmonics. The removal of harmonic components by the meter bandwidth will lead to smaller readings.
GardeningZ thank you. you are right, i was wrong. i blindly followed the calculated value in the app without putting much thought into it. i will clarify this as soon as i get my camera back.
No worries. It is very difficult to finish lengthy calculation in one shot under pressure. Even my professor sometimes makes error on the white board.
It was showing 50% because you were picking up mains from the environment and when you measured the Arduino it was not showing anything because that range needs much higher amplitude to measure on the AC Hz.
(21:50) - Full wave peak voltage was 19.2v, not 14v. That's why you are getting spurious result.
(I think...)
What is the maximal Temüeratur which allowed for the probes? I want to measure the temp of my soldering iron which is about 380°C.
Diodes need a minimum current to conduct, without a load you can not measure. Often is the Rin of the meter just enough but if not you get fantasy readings (i tested this with several meters and a >1G meter showed over 100V instead 6V)
(0:25) - Actually, I would say £12 with some change, the change being 82p.
I suppose it depends on your perspective.
And I notice you are using a Lidl's own brand (Parkside?) screwdriver there. Nice! I have a set of these. Comes in a nice case. Chrome vanadium, excellent quality for the price.
Great video.
Please, keep 'em coming !
Will do, thanks!
Batteriees are also from lidl And easily Best value for money there is.
Hi.God video. Would you recommend this multimeter? Do you have 20 dollars more quality ?
Can I ask you guys please here? is it possible to use 3.7 rechargeable batteries for this multimeter?
(in manual for AN8001/8002 is mentioned: power supply 3V (2×1.5V)
It seems to be quite high 7.4V vs. 3V.
chudzo skruo sorry buddy, 7.4v will kill it. Why rechargeable though? A set of AAs will last in the DMM for AGES...
Hi, I thought that even little that part with lifetime of standard batteries, thanks for make it quite clear and certain. I am quite new in this "field", sorry for newbie question (was trying find it on itnernet but...).
You are welcome ;)
I am still confused by the comments is this meter true RMS or not?
Thanks for the review. Can you make video tips and tricks with a multimeter?
DavidTVBox DAVID I could I guess. maybe soon, I will keep this in mind!
randomtronic
Thank you, I would like to know how else to use a multimeter, except for measuring AC or DC and measuring temperature. I also found a video on which the owners reworked the multimeter for rechargeable lithium batteries from smartphones or AAA batteries with a recharging function through micro usb.
Did you try to get the RMS reading from the oscilloscope?
(5:01) - The capacitor is not a Rubicon. It's a Rubycon. Sly or what?
It is TRUE RMS. You are using a frequency with harmonics outside the bandwidth of the AN8002. Try again with 100Hz, for example.
Hi @randomtronic, my dog crashed into the wire while I was doing the measurements with the mA option, using the 600mA fuse. Soon he burned and I need to buy another. Can you PLEASE inform me of all the necessary features to buy another fuse and make the exchange? And if you know where to buy, let me know. Please :(
+José Morais have a look on ebay, as far as i remember those were 3.6mm x 10mm fuses. Look for one with the same rating, HRC type.
Thanks for reply! I search in Aliexpress and find 500mA but with another "package". I can use this, soldering in leads terminal in multimeter? If yes, I will buy... Fuse found: aliexpress.com/item/50PCS-LOT-5Values-Fast-Quick-Blow-Glass-Tube-Fuses-With-Pin-Assortment-Kit-3x10mm-0-5A/32702176964.html?spm=a2g03.10010108.1000016.1.17dfa9b4KksuyW&isOrigTitle=true
You can tell me resistence of original fuse? (if this is a problem).
+José Morais you can solder in a different package size fuse, just be careful not to short anything out. Important spec for the fuse is the rating and rupture suppression. Package not so much if you are willing to hack it in. Good luck.
Hi Chris,
unfortunately you're wrong and mislead people with your test. It is clearly stated in the manual that 8002 frequency range for AC measurements is from 40Hz to 1000Hz. Within that frequency range 8002 gives correct True RMS readings with any kind of waveform.
Be more attentive before making reviews.
rockblitz126 thanks. I agree that vid didn't go well. There is more to it to be taken into account, i will explain soon.
The square wave measurement is off because the PWM square wave is not AC, but DC.
Where i can buy small fuses to AN8001 ?
Ebay has some, just search by size (19 x 4 mm from what i remember)
I find post on the banggood they are in size 3 X 10 mm
forum.banggood.com/forum-topic-328249.html
My bad, yes, the size was 3x10.
Have a look here:
uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000006279&pageSize=25&showResults=true&aa=true&pf=110093115
Much easier to just get a Fluke or something that cannot reasonably be disputed and compare the voltages to the meter you're testing. Uni-T is bad enough but one of their cheaper models is worthless.
at the end, which to buy on aliexpress?
Чак Норис this depends on specs you want to get. Each model has different features/ranges
You are very wrong in your calculations... best meter won't help when you don't know what it measures. None of your outputs excluding a sine wave was an AC signal (it was not symmetrical to the OX axis). This meter does not have AC+DC mode. For the same reason it couln't measure frequency nor duty cycle on ACV range, for signals that do not go below 0V.
tzok83 you are correct, and i was wrong in my assumptions. Got kid of misled by the app which was calculating rms value of given signal. I am working on getting my gear back up and once ready, i will follow this video up with corrected math. Thanks!
I'm sick of buying a new multimeter becasue it has one feature that the other one does not. I've tried getting a multimeter that measures temperature and that feature works but then another one like measuring low ohms doesn't. If you follow this scheme you end up with a bunch of cheap multimeters that only partially function. The RMS function probabily works, after reading the comments, but only at a very low value, so it lacks versatility. I give this meter a pass.
test freq = too high + bad math = not accurate review. this meter is surprisingly good and accurate considering the price. this is a GREAT budget meter for the bench and hobby projects! I have two and they spit out nearly identical values. this is MORE than enough meter for even advanced hobbiests imo. the only thing I don't like it's one has a better backlight than the other (warm white vs cool bright white) and the damn backlight times out too fast and it's function is hidden behind hold function so that's annoying...but I'd buy them again in a heartbeat at $13.88 USD. Double check your testing within spec and using the right math and you'll find it's the best option out right now for a budget meter. Mind you, I'm not claiming it's an industrial meter or a full blown FLUKE but for the $$$ I think FLUKE could adjust their prices a little LOL
+MyBigThing2010 thanks. I agree with your comment. In the test i trusted the values from the app and well, there it is. I need to do a followup on this. I do like this meter, one thing annoying me is the non working functions on ac measurement (duty and freq). But it is a nice hobby meter and rms is probably within spec. Later off camera i did test with 50Hz square and got similar results - must be the ac and dc component of the signal as pointed out earlier in the comments.
You can change the backlight timing if you pull the eeprom and reprogram it (search "Hacking DTM0660L Based Multimeters" article by Kerry Wong on google).
vleeskaak thanks, sounds interesting! i will put that on my to do list ;)
vleeskaak hmmm...I'll have to check that out and see how complicated it is and if it's more trouble than its worth or not. thanks for the info!
If you have hot air to remove the eeprom and something to program it with it's actually really easy and straightforward, i recommend taking the display off while removing the chip so you don't melt the plastic holder (mine melted a bit but still works fine). In the article from Kerry Wong I mentioned has he programs it in circuit on another meter using the same chip, but I had no such luck. I didn't have anything that can program the eeproms at 3.3v and didn't want to blow out the main IC of the meter, so i tried hacking something together with a 5v arduino thing and level shifters but got nowhere. If you have some arduino thing that runs at 3.3v you might be able to do fully like the article from Kerry which would be easier soldering-wise. If you search hard on google you can also find some Russian folks have modified this meter to have extra functions (minmax/delta/etc).
If you clean the probe ends with fine steel wool and alcohol or contact cleaner it will remove whatever invisible schmutz they all seem to have, it lowers the resistance and improves the audible continuity beep. Only the really dirt cheap leads wont respond to this in my experience.
Cleaning the lead tips is a good idea, but in many cases the meter simply does not respond quickly enough, and that's due to the circuitry not the dirty lead tips
Youre right it doesnt always work-- Ive had good results but ive also got two dirt cheap meters that are so bad it just didnt make any difference-lol Cleaning is one way to find out how bad/good that part of the meter is.
I did find out that the Aneng 8009 or similar meter paired with a set of Probemaster probes makes for a very nice operating combinatiion, fast strong and clean on the beep test and less resistance when leads are shorted on the ohms scale. Of couse the Probemasters cost almost as much as the meter itself, but I dont care they work well together - I like to optimize things any way I can afford to - sometimes a nice set of leads can make a seemingly mediocre meter much better.
@@randomtronic Try it with gold plated probe tips the continuity beep will come much faster and will be fewer missed beeps.
What is the story behind that watch?
+sdm02 lol, it served me well. The straps kept falling apart every couple of years. So i had a "dummy" samsung gear watch (not working, just a case with no insides) and took the strap and base from it, then screwed my casio onto it. It worked surprisingly well and looked somewhat cool with those big screws, kind of steampunk-ish, and the watch sparked many conversations with people curious how it became to be :)
Very cool!
can i ask for the firmware please??
I have an Aneng 8008 and I think it's a bloody good little meter for what I paid for it. Absolute bargain. It's similar to this one but has a square wave generator instead of the temp range.
Looks like the RMS are really good - YOUR CALCULATIONS ARE WRONG, and the method is debatable.
If you would have measured the DC value of voltage on Arduino output, I could have said for sure.
Furthermore it is basic knowledge to know that a rectifying bridge introduces 2 junctions in series - so do the subtraction and result is spot-on...
I have one of these meters and I get much better results than these. Mine checks within specs on most ranges. I agree with other followers that your math is off. The meter is well worth the money.
i think you've got a defective meter, maybe a factory defect, handling defect coz it was shipped from china and it traveled miles away. I'd say this because i owned 1 and noticed in that meter in your hand when you switched it in frequency and percentage, there should not be a value, but in your meter there is a certain value, it should be zero.
Good multimeter I got mind for 13 dollars
got mine for same price from China. Added RANGE button. Really good small meter, the best i ever had.
I've just come from the future to track down the full story of the true-RMS meters.
its not junk like you said. its a pretty good meter
This sucker doesn't know anything. Check EEVblog post.
cool, thanks.
Nice watch
I suggest doing something you know next time.
victor vc921 is much better dmm for the same price
should have tested the Aneng AN8008
I'm not sure I agree with all of your assessments. I personally think it is exceptional value for money
So far as I can tell both the VC921 and the 8002 meters are based on the DTM0660L, which in turn appears to be so similar
to the HyconTek HY12P66 as to suggest it is the same device.
It is "true RMS" in the restricted sense of most other modern digital "true RMS" meters. If you require better accuracy true RMS then you will have to spend some serious money.
A more accurate check would be to compare a Fluke true RMS meter's reading with the readings form this device.
The only similarly priced "true RMS" meter, the VC921 has far less input protection, no current modes, and no temperature capabilities.
There is a good review of the safety and accuracy of the 8002 aka ZT102 and Aneng 8002 meter here..
ruclips.net/video/HrcxnbkkhYg/видео.html
In my opinion, this little meter is streets ahead of most of the competition in terms of robustness and safety at this price point. If anybody can suggest a better meter at even twice the price I would be keen to see if it comes close.
I have yet to get hold of one to see if I can hack on a serial port as I did with the VC921, but if I do, I'll post my results on eevblog.
www.eevblog.com/forum/testgear/hacking-the-victor-vc-921/
Yes this meter is rubbish I will not recommend to buy! One thing no one has mentioned, is the worse thing I found that it is so small and light that it falls off the bench as soon as you move the probe leads about!...You need to glue the meter on the bench to be able to test anything! .....So in reality too small of a meter is not practical!
Thanks for your big work :-)
Ncv
China product copying other china product. Wew
This guy is a joke..