Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 103912 times)

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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #175 on: July 18, 2017, 09:06:30 am »
While you can obviously post that the 8008 will survive to the same levels as the 8002, what proof do you have of this?

I didn't say it would fail at the exact same levels.

The OP claimed that "if ...a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up".

I find that very unlikely.

You yourself say: "I had the gun running by the time I bought that meter which is more harsh of a test than the little grill starter.  But it's pretty close to what the IEC calls for.  It's yet to damage a meter."

 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #176 on: July 18, 2017, 11:46:34 am »
While you can obviously post that the 8008 will survive to the same levels as the 8002, what proof do you have of this?

I didn't say it would fail at the exact same levels.

The OP claimed that "if ...a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up".

I find that very unlikely.

You yourself say: "I had the gun running by the time I bought that meter which is more harsh of a test than the little grill starter.  But it's pretty close to what the IEC calls for.  It's yet to damage a meter."

"(OK, that's an AN8002 but it will be the same)"  Using the word same leads me to that your claim is they fail identically.   :-//  I really have no idea.

Yes, I ran all these tests including the new gun on the 8002 but that is no indicator that the 8008 would not be damaged. OP could very well be correct.  But again, they too have no data to back it up.  We end up with peoples feelings about it rather than facts. 

I need to buy a UNI-T or get a free HF meter to show that the new gun is even doing anything.   :-DD
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #177 on: July 18, 2017, 12:09:34 pm »
Yes, I ran all these tests including the new gun on the 8002 but that is no indicator that the 8008 would not be damaged. OP could very well be correct.  But again, they too have no data to back it up.  We end up with peoples feelings about it rather than facts. 

"It's yet to damage a meter" isn't data?
 

Offline alm

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #178 on: July 18, 2017, 12:26:54 pm »
No, that is an anecdote. The plural of anecdote is not data ;).
« Last Edit: July 18, 2017, 01:06:41 pm by alm »
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #179 on: July 18, 2017, 12:47:54 pm »
No, that is an anecdote. The plural of anecdotes is not data ;).

By that reasoning you might float off into space at any moment.

 

Offline jonovid

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #180 on: July 18, 2017, 12:50:11 pm »
ANENG AN8008 DMM is ok by me! as it was tested by Dave!  unless you live in a Igloo, then the ANENG AN8002 DMM maybe 4 u.
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Offline JanJansen

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #181 on: July 18, 2017, 12:59:50 pm »
Is the true RMS accurate on this 8008 ? ( for measuring noise ), can anyone verify ?
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Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #182 on: July 18, 2017, 01:05:38 pm »
The plural of anecdotes is not data ;).

Anecdata?  ;)
 

Offline alm

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #183 on: July 18, 2017, 01:06:22 pm »
By that reasoning you might float off into space at any moment.
If our knowledge of gravity was limited to 'someone has jumped, and seemed to fall down again' then yes, I would not exclude that as a possibility.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #184 on: July 18, 2017, 01:42:27 pm »
By that reasoning you might float off into space at any moment.
If our knowledge of gravity was limited to 'someone has jumped, and seemed to fall down again' then yes, I would not exclude that as a possibility.

But if ten million people jumped and they all fell down again than you could use that result to make predictions without being branded a dangerous lunatic, right?
 

Offline alm

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #185 on: July 18, 2017, 02:07:04 pm »
But if ten million people jumped and they all fell down again than you could use that result to make predictions without being branded a dangerous lunatic, right?
What if I was a professional athlete (high jumper)? Without knowing the energy they used, I can not be sure what the limits are. Maybe they were 10 million children? And any reasonably fit adult will be able to jump to the moon?

How many meters have you tested or have seen reports of being tested? What were the test conditions like? I would describe the difference between anecdotes and data as a well documented, reproducible procedure and a structured way of collection. If ten people said 'I measured resistance in auto-ranging mode across a full 9V alkaline battery brand X', and subsequently report if it failed or survived, then that would be data. Not necessarily data that would convince me that it would survive the same with higher voltages, but it would be data.

Saying 'I have not seen any reports' could be subject to a selection bias (are the people posting a representative sample of AN8008 customers? are people more likely to report success or failure?) and is very vague (how many people? what did they expose the meter to? what is their mains voltage? was the environment likely to trigger ESD?).
 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #186 on: July 18, 2017, 02:11:56 pm »
If ten people said 'I measured resistance in auto-ranging mode across a full 9V alkaline battery brand X', and subsequently report if it failed or survived, then that would be data.

But when joe says, "It's yet to damage a meter", it isn't?

Got it.

OK, what if we took joe's actual results:
Code: [Select]
Pass
Pass
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Pass
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What would that be called?  :popcorn:

What predictions could you make about an unknown, randomly chosen meter using that information?


How many meters have you tested or have seen reports of being tested? What were the test conditions like?

https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/
« Last Edit: July 18, 2017, 02:27:50 pm by Fungus »
 

Offline alm

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #187 on: July 18, 2017, 03:02:17 pm »
OK, what if we took joe's actual results:
[snip]
What would that be called?  :popcorn:

What predictions could you make about an unknown, randomly chosen meter using that information?
Joe's result (including his documentation about his test setup and the actual meter models) would definitely be data. Using this to predict another random meter is tricky. If we assume that the group Joe tested is representative for the group we pick the random meter from, I would say that the meter has an expected pass chance of 38/43th. However, if Joe only ever tested Fluke meters which are the definition of perfection (;)), and now started tested $5 meters, that expectation may be way off.

You might be able to improve the estimate if you split the results by manufacturer or price class. How many of the meters that Joe tested with the current procedure were around the $20 mark? And even then, you can only figure out an expected pass chance. A meter that is 90% likely to pass a test can still fail.

If Joe is not comfortable in extrapolating the data to an untested meter, then I would not extrapolate the data either.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #188 on: July 18, 2017, 03:05:21 pm »
However, if Joe only ever tested Fluke meters which are the definition of perfection (;)), and now started tested $5 meters, that expectation may be way off.

Really? The Fluke 87V failed a test that this meter's $15 sibling passed.

FWIW, here are the PCBs of the two meters in question (AN8002 and AN8008).


Me? I've got $10 that says the AN8008 will pass the sparker test.


PS: Is that a Rubycon capacitor?
« Last Edit: July 18, 2017, 03:08:11 pm by Fungus »
 

Offline rsjsouza

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #189 on: July 18, 2017, 03:33:44 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #190 on: July 18, 2017, 04:00:07 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).

Join the club :-)

Edit: I just noticed they ship them without battery   :(

I need to order a '23A', 12V battery as well.
« Last Edit: July 18, 2017, 04:37:09 pm by Fungus »
 
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Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #191 on: July 18, 2017, 04:00:22 pm »
I went for its mini-me version and the cable accessory set.

Hmm, they actually state that the insulation on those test leads is silicone! Curious to see what I will get with my meter when it arrives. But then, they also claim the meter to be CAT II 1000V rated...
 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #192 on: July 18, 2017, 05:18:58 pm »
But when joe says, "It's yet to damage a meter", it isn't?

Got it.

OK, what if we took joe's actual results:
Code: [Select]
Pass
Pass
Pass
Pass
Pass
Fail

I believe there is some confusion that I am partly to blame for.  If you go back and read my comments about not damaging a meter yet, these refer to the new homemade ESD gun, not the piezo ignitor.   While both devices put out a fairly fast transient, if you followed along when I tested the 181A and later was working on the new gun, you are aware that the gun can supply much higher current levels than the piezo. 

The data that you present I assume came from my spreadsheet and you just missed on meter in the beginning.   This data is for the piezo ignitor, not the new gun.   To avoid this confusion, I have added a new column to the spreadsheet for the new gun.

I had planned to stop using the piezo ignitor but people have requested that I leave it in.  I think this stems partly from my comments about how no meter should ever be damaged by it and that we have seen so many UNI-Ts fail this test.   It's pretty much what I consider to be the least stressful test I have ran on the meters.

OK, what if we took joe's actual results:
[snip]
What would that be called?  :popcorn:

What predictions could you make about an unknown, randomly chosen meter using that information?
Joe's result (including his documentation about his test setup and the actual meter models) would definitely be data. Using this to predict another random meter is tricky. If we assume that the group Joe tested is representative for the group we pick the random meter from, I would say that the meter has an expected pass chance of 38/43th. However, if Joe only ever tested Fluke meters which are the definition of perfection (;)), and now started tested $5 meters, that expectation may be way off.

You might be able to improve the estimate if you split the results by manufacturer or price class. How many of the meters that Joe tested with the current procedure were around the $20 mark? And even then, you can only figure out an expected pass chance. A meter that is 90% likely to pass a test can still fail.

If Joe is not comfortable in extrapolating the data to an untested meter, then I would not extrapolate the data either.

I agree.  Even if we are all talking about the piezo and not the new gun the sample size is just too small to say much about all meters available.  Even if I had ran more brands and models, just from the little testing I have done, I would be VERY hesitant to extrapolate how new meters would perform.     

Considering that 3 or the 5 meters that failed the piezo test were UNI-Ts, I fully agree that splitting the results would improve the estimate.  Still my confidence factor would be poor.   

However, if Joe only ever tested Fluke meters which are the definition of perfection (;)), and now started tested $5 meters, that expectation may be way off.

Really? The Fluke 87V failed a test that this meter's $15 sibling passed.

FWIW, here are the PCBs of the two meters in question (AN8002 and AN8008).

Me? I've got $10 that says the AN8008 will pass the sparker test.
PS: Is that a Rubycon capacitor?

I agree that the 87V is really a flyer (outside the norm) from what I have seen with Fluke.   Similar to the UNI-T 139c that actually fairs well in my tests compared with the vast majority of UNI-T DVMs I have looked at.    I wonder if the new gun would damage one..  Anyway, this is exactly why even within a brand, I would be hesitant to comment about how an untested meter would perform. 

If you now understand that there are two different ESD tests, one with the piezo grill ignitor and one with the new gun, what are you considering the "sparker test"?   

ESD is a fun one to design for.  There's a fair difference between the two PCBs you show. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline metrologist

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #193 on: July 18, 2017, 05:31:18 pm »
I do not think you can extrapolate Joe's tests to any other model meter, even within the same price class, brand, or even model series (as the Fluke 87V seems to show). A data point of one?

I like Joe's video format and editing. I think 20% more could be shaved off, with double your time  :-DD. I like it, to the point  :-+

"There's a fair difference between the two PCBs you show." Just one small change would seem to have the potential to make or break the result. Maybe even the angle of how a component is placed in the exact same model?
 

Offline rsjsouza

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #194 on: July 18, 2017, 05:37:52 pm »
I went for its mini-me version and the cable accessory set.

Hmm, they actually state that the insulation on those test leads is silicone! Curious to see what I will get with my meter when it arrives. But then, they also claim the meter to be CAT II 1000V rated...
That is why I chose to pay a bit more extra (about $0.50) when compared to a few other sellers that did not mention silicone on the description.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #195 on: July 18, 2017, 05:55:04 pm »
If you now understand that there are two different ESD tests, one with the piezo grill ignitor and one with the new gun, what are you considering the "sparker test"?

Either will do, but I think you should keep doing with the grill igniter simply because it's become a de-facto yardstick. It's difficult to compare new/old results if we switch to something else.

Do those igniters wear out with time? It might be good to measure the sparks and make sure it's holding up, producing sparks just like the first day.

There's a fair difference between the two PCBs you show.

They've moved the buzzer and a few components around, yes.

When you really zapped the AN8002 the major trace damage happened around the area of the buzzer. Maybe they moved the buzzer away to improve that area of the PCB.  :popcorn:



Regardless, the thing that failed first on that meter was the transistor clamp - nothing to do with PCB spacing or layout. If the transistors in the AN8008 are the same then I'd guess it will fail in the same way.
« Last Edit: July 18, 2017, 06:35:57 pm by Fungus »
 

Offline Lightages

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #196 on: July 18, 2017, 06:47:08 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).

I see no CAT ratings claimed i the ad for that meter. If it has no claim of safety, it looks like a cool little meter for the beginning hobbyist to have for his/her low energy experiments. That is, if can be reliable for such a cheap price.
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #197 on: July 18, 2017, 06:56:24 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).

I see no CAT ratings claimed i the ad for that meter. If it has no claim of safety, it looks like a cool little meter for the beginning hobbyist to have for his/her low energy experiments. That is, if can be reliable for such a cheap price.

I have no idea if they are using different chips and if one is better, but I would think it would at least be as reliable as a DT830. Looking at the image, maybe the input jacks are even placed better (directly on the PCB) and may last longer if probes are moved around often. That said, I can't say which of the really low end meters (e.g. sub $6) offer best value. This one is the smallest and offers battery measurement, some offer temperature measurement, some offer a backlight but no battery or temperature measurement, and which is safer... who knows. :)

Is there something that should/could be added here?

 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #198 on: July 18, 2017, 07:04:22 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).

I see no CAT ratings claimed i the ad for that meter. If it has no claim of safety, it looks like a cool little meter for the beginning hobbyist to have for his/her low energy experiments. That is, if can be reliable for such a cheap price.

Correct. No false CAT labels, just a tiny meter.

Case looks decent. The PCB looks OK in the pics. I like that the amps ranges are on a separate input jack. Looks to have a decent battery tester. It has a continuity buzzer, unlike most DT830Bs. Buzzer is mounted on a nice little holder. Looks calibratable (although that works both ways - it will likely drift more with that cheapass pot)

And .... it's TINY:popcorn:



I hope there's plenty of solder on the other side of the board to hold the input jacks in place.


« Last Edit: July 18, 2017, 07:33:23 pm by Fungus »
 
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Offline rsjsouza

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #199 on: July 18, 2017, 07:10:13 pm »
See what you guys did? All this chat about Aneng made me curious about their gear.  :-DMM

My hobby capex of this month wouldn't allow for an 8008, thus I went for its mini-me version and the cable accessory set. Everything less than US$9.00 with ePacket shipping (with tracking #).

I see no CAT ratings claimed i the ad for that meter. If it has no claim of safety, it looks like a cool little meter for the beginning hobbyist to have for his/her low energy experiments. That is, if can be reliable for such a cheap price.
I like this fact as well and bought it for the curiosity. If its interior is as clean as the one shown in the photograph, I would consider it a bonus (it's been a while since the Harbor Freight DT830s were clean inside).


What happened? Hopefully no hurt feelings were involved between the parties...
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 


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