Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 164686 times)

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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #150 on: July 17, 2017, 11:16:37 am »
My humble guess is that only a very few of you are legally allowed to touch anything that will require a multimeter with a CAT-rating.

Well:
a) A 1.5V battery has a CAT rating.
b) Nobody needs a license to open up a power supply or anything else that plugs into a mains socket. That's CAT II (or even CAT III) right there.
 

Offline WackyGerman

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #151 on: July 17, 2017, 11:34:51 am »
My humble guess is that only a very few of you are legally allowed to touch anything that will require a multimeter with a CAT-rating.

Well:
a) A 1.5V battery has a CAT rating.
b) Nobody needs a license to open up a power supply or anything else that plugs into a mains socket. That's CAT II (or even CAT III) right there.

You can open it up and measure at your own risk . But if something badly happens like a fire it will bring you to the justice
 

Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #152 on: July 17, 2017, 11:37:15 am »
Appreciate your input joe, all read!  ;) Big fan of your robustness testing videos.


Yet more suggestions for meters to test in the future: Chauvin Arnoux MTX 32xx or any of the clamshell style ones (another major European manufacturer akin to Gossen)

I think someone else asked me about one of these some time ago.  Maybe that was you.  I looked for a distributor.  There is very little info on them.  A little advice, invoking the Gossen brand as a comparison is not a good way to sell me on a product.  It will take some time to get the bad taste out of my mouth over that ordeal.   Who knows, maybe they are actually doing something on their end.   

Why do you call it a clamshell?  I would assume it folds up based on this.    Looking over their products, I think if I were to buy one, it would be the OX 5042.  Of course when I go to the following and select the Technical document, I get 404Not Found.  Giving me lots of confidence in them from the start.

http://www.handscope.chauvin-arnoux.com/en/documents/publications.aspx


       

Looks like I'm too late, the clamshell style meters (attached below) are listed as discontinued most places. Always been curious how the input protection looks like in those (and performs). Now replaced with MTX 3290.

Compared with Gossen because I suspect a similar ordeal, but isn't that just fun?  ;D

EDIT: In the US it seems to go by the model AEMC 2125.75,  still sold by AEMC on Amazon https://www.amazon.com/AEMC-2125-75-Multimeters-000-count-Graphical/dp/B00A8P6GOG

« Last Edit: July 17, 2017, 11:50:15 am by TheAmmoniacal »
 

Online ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #153 on: July 17, 2017, 12:00:20 pm »
Well it is another cheapy crappy multimeter which doesn t meet the safety regulations and labelled with the wrong CAT rating . It s built down to the price with shitty input jacks , tiny little fuses and no input protection . It s not worth the money because it will not lasting a long time , it is dangerous to use because the uA range shares the same jack with voltage ranges . Don t buy this shit , it s a waste of money .

You may not want to buy it, but please refrain from telling me what to do.

I own a very nice set of jeweler's screwdrivers. They are very precise and handy to use. And, believe it or not, I do not use them to work on mains outlets, although those screwdrivers do not even bear a warning label cautioning me against that use. -- Horses for courses, and that is how I intend to use the AN8008 and my other meters as well.

By the way, for even more credibility, I recommend to cut back on the use of swear words and to omit the spaces before punctuation marks.
 
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Offline JanJansen

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #154 on: July 17, 2017, 12:05:17 pm »
It s not worth the money because it will not lasting a long time.

How do you know ?
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Offline WackyGerman

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #155 on: July 17, 2017, 12:17:56 pm »
Just look at the input jacks . They are not fitted properly and if you put in a plug you will push in the input jack and stress the solder joint of it on the board and it will break soon . The second problem is the lack of input protection . If a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up
 
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Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #156 on: July 17, 2017, 12:23:35 pm »
Just look at the input jacks . They are not fitted properly and if you put in a plug you will push in the input jack and stress the solder joint of it on the board and it will break soon . The second problem is the lack of input protection . If a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up

The first actually happened to a DT830 to me. It's not the solder joint that cracked though, it was the input jack metal holder part (not sure what it's called), somewhere in the middle (between the input jack and solder joint). I'm not sure if replacement parts can be purchased.
« Last Edit: July 17, 2017, 12:26:59 pm by kalel »
 

Offline WackyGerman

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #157 on: July 17, 2017, 12:49:04 pm »
Oh that s even worse . A broken solder joint could be repaired but the input jack itself not . I don t think that you could buy spare parts for cheap multimeters , it would be too expensive for the manufacturer to keep them on stock . Anyway it would drive me nuts to repair the multimeter often before using it  :scared:
In my opinion good input jacks are an important point when buying a multimeter
 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #158 on: July 17, 2017, 12:50:57 pm »
Just look at the input jacks . They are not fitted properly and if you put in a plug you will push in the input jack and stress the solder joint of it on the board and it will break soon .

Not if they're properly supported by the back of the case.

Which they are:


(OK, that's an AN8002 but it will be the same)

The second problem is the lack of input protection . If a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up

Nope. These have been tested with joe's sparker and survived perfectly.



That one didn't fail until 3000V.

I think Everybody here knows that these meters aren't good for working with 230V AC. There are plenty of warnings in the video. For working with 5V, 12V, Arduinos, etc., they're fine.
« Last Edit: July 17, 2017, 01:18:56 pm by Fungus »
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #159 on: July 17, 2017, 01:52:10 pm »
I think Everybody here knows that these meters aren't good for working with 230V AC. There are plenty of warnings in the video. For working with 5V, 12V, Arduinos, etc., they're fine.

I learned a bit in this thread. In fact, I didn't know how dangerous (not whether or not, just how much) it was to use a multimeter on mains (although anything with mains always gets people careful with reason). I'm just not sure how it compares to other "cheap methods" such as those 'dangerous voltage detecting screwdrivers' (I guess you know what I mean). Non contact ones should be safe, but are not always dependable. I'm sure people use both in practice, as anything is safer than using your hand (or worse, both hands) to check if there's voltage or not.

Videos from Fluke and Joe and others can be helpful to see some of the dangers with some meters (e.g. Fluke exploding the DT830). Although, I have yet to learn how many of it applies to using the meter on proper range (voltage range), in which case I assume other protections come into play (case, probes, etc), and not e.g. which fuse is used. Of course, I need to watch a bit more and I'm sure I'll find out. :) As far as measuring mains current, if needed for some reason, seems safer with a clamp meter (plus, no need to cut a wire), as even a cheap clamp meter you're not connecting to the circuit.

I still like that there are cheap meters that can measure current, like the DT830, since it's quite useful for testing LEDs and other safe but interesting projects. It's always helpful to know the current, and some meters that can do both at the same time (e.g. USB power meters) can be very useful too. A meter like AN8002 or 8008 both seem to offer great advantages. Things like more accuracy (more or less important), capacitance, frequency, temperature (8002) all add a lot of functionality even for true beginners (on this forum, I think that sometimes a beginner could mean a knowledgeable, experienced person, or someone without too much experience that has finished formal EE education or such).
« Last Edit: July 17, 2017, 01:58:10 pm by kalel »
 

Offline Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #160 on: July 17, 2017, 02:18:59 pm »
Testing these meters is a bit like crash testing cars, various models will perform better than others. Its really a question of what the person can afford and also of course what they are going to be used for. For the general hobbyist working with electronics I would say that most are perfectly suitable as you do not generally at that level of involvement come across large amounts of energy.

If however you were using these professionally as a matter of course then you should always get the very best you can, weighing up all the factors such as is it going to be bench kept, chucked in a toolbox and used away from the bench, is it going to be used on high energy sources or just checking voltages etc on low power electronics etc, it all will have a bearing.

So basically at the end of day, until there are proper standards testing and better ways of enforcing them, common sense must prevail. If we ever get to the position of having better standards enforcement, then the cost of the better meters will drop dramatically because of the scale of economies will come into play for things like HRC fuses etc. that will benefit everyone.
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Offline madires

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #161 on: July 17, 2017, 02:23:56 pm »
FYI, a sparky uses something like a Duspol for mains, and not a DMM. I think it's amazing how much value you get with the AN8008. The missing delta function and the lack of mA ranges is disappointing, but acceptable for that price. And regarding the poor input protection, I've had much more expensive DMMs with worse input protection.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #162 on: July 17, 2017, 02:43:17 pm »
Videos from Fluke and Joe and others can be helpful to see some of the dangers with some meters (e.g. Fluke exploding the DT830). Although, I have yet to learn how many of it applies to using the meter on proper range (voltage range)

Even the crappy meter in the Fluke video was OK on the proper volts range. It only exploded when he switched to a 'bad' range.

(but I'd be very unhappy holding one in my hand with 466V high energy AC going through it...  :scared: )

« Last Edit: July 17, 2017, 03:10:03 pm by Fungus »
 

Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #163 on: July 17, 2017, 03:31:44 pm »
I would love to see someone replicate Fluke's demonstration, 750 VAC high-current capable supply with the meter in 200 ohms range.
 

Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #164 on: July 17, 2017, 03:41:55 pm »
I would love to see someone replicate Fluke's demonstration, 750 VAC high-current capable supply with the meter in 200 ohms range.

There's also a few different PCBs with different DT830 models. I'd be interested if those variations make things more or less spectacular. On the other hand, I doubt someone would recreate such a supply just to test some DT's. :)

Edit, maybe you meant AN8008 instead. Not that it changes things in terms of that being a costly and probably not very safe thing to have.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #165 on: July 17, 2017, 04:00:10 pm »
I would love to see someone replicate Fluke's demonstration, 750 VAC high-current capable supply with the meter in 200 ohms range.
There's also a few different PCBs with different DT830 models. I'd be interested if those variations make things more or less spectacular.

Yep.

Even with the exact same model/batch it might not go exactly the same way due to variations in the probes, the soldering, etc.

On the other hand, I doubt someone would recreate such a supply just to test some DT's. :)

I bet Youtube disagrees with you.  :popcorn:

Edit:

« Last Edit: July 17, 2017, 04:03:07 pm by Fungus »
 
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Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #166 on: July 17, 2017, 04:04:04 pm »
I can only do 300 mA at 750 AC, but my smoke detector is wired in parallel with the whole building and alerts the fire department  :(
 

Offline tronde

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #167 on: July 17, 2017, 04:34:39 pm »
People make a lot of noise about false CAT-ratings. Why don't the same people make a lot of noise about what really matters when it comes to electrical safety?

Most countries around the world have a lot of legal regulations about education and long-time experience specifying what kind of work you are allowed to do on almost ANY kind of electrical equipment or wiring.

My humble guess is that only a very few of you are legally allowed to touch anything that will require a multimeter with a CAT-rating.

This is rather beside the point and this argument is without merit, but I am going to respond because it is also completely wrong.
 
That certainly isn't true in the US, and I don't believe it is true most places in the world.  I don't know about Norway -- maybe all the stories about the excessive regulations are true, but your description isn't true in most of the rest of Europe either.  In the US you can't operate as a professional electrician without a license, but you can do almost anything in your own house that doesn't require a building permit.  I know this isn't true everywhere, but I don't believe most places are nearly as strict as you suggest.  In most of the US that means that you can pull new circuits from the main breaker panel.  Even if you can't, you can repair existing wiring, and you can certainly measure it with a voltmeter even if you don't change anything (for instance to diagnose a problem for which you might hire an electrician to fix.

And pretty much all of the regulation that does exist stops at the wall outlet.  There is basically zero restriction on who can work on a mains powered electrical appliance.  Anyone can (legally) replace a worn power cord or troubleshoot a line operated power supply.  Of course in the CAT rating system that is only a CAT-II environment, but it is still a situation where you want a meter that is not adding any danger -- and meters with deceptive labeling are definitely something worth being upset about, even if they are totally functional for low voltage applications.

Likewise, there is no restriction (in the US) on who can work on high voltages that are not part of the power distribution system.  I have in the past worked on high voltage power supplies capable of generating from hundreds to thousands of volts.  They don't have the same power behind them as a main distribution panel, but you can still have quite a bit of energy stored in a capacitor.  There is zero certifications, regulations, or licenses for who can do that in the US.  Other countries do have mandatory engineering licenses to be a professional electronics engineer, but in most places that is only required if you are doing so professionally.  And again, it doesn't exist in the US.  There is absolutely reasons for hobbyists to have safely designed meters, even if they are not doing the specific things that the cat rating is designed for (i.e., working on power distribution networks).

I do sort of agree that many people make too big of a deal about it, as if there is no value to a meter without CAT-4 600V ratings.  There are plenty of uses for multimeters that are never anywhere near a high power / high voltage circuit. The majority of electronics hobbyists would be well served by a safety-low voltage meter, or at most one that honestly meets CATII-300V, and the features this little $25 meter has that make it attractive: high resolution and low ranges are specifically things that don't require high voltage surge capability.

What I know, is that the Norwegian regulations for electrical wiring and safety are harmonized as much as possible with the EU regulations.

Here an "amateur" is allowed to change 2-pole plugs with or without PE on equipment wires meant for no more than 25A, simple repair of small table lamps with flexible wires, connect a lamp hanging in a hook to the wiring if the connection is not considered a permanent part of the installation.

Equipment fed from no more than 50V is allowed given maximum power consumption is no more than 200VA, connection to mains is via wall socket, and the user instructions are strictly followed. I.e. no diy equipment.

All kind of repair is covered by specific regulations regarding education and work experience.

I have seen similar descriptions from other European countries as well, so I guess diy is more limited than many people are aware of. The Norwegian regulation refer to EU-directive 2005/36/EC.

Norwegian regulation (in Norwegian)
https://lovdata.no/dokument/SF/forskrift/2013-06-19-739

 

Offline b_force

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #168 on: July 17, 2017, 07:04:04 pm »
I won't bother replying to your rather emotional response. I will let it stand by itself.

Edit:
If anyone can show me where I call people names, or attack people personally instead of the ideas presented, I will apologize immediately.


Since you can't manage to read your own text, I will paste it here "More idiotic reasoning."

Is that reasoning I am attacking, or the person? You are applying idiotic reasoning. I will not apologize for attacking poor reasoning. I am responding only because I respect the opinions of others and assume that idiotic reasoning can be corrected. I also correct my own idiotic reasoning regularly.

If I assume that idiotic reasoning cannot be corrected because the other person is beyond help, I don't bother trying.
The fact that you mention peoples grammar (while they are not being native) and call peoples friends/technical contacts are imaginary says enough.
Pretty disrespectful.

Just only saying that safety rules are holy as the holiest god is just lack of any reasoning at all.
(and you also clearly don't have a clue about any international regulations and how different they are)
That way we would still living in caves.

Anyway, not worth putting energy into this.
I would say to the rest go on and try to help each other with new ideas.
Like I said before it's not productive and only gives a very negative vibe to all of this.

Offline free_electron

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #169 on: July 17, 2017, 08:02:42 pm »
Just bought two of em. Don't give a flying F about Cat rating. i don't do anything above 12 volt and 1 ampere anyway. if i do : i have flukes and agilents.
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Offline Specmaster

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #170 on: July 17, 2017, 08:07:04 pm »
Well it is another cheapy crappy multimeter which doesn t meet the safety regulations and labelled with the wrong CAT rating . It s built down to the price with shitty input jacks , tiny little fuses and no input protection . It s not worth the money because it will not lasting a long time , it is dangerous to use because the uA range shares the same jack with voltage ranges . Don t buy this shit , it s a waste of money .

You may not want to buy it, but please refrain from telling me what to do.

I own a very nice set of jeweler's screwdrivers. They are very precise and handy to use. And, believe it or not, I do not use them to work on mains outlets, although those screwdrivers do not even bear a warning label cautioning me against that use. -- Horses for courses, and that is how I intend to use the AN8008 and my other meters as well.

By the way, for even more credibility, I recommend to cut back on the use of swear words and to omit the spaces before punctuation marks.
Nicely put, at the end of the day you would have to be a complete and utter dummy not to understand the differences between something costing £20 and something that costs £500, especially when they both purport at least in the main part of say volts, current and resistance, to do the same thing and probably with similar ratings. Clearly the cost differences are not just down to things like the accuracy of them and anyone buying a cheaper meter must comprehend that corners have been cut in order to meet the price point.

It cannot be that difficult either to design and produce something that would for all but the very worst conditions, contain all blast, fireball and debris etc within the case with reasonable overload protection to protect against accidental minor overloads, without pushing the price too high?

I very much doubt if any of the famous Simpson or the Avo meters would withstand the energy levels that those meters were exposed to but are we all going to stop using them now? Of course not.
« Last Edit: July 17, 2017, 08:09:26 pm by Specmaster »
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Offline Electro Detective

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #171 on: July 17, 2017, 11:04:17 pm »
FYI, a sparky uses something like a Duspol for mains, and not a DMM. I think it's amazing how much value you get with the AN8008. The missing delta function and the lack of mA ranges is disappointing, but acceptable for that price. And regarding the poor input protection, I've had much more expensive DMMs with worse input protection.

Sorry mate, can't buy that  ::)

The sparkies over there are either not making money to also afford a proper CAT class DMM to do their job better informed and verified,

or not aware of its abilities perhaps ?   :-//

A 'Duspol' for all the viewers here btw is a dual probe contact voltage/continuity tester,
and anyone playing with electrics should own a good one..or two if you enjoy life and prefer to avoid hospitals and funeral parlors,
relying on just one Duspol and the condition of the batteries

www.benning.de/duspol-voltage-testers-en.html

www.fluke.com/fluke/uken/electrical-testers/Electrical-Testers/T90-T110-T130-T150-Voltage-and-Continuity-Testers.htm?PID=73757


Let's cross fingers the sparkies over there get an insulation tester, gloves and eye protection before their final Birthday or Christmas    :-+

 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #172 on: July 18, 2017, 12:20:37 am »
Of course when I go to the following and select the Technical document, I get 404Not Found.  Giving me lots of confidence in them from the start.

I did find this: (in French, though)

http://www.handscope.chauvin-arnoux.com/Portals/0/pdf/DT_Handscope_Ed01_FR.pdf

I assumed for CAT III 600 it would be certified but appears it's not.  No manuals on-line that I could find.   They don't appear to have an Amazon store.   Seems more effort than it's worth at this time. 

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #173 on: July 18, 2017, 12:26:50 am »
Appreciate your input joe, all read!  ;) Big fan of your robustness testing videos.


Yet more suggestions for meters to test in the future: Chauvin Arnoux MTX 32xx or any of the clamshell style ones (another major European manufacturer akin to Gossen)

I think someone else asked me about one of these some time ago.  Maybe that was you.  I looked for a distributor.  There is very little info on them.  A little advice, invoking the Gossen brand as a comparison is not a good way to sell me on a product.  It will take some time to get the bad taste out of my mouth over that ordeal.   Who knows, maybe they are actually doing something on their end.   

Why do you call it a clamshell?  I would assume it folds up based on this.    Looking over their products, I think if I were to buy one, it would be the OX 5042.  Of course when I go to the following and select the Technical document, I get 404Not Found.  Giving me lots of confidence in them from the start.

http://www.handscope.chauvin-arnoux.com/en/documents/publications.aspx


       

Looks like I'm too late, the clamshell style meters (attached below) are listed as discontinued most places. Always been curious how the input protection looks like in those (and performs). Now replaced with MTX 3290.

Compared with Gossen because I suspect a similar ordeal, but isn't that just fun?  ;D

EDIT: In the US it seems to go by the model AEMC 2125.75,  still sold by AEMC on Amazon https://www.amazon.com/AEMC-2125-75-Multimeters-000-count-Graphical/dp/B00A8P6GOG

One strange looking meter.    One review: "Nice but quirky meter."  I don't see the appeal.   

Offline joeqsmith

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #174 on: July 18, 2017, 01:06:56 am »
...
(OK, that's an AN8002 but it will be the same)
The second problem is the lack of input protection . If a little static discharge goes into the multimeter or you accidently took the wrong function the ic will blow up

(OK, that's an AN8002 but it will be the same)

Nope. These have been tested with joe's sparker and survived perfectly.
...
That one didn't fail until 3000V.
...

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.   I was impressed with how well the 8002 held up.  3KV, it's double what that 87V failed at and with just a PTC and a couple of diodes. These transients are applied to every mode the meters has except the ones that are related to current measurement.   

Of course someone is bound to think that means it would survive being hooked to the 2KV secondary of their MOT because after all, 2KV is a KV less than 3KV.  Plenty of head room.   It won't be.  The MOT will win the battle.   And we can't forget about the special ones that claim I am driving DC into the meters or directly coupling capacitors to them so when they fail it's because I exceeded the 600V the meter was rated to.    The 3KV transient that the 8002 was subjected to is the same transient I have applied to the last 40 or so meters, many of which have survived.   If you want a more robust meter, they are out there. 


While you can obviously post that the 8008 will survive to the same levels as the 8002, what proof do you have of this?   Consider when I ran the Amprobe AM530.  It was not near as robust at that lower priced AM510.   The 87V was no where near as robust as every other Fluke I have looked at.  At least it was reparable.  The vast majority are not.   Anyway, rather than post what you claim as fact based on your feelings, IMO it's better to run the tests and let the data stand on it's own or add a qualifier to your statements.  "My guess is the 8008 would be as robust as the 8002 because ....."  People would then know you really don't know and not take it as fact.  Or, post the data you have to prove it.    Sorry for the rant.       
 
The following users thanked this post: drussell, BU508A


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