Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 52921 times)

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Offline Lightages

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #50 on: July 16, 2017, 03:11:39 PM »
You can name all the safety certificates you want (which I am all aware off).

Thank you for your permission, I was really worried I would not get it.

A very respected, smart and highly intelligent person in science and engineering with over 50 years of experience, ones told me the following (unfortunately I'm not allowed to share his name in public)

I can invent imaginary friends too, I think I had one when I was 3.

"People always say safety first. Which is very incorrect and even dangerous.
It is thinking first (just follow basic science and engineering), than safety and third is sometimes just random bad luck"

Your imaginary friend has a problem with grammar. Too bad you can't translate WTF he is saying.

In fact, it is even proven that blindly following safety protocols can even lead to potentially more dangerous situations.
You should teach people the how and why instead.

Right, knowledge prevents people from making mistakes, always.... Is this you saying this or your imaginary friend?

With me a lot of people in the field are getting extremely sick of all the ridiculous so called 'safety rules'.

Yes, safety rules only exist for those not as perfect in every way and every action as you are. I can understand why you wouldn't care as you will never and have never made an error in anything. Everyone in the past who has ever been injured or killed has been because they, and they alone, did not have the knowledge of a procedure.

You can write pages about how many years of experience you have and what kind of qualifications or certificates etc, but it all simply comes down to some general science knowledge.

Wow, sorry everyone, I should never have brought up experience and training. These must never have anything to do with reality again.

Because it simply doesn't make sense why nobody cares about batteries, while it doesn't cost much to kill someone very easily with a 9V battery!
I know companies/countries where someone isn't even allowed to handle a bloody standard knife anymore  |O :palm: :palm:
If people are to dumb to know what they are doing, they shouldn't be doing it in the first place.
In fact, in a lot of countries that's even how the law system work.

Really? How does someone know not to do something when they don't know not to do it? Certainly encouraging people to not do things they don't know sufficiently how to do properly is EXACTLY what I have been arguing. So you agree with me. You just said so. WTF are you on about then?

Which means that it's not important anymore if a product was 'unsafe', just by the fact that you were doing things you weren't qualified for cancels everything out.

 |O

Btw, with all the respect, but I don't know who brainwashed people that 'you need approved safety facilities' to test safety.
Than you simply have fallen in the big marketing trap.

Right, lets have people who don't know what they are doing or can't prove what they are doing is correct, let's have them do the testing. Wait, did you just say "If people are to dumb to know what they are doing, they shouldn't be doing it in the first place."  :palm:

You forget the reason WHY these facilities exist, with the one and only reason: cover themselves in court.
Nothing more, nothing less.

OK, now that is just totally bat shit tin foil hat time. Nothing more, wow......

That doesn't mean that other ways aren't safe.

But other methods that are unknown to be safe should not be the default, idiotic reasoning.....

(in fact I know many so called 'safety regulations' in some countries that are absolutely forbidden in others)
Second to that, if safety is so important, why is it SO difficult and SO expensive to get these tests done, of to even get the basic documents?
These things should be open to the public.

Yeah yeah, people drive on the other side of the road in some places too, idiotic reasoning....

All of this doesn't mean that there are people out there that make these type of meters, review a lot of meters or just have a very good understanding what potential dangerous there are and how to tackle them or are just smart people with enough knowledge/resources to find that out.
These meters and safety tests are not done by unknown hyper smart aliens.

And people make mistakes, don't know everything, and forget certain details. That is why we have repeatable tests for safety that are replicated  by different people who follow checklists. That is how human errors get caught.

So in fact, I would ENCOURAGE people to dig into this and share it to the public because in my opinion that's even your responsibility as an engineer/scientist.
And to add something extra for the people who have so "many experience in the field", maybe it would be better to help people out, explain it how it is done properly instead of kicking people shins.
If you can make the time and energy to rant, you can also use the same time and energy to be productive instead.
Talking about proving.......

Sorry everyone, I am being a non-productive world citizen by trying to educate. Forget all the rules everyone. I was wrong, past events, experience and the rules to save people from harm are all just smoke and mirrors and corporate lawyers. Follow the person who is tired of having to be safe. He must be right!
I am NOT a distributor for Brymen.
 

Online wilfred

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #51 on: July 16, 2017, 04:14:46 PM »
Well I ordered one for A$26. That pouch looked ideal for my scorched almonds when i'm at the opera or ballet. Scrunchy plastic bags are frowned upon you know.
 
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Offline Lightages

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #52 on: July 16, 2017, 04:32:45 PM »
To be clear, I am not bad mouthing this meter. For a bench electronics meter it seems to be a relatively good buy except for the current measurement limitations it seems to have. Except for the false CAT ratings it has I would be happy to recommend it from what I see.
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #53 on: July 16, 2017, 06:21:54 PM »
So whenever I poke at line voltage I don't take any chances. The good expensive HRC fuses have one advantage - it's less likely to blow it because you know you'll pay another $15 for new one and you are extra careful.

The fuses are there so the meter meets its CAT ratings (ie. it doesn't matter where the range selector is) but you should never need them in practice.

In practice you should double-triple check that the switch is on 'voltage' before going anywhere near the DUT.

If you're ever in a situation where a bigger fuse would mean the difference between life/death then you're doing it very wrong.
« Last Edit: July 16, 2017, 06:29:10 PM by Fungus »
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #54 on: July 16, 2017, 06:44:44 PM »
Don't fool yourself into thinking that the meter is safer for the user.
BINGO!
Doesn't make much sense to me. If you make a meter safer, then it is in fact safer.

You're failing to understand the difference between "safety" and "robustness".

You can easily make a meter more robust by adding PTCs, etc.

Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.? No amount of PTCs will save you if there's a more fundamental problem somewhere else.

If you want a 'safe' meter then buy a meter with a suitable safety rating from a trusted manufacturer.
 
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Offline kalel

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #55 on: July 16, 2017, 07:11:04 PM »
Don't fool yourself into thinking that the meter is safer for the user.
BINGO!
Doesn't make much sense to me. If you make a meter safer, then it is in fact safer.

You're failing to understand the difference between "safety" and "robustness".

You can easily make a meter more robust by adding PTCs, etc.

Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.? No amount of PTCs will save you if there's a more fundamental problem somewhere else.

If you want a 'safe' meter then buy a meter with a suitable safety rating from a trusted manufacturer.

Not being experienced, how much is the meter case itself important when it comes to safety and user (not device) protection? Probe insulation as well, I would assume.
 

Offline amspire

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #56 on: July 16, 2017, 07:25:58 PM »
Don't fool yourself into thinking that the meter is safer for the user.
BINGO!
Doesn't make much sense to me. If you make a meter safer, then it is in fact safer.

You're failing to understand the difference between "safety" and "robustness".

You can easily make a meter more robust by adding PTCs, etc.

Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.?
Yes. Why not?
 

Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #57 on: July 16, 2017, 07:58:34 PM »
Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.?
Yes. Why not?

You are going to do your own PCB layout for this $20 meter, and then remove and resolder all components including the chip-on-board main IC?! Yeah, sure...  :palm:
 

Offline amspire

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #58 on: July 16, 2017, 08:11:40 PM »
Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.?
Yes. Why not?

You are going to do your own PCB layout for this $20 meter, and then remove and resolder all components including the chip-on-board main IC?! Yeah, sure...  :palm:
No. Why would I do that? If a clearance is too small, a slot can be added, or a separator added. You make it sound like a multimeter is beyond the understanding of mortals.
 

Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #59 on: July 16, 2017, 08:27:45 PM »
If a clearance is too small, a slot can be added, or a separator added. You make it sound like a multimeter is beyond the understanding of mortals.

No, I don't. I am merely implying that those slots are not added as an afterthought, but are planned as part of the layout process. It would be a very lucky coincidence if, in an existing compact multimeter layout, you find room for slots in all places where they are needed to meet the stated CAT ratings.

Well, mill away to your heart's content. You will only be wasting $20 and a few hours of your time...
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #60 on: July 16, 2017, 09:08:27 PM »
Not being experienced, how much is the meter case itself important when it comes to safety and user (not device) protection?

Quite important. The 'explosion' is copper turning into gas inside the meter, along with a increase in volume. Fluke cases are designed to hold that in and release it slowly.

There's quite a few videos of exploding meters on youtube. I think joe's managed  burst a couple of cases, too.

 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #61 on: July 16, 2017, 09:11:27 PM »
Making it safer is a lot more difficult, eg. Are you really going to cut slots in the PCB  and/or improve the spacing between PCB traces, etc.?
Yes. Why not?

OK, go ahead. Let's hope there's nothing important on the other side of the board where you cut your slots.

Be sure to post test results.  :popcorn:

PS: Joe's actually done similar modifications to meters in his robustness thread.
 

Online BU508A

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #62 on: July 16, 2017, 09:32:05 PM »
There is no reason to buy, or, even worse, to use this meter.
It is lying about its safety specs --> getting immediatly disqualified.
End of story.
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #63 on: July 16, 2017, 09:40:27 PM »
There is no reason to buy, or, even worse, to use this meter.
It is lying about its safety specs --> getting immediatly disqualified.
End of story.

You're saying we might die if we measure a 1.5V battery with this meter?  :o

Thanks for the warning!
 

Offline ebastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #64 on: July 16, 2017, 09:41:49 PM »
There is no reason to buy, or, even worse, to use this meter.
It is lying about its safety specs --> getting immediatly disqualified.
End of story.

I don't think these categorical statements help anyone -- and they don't help your reputation on the forum either. There are obviously plenty of reasons for buying and using this multimeter, as witnessed by the thread above and also the main thread on this meter. And I am sure your post will not be the end of the story; to be witnessed by more posts below.

You are free to make the safety rating your personal top priority; but then please state it as such. For me (personally, again), having a compact backup meter with a very nice display and with low current/low voltage capability, at a very attractive price, makes this a worthwhile purchase. I will add a sticker to point out that it must not be used on mains voltages, and will be merry.
« Last Edit: July 16, 2017, 09:45:56 PM by ebastler »
 
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Online BU508A

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #65 on: July 16, 2017, 10:03:49 PM »
There is a deeper reason for this categorial statement.
It is not a problem, if this thing is used by people, which are experienced, knowing, what they are doing and do know about the limitations of such a thing.
Fine.
But, because of the poor safety design of this thing, it is more likely, that it will fail than, let's say, a Brymen 869s.
And when it fails, it could be, that it'll cause more damage, injuries etc. than the Brymen. Or a Fluke 87V.
And all this for a $20 meter?
No way.
And even, if you are knowing what you are doing, what if somebody else grabs this meter and poking around a bit?
My experience taught me, that stickers, warnings etc. will be ignored. For obscure reasons.
I'm not talking about highly trained people like engineers in this respect. I have a nephew which is very curious about
the things I'm doing and I would never excuse myself, if he's grabbing such a meter to measure stuff and he will get injured or even worse because of such a crappy meter.
The main point is: you do not have it under control anytime, anywhere.  So, the safest thing is: there is no such meter around, therefore nobody can use it.

And yes, I am aware, that there is no such thing as 100% safety. But to me it makes a differences, if a thing will fail in 1% of the cases using it or in 0.001% of the cases using it. And how it will behave, if it is failing.
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Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #66 on: July 16, 2017, 10:18:02 PM »
And all this for a $20 meter?
No way.

I have much less of a problem with this one than a $60 meter like the UT61E (for example). People buying a UT61E might think they're getting a decent meter - $60 is a lot of money.

Even worse was the $180 Uni-T bought by Dave. Even Dave thought he was getting a decent meter, but nooooo.

And even, if you are knowing what you are doing, what if somebody else grabs this meter and poking around a bit?
My experience taught me, that stickers, warnings etc. will be ignored. For obscure reasons.
I'm not talking about highly trained people like engineers in this respect. I have a nephew which is very curious about
the things I'm doing and I would never excuse myself, if he's grabbing such a meter to measure stuff and he will get injured or even worse because of such a crappy meter.
The main point is: you do not have it under control anytime, anywhere.  So, the safest thing is: there is no such meter around, therefore nobody can use it.

You're free to not buy one just like we should be free to accept the risks.

Or you could buy a gun safe for your meters.

Or ... you could try educating your nephew. When I do electronics classes I open up a DT830B and show them the blank space where the fuse was supposed to be, a $15 meter and show them the tiny fuses, and then a Fluke. The message usually sinks in.

 

Offline Rbastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #67 on: July 16, 2017, 10:18:40 PM »
There is a deeper reason for this categorial statement.
It is not a problem, if this thing is used by people, which are experienced, knowing, what they are doing and do know about the limitations of such a thing.
Fine.
But, because of the poor safety design of this thing, it is more likely, that it will fail than, let's say, a Brymen 869s.
And when it fails, it could be, that it'll cause more damage, injuries etc. than the Brymen. Or a Fluke 87V.
And all this for a $20 meter?
No way.
And even, if you are knowing what you are doing, what if somebody else grabs this meter and poking around a bit?
My experience taught me, that stickers, warnings etc. will be ignored. For obscure reasons.
I'm not talking about highly trained people like engineers in this respect. I have a nephew which is very curious about
the things I'm doing and I would never excuse myself, if he's grabbing such a meter to measure stuff and he will get injured or even worse because of such a crappy meter.
The main point is: you do not have it under control anytime, anywhere.  So, the safest thing is: there is no such meter around, therefore nobody can use it.

And yes, I am aware, that there is no such thing as 100% safety. But to me it makes a differences, if a thing will fail in 1% of the cases using it or in 0.001% of the cases using it. And how it will behave, if it is failing.

I do agree with you. Such cheap meters are quite appealing to beginners and I remember myself as a beginner using shit meters (I didn't know there were shit). When I started working on mains with power supplys etc I used those meters too.
Now I woudn't but with no other meter around or at the other side of the room, who would measure mains with it ? I strongly believe that say the good meter is across the room, even with experience youre are likely to use the cheap one you have at hands.
Now think of a newbie using such a meter not knowing the risks... I would never reccomend such a meter to a newbie, I couldn't.
Plus stickers and so on don't do shit.

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Online BU508A

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #68 on: July 16, 2017, 10:22:28 PM »
Jep. In my humble opinion safety is not alone about personal safety. It is also dedicated to circumstances and other people.
That  is one of the things I've learned since I was 12 years old and joined the voluntary fire brigade in my home village.
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Offline TheAmmoniacal

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #69 on: July 16, 2017, 10:29:12 PM »
The safety paranoia and scaremongering is getting a bit too much.. Is this what Fluke propaganda does?
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Offline Rbastler

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #70 on: July 16, 2017, 10:32:48 PM »
The safety paranoia and scaremongering is getting a bit too much.. Is this what Fluke propaganda does?

Propaganda of every safe meter.
Everybody is free to buy what they want, just don't put others in danger. I'm just giving my opinion here, agree or don't.

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Online BU508A

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #71 on: July 16, 2017, 10:43:42 PM »
Even worse was the $180 Uni-T bought by Dave. Even Dave thought he was getting a decent meter, but nooooo.

I try to avoid UNI-T meters and do not recommend them at all.

Quote
You're free to not buy one just like we should be free to accept the risks.

Yes, everyone has to decide that for himself.

Quote
Or you could buy a gun safe for your meters.

*trolling ignored*

Quote
Or ... you could try educating your nephew. When I do electronics classes I open up a DT830B and show them the blank space where the fuse was supposed to be, a $15 meter and show them the tiny fuses, and then a Fluke. The message usually sinks in.

That is exactly, what I'm doing. Educate and explain things to him. But, since he is 8 years old, I am aware, that he will not always follow the things he was taught. And for this it is better, when there is no such thing around.
“Chaos is found in greatest abundance wherever order is being sought. It always defeats order, because it is better organized.”            - Terry Pratchett -
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #72 on: July 16, 2017, 10:46:53 PM »
I doubt this meter would kill anybody on CAT II mains with any range selection.

(Anybody out there willing to sacrifice a fuse to see how eventful it would be?)

Besides, the CAT (ahem) is already out of the bag. This meter doesn't make anybody less safe in a world where Harbour Freight is giving away much worse meters for free.

 

Offline EEVblog

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #73 on: July 16, 2017, 10:47:30 PM »
Seems to be  a lot of talk about modding this meter to improve it's safety.
I don't see the point, in fact I think it's a pretty dumb idea and a waste of time.
The meter is what it is, if you buy it just live with its limitations.
If you want a safe meter for electrical work, pay double (still under $50!) and get a Fluke 101.

It's also interesting to see so much talk on Youtube comments about how supposedly spectacular this meter is and why I didn't give it thumbs up. They seem to think I've uncovered the ultimate multimeter  ::)
Fact is it's missing major current ranges, doesn't have a REL function, has tiny PITA fuses, is obviously not a meter designed for electrical work, has quite ordinary build quality (some questionable soldering in fact), and who knows what variability in manufacturing and calibration over time.
Sure it's great for compact cheapie $25 meter, but it's hardly some utopia. But people seem to be going nuts over it for some reason.
 
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Offline MK14

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #74 on: July 16, 2017, 10:54:43 PM »
Seems to be  a lot of talk about modding this meter to improve it's safety.
I don't see the point, in fact I think it's a pretty dumb idea and a waste of time.


You can read a book on brain surgery, and convince yourself that in your couple of hours of reading the book. You know almost as much as real brain surgeons do, after their 20 or 30 years experience of performing thousands of operations.

Please DON'T go and operate on someone, in your mistaken belief that it will be SAFE.

tl;dr
Huge amounts of time and resources can be spent, making things safe. It is so easy for an armchair expert, to believe that they can do it, for a millionth of the cost, and a thousandth of the time it takes.
99.999999% of the time, they are wrong.
 


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