Hello folks,
I noticed lately too optimistic (IMHO) bandwidth of UT-181a meter on ACV range (TRMS).
For -3dB (in comparison with 100Hz signal): sine 1.474MHz, square 1.240MHz, triangle 1.462MHz.
Incomparably larger than on any handheld Fluke?!?
Can someone explain this to me?
(Although I don't even know whether -3dB attenuation is feasible for meters, or just for filters)
frequency for -3dBV | sine | square | triangle |
UT-181a | 1.474MHz | 1.240MHz | 1.462MHz |
UT-61e | 210kHz | 211kHz | 209kHz |
Fluke 187 | 210kHz | 186kHz | 208kHz |
Fluke 289 | 200kHz | 178kHz | 199kHz |
Fluke 87V | 114kHz | 86kHz | 111kHz |
Minipa ET-997TR | 6.6kHz | 5.5kHz | 6.5kHz |
UT-210e | 2.93kHz | 2.66kHz | 2.91kHz |
I know Joeqsmith experiments and tests from some time ago, but even he cannot say that this meter lack input protection . Maybe is not like Fluke, but there is a good input protection on it .
If you will look to inside photos attached there are more MOV's and PTC in UT181A that in Fluke 289 . In fact I have seen until now 2 FLuke289 blown , and one with motherboard changed on Fluke service in Holland, but no one UT181A. Sure number of Fluke 289 sales is bigger than UNI-T 181A.
I have measure mains with UNI-T and done logging for ore than 24h and nothing bad has happened.
In fact in my experience with electronics no DMM has been damaged by such transient voltages.
Even at my beginnings (30 year ago) when I have done on cardboard a DMM with a C520D and 3 digit LCD from a slot machine (don't ask how ) nothing bad has happened . Next DMM (cheap chinese yellow 10$) and also nothing bad was happened . Those things does not have any kind of input protection on them.
I think that if you will not measure at general mains or 380 V equipments , you will not have problems. For this kinds of measurements you must use other protection class tools . Non contact recommended .
Nobody put a grill starter on a DMM inputs except @Joeqsmith .
Don't forget that this meter has passed UL and Intertek certification.
So to summarize they have a good protection input but nor for grill starters ...
If were looking for troubles I suggest putting a wire outside along a courtyard when is a storm and connect the Fluke to it . Let see how good it is ...
Hi JoeqSmith ,
It seem that you take personally every reference to your work without read carefully what is written . You are beginning to be sensible to anyone that may have doubts about "your truth " .
1. I write above, in response to idea that the UNI-T is lacks input protection which is false and you cannot deny . "They do not perform very well" doesn't mean that they lack input protection . That I am saying.
2. I believe more in engineers that design UNI-T meters than in your knowledge . At least you can design such a thing ? Or you ignorance cannot help to do this ? You think that you are more clever that they ?
3. I was not invalidate your experiments, even if they don't have a practical value for me , is your right to do and say anything you like about this domain . I am not offend by the fact that you sent to recycle bin some DMM . Keep it going. I am not considering UNI-t 181A the best DMM. For me Brymen are by far better and my 867s has better accuracy than 181A and Fluke 289. Also logging capability on 181A is nearly useless compared with Fluke 289 , even that the last is displaying graphs more slow.
So I don't have any problem to criticize my DMM's. I don't defend my purchase . Fluke 289 is also my purchase . I defend one and other I condemned ? What are you thinking ?
To sumarize, what I am saying is that UNI-T 181A doesn't lack input protection, and can be used safely in electronics . Your experiments and "grill starter characterization" are not engineering breakpoints .
Finally I am not consider @evava user a beginner that do not understand the danger of electricity . From what is doing and is said in his post I have put him in a category that can understand what I am saying and can discern by itself .
But I'm considering exaggerated opinion that this meter lack input protection . That's all , and I have exposed my opinion .
My truth?? I just collect and present data. ...
It seem that you missed the point of this thread.
You are so busy to make others to accept your opinion, that you forget how the discussion was started.
While I am not an expert I am not ignorant in ESD . My experience prove me that with some precautions measures you can avoid more troubles. But this is not a guarantee, obviously.
I was saying that UNI-T does not lack input protection. It is not on the level you test it . But as I can measure anytime in the range they specified is not a problem for me . ESD events can appear and destroy even a Fluke .
As you said you can stressed any meter to failure . So what is you point then ? Some meters are better than others . We all know .
You cannot guarantee that a Fluke, Brymen or any meter that has pass you test will not get blown if an ESD event will happened. So again what is your point ? You can guarantee that my Fluke will not be blown, because on your test it pass ?
The UNI-T can measure mains without any problems unmodified . I don't care if you are not happy with this or not .
My truth?? I just collect and present data. ...
Your ignorance is obvious .
You defend your findings . You are so identified with this so you begin a crusade against every man that even just touch your work .
Forgive me for disturbing your ego .
Forgive me that I am not granting you the importance that you deserve .
I am so sorry that I've been upsetting you Master, the keeper of all ESD knowledge in the world
Yeap ...
You have so much right dear Joe ...
It seem that you live from argues ... not a good principle of life . I'm sorry for you .
It seem that you live from argues ... not a good principle of life . I'm sorry for you .Ummm, yeah, one of you two definitely lives to argue, but it’s not joeqsmith...
(And I say this as someone who has had arguments with him.)
Hello folks,
I noticed lately too optimistic (IMHO) bandwidth of UT-181a meter on ACV range (TRMS).
For -3dB (in comparison with 100Hz signal): sine 1.474MHz, square 1.240MHz, triangle 1.462MHz.
Incomparably larger than on any handheld Fluke?!?
Can someone explain this to me?
(Although I don't even know whether -3dB attenuation is feasible for meters, or just for filters)
It seem that you live from argues ... not a good principle of life . I'm sorry for you .Ummm, yeah, one of you two definitely lives to argue, but it’s not joeqsmith...
(And I say this as someone who has had arguments with him.)So you agree with the Joeqmsith aproach , calling me ignorant , and misinterpret every sentence .
Maybe I'm wrong myself , I was try to end this discussion , but I don't know what this guy want from me .
I have argumented my post but I don't want to argument forever with a guy that do not want to understand what I am trying to say and misinterpret my words . L.E.
I will stop posting here .
(...)
While their website does show that the 181A was certified for both 61010 and 61326, it's through Intertek. The same organization that approved the 121GW that has a problem with the autorange and will not always show when possible lethal voltages are present. I hold less and less stock in these certifications as we see more shit get approved.
(...)
While their website does show that the 181A was certified for both 61010 and 61326, it's through Intertek. The same organization that approved the 121GW that has a problem with the autorange and will not always show when possible lethal voltages are present. I hold less and less stock in these certifications as we see more shit get approved.Joe, the issue may also be rooted in the spec itself - the test procedure may have been followed to the "T" by the company but it may not cover the specific scenario (or scenarios).
Not having studied the standard with the depth it deserves, I can only speculate. However, I can imagine that the cert company will better follow the standard or take the brunt of a lawsuit in case some claim is unsubstantiated.
(...)
While their website does show that the 181A was certified for both 61010 and 61326, it's through Intertek. The same organization that approved the 121GW that has a problem with the autorange and will not always show when possible lethal voltages are present. I hold less and less stock in these certifications as we see more shit get approved.Joe, the issue may also be rooted in the spec itself - the test procedure may have been followed to the "T" by the company but it may not cover the specific scenario (or scenarios).
Not having studied the standard with the depth it deserves, I can only speculate. However, I can imagine that the cert company will better follow the standard or take the brunt of a lawsuit in case some claim is unsubstantiated.
The body that governs the standards may be too large to be effective.
Take the case of magnetic interference.
If the company makes a product and knows of such a weakness but doesn't disclose it to the company doing the cert and the person assigned to run the tests does what they are told to the "T", this is what you get. I agree, the standards ARE lacking.
These guidelines are not a gold standard. The companies designing and marketing their products should be taking steps to make sure their products are safe (FMEAs, FMETs....)
They are the experts in their field.
In my case, I'm not being paid by the government or anyone for that matter.
Then again we saw where the AVE channel had dumped all over Fluke all the while showing how ignorant they were. Just crazy someone could be that dumb and claim to actually work in that industry. Then again, it created lots of views and it's obvious they didn't give a shit about the corporation they were defaming. So smarter than I give them credit for.
These guidelines are not a gold standard. The companies designing and marketing their products should be taking steps to make sure their products are safe (FMEAs, FMETs....)
They are the experts in their field.You don't go out much, do you? This is all a CYA op!
In my case, I'm not being paid by the government or anyone for that matter.I am still not convinced... (Attachment Link)
I agree, the video to me was somewhat alright while he was unsuccessfully trying to use the meter (just data), although I wouldn't jump as quickly as he did to the assumptions when trying such unconventional product for the first time. However, it quickly becomes cringy when he opens the unit (spark gap as diode, resistive network as capacitor... or something ceramic).
Joe, who are "they"? AvE?
If so, you got me confused with the gender neutral ling-o-ma-jig...