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Author Topic: EEVblog #1007 - Is a $25 Multimeter Any Good  (Read 41714 times)

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Offline floobydust

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #450 on: September 17, 2017, 08:28:12 AM »
I have been contacted by  Zotek who claim to be the original designer and manufacturer of the AN8008

What did they say?  :popcorn:

They want to pay me to review their new product  ::)

It seems like a way to get marketing and product exposure.
The fake 61010 claims and poor quality make me ask, how low to go.
Oh wow 10,000 counts and the the rotary switch oxidizes after a couple weeks  :-DD
It's like cheap candy. After the sugar buzz, you faint.

Get a box of them for joeqsmith ;)
 

Online xavier60

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #451 on: September 18, 2017, 06:57:30 PM »
I received a reply from Zotek about the dead spot issue on the millivolt range.
"Thank you for your support to our products. ZT109 can measure voltage larger than 20uV."
This indicates to me that the ZT109 has a +/-20uv dead spot. This would bother me.

« Last Edit: September 18, 2017, 07:00:03 PM by xavier60 »
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #452 on: September 18, 2017, 10:12:17 PM »
This indicates to me that the ZT109 has a +/-20uv dead spot. This would bother me.

You buy a $20 meter then can't sleep at night because it has a +/-20uv dead spot? Schadenfreude.
 

Online xavier60

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #453 on: September 18, 2017, 10:20:02 PM »
This indicates to me that the ZT109 has a +/-20uv dead spot. This would bother me.

You buy a $20 meter then can't sleep at night because it has a +/-20uv dead spot? Schadenfreude.
I didn't buy that meter. The meter I did buy, the AN8008, has a +/-5uv dead spot. This isn't a practical problem for what I use it for.
A +/-20uv dead spot could be a problem for what I use the meter for.
The dead spot has been intentionally programmed into the meter.
« Last Edit: September 18, 2017, 10:43:37 PM by xavier60 »
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm
 

Offline floobydust

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #454 on: September 19, 2017, 03:17:10 AM »
The uV deadband seems to be about the DMM IC's quality.

A/D converter and input amp noise, and offset limit the bottom end. Then there is the reference noise also affecting the measurement low end.
The HY12P65 datasheet best is 10uV offset and 2uV noise but some people say the chip-on-board package is lower quality compared to the QFP packaged part.
COB noise is worse, and noise-ranked parts are out there.

So the firmware clips off and filters the uV noise, that seems to be the real "technology" here.
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #455 on: September 19, 2017, 04:02:42 AM »
We need to step back and look at the forest. At the end of the day it's a $20 meter.

Complaining about stuff like this seems like saying "I bought a Ford Fiesta and it can't even tow a 5000lb boat (can you believe it??)"

 

Online IanMacdonald

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #456 on: September 19, 2017, 04:05:44 AM »
You buy a $20 meter then can't sleep at night because it has a +/-20uv dead spot? Schadenfreude.

For that price I'm expecting a Higgs detector.  :-DMM

Seriously it's a damn good meter for the money, though temperature would be handy and I'd pay a bit more to have that. Save carrying two meters. 
 

Offline Fungus

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #457 on: September 19, 2017, 06:27:59 AM »
For that price I'm expecting a Higgs detector.  :-DMM

And powered by dilithium crystals.

Seriously it's a damn good meter for the money, though temperature would be handy and I'd pay a bit more to have that. Save carrying two meters.

It's OK, but nothing special apart from the price.

The missing mA range is a bummer I don't see how people can lose sleep over a dead spot in the uV range but not worry about lack of mA. The square wave output is a waste of a selector switch position IMHO.

I actually prefer using my AN860B+ to my AN8008 even though it's bigger. The AN8008 feels really cheap and plasticky in comparison.

I've got my fingers crossed that the AN8008 is just a clever marketing move to sell a load of meters and the 'AN8009' will be the real multimeter - the meter that everybody wanted in the first place, ie. with temperature, mA and the missing REL/MIN/MAX buttons built in. We know the chipset can do it...  :popcorn:

Size-wise, I'd like it to be a little bit bigger than the AN8008. The selector switch could stick out a bit more at the ends instead of having them rounded off into the dial, too.

Also: The AN8008 screen contrast needs a lot of work and the backlight is pathetic.

 

Online xavier60

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Re: EEVblog #1007 - Is a $25 Multimeter Any Good
« Reply #458 on: September 19, 2017, 09:26:35 AM »
Regardless of the low price of these meters, the dead spot is present due to manufactures' choice.
The 1uv resolution is very useful to me for finding shorts on laptop main boards by tracing ground plane voltage drops,
by comparing quick readings.
A slow zero offset drift is no problem. A large +/-20uv dead spot could be a problem. Offset drift will be adding or subtracting to this dead spot.
The AN8008 in Dave's review doesn't seem to have any dead spot.
I didn't buy the AN8008 just because it was cheap. I mainly use Fluke 87V DMMs.
Hioki AS100D vom, HP 54645A dso, Fluke 87V dmm, AN8008 dmm
 


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