Author Topic: EEVBlog 121GW Discussion thread  (Read 308359 times)

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Offline Terry01

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Re: EEVBlog 121GW Discussion thread
« Reply #1675 on: November 20, 2019, 11:31:38 am »
Seems it's right in the middle of the stack when compared with other decent meters. 1 second either way isn't a big deal really.  :-+
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Offline daveyk

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Re: EEVBlog 121GW Discussion thread
« Reply #1676 on: November 20, 2019, 03:38:01 pm »
Shorting the leads together, then it taking 2.5 seconds to show something <0 ohms and then that reading <0 floating around and slowly raising to maybe .200 or .260 ohms over several more seconds is an issue if you are trying to trouble-shoot circuits that are low in resistance to begin with.  The inability for the meter to settle down with shorted leads, make the REL button not applicable.

The manual mode does not have this issue, but my complaint with the manual mode, is that unless you spend mental energy on the meter verses the circuit you are working on, trying to figure out what range you are on is difficult, at least for me.  I think a good fix would be to better enumerate the display to show what manual range you are on.  There is one manual range (I think the second press of the range button), that floats around too.  Most manual ranges are fast and stable, I just have a hard time figuring out what range I am on.  Is it not a dot matrix display?  Can not the firmware display whatever it needs to?  Kindly rework the ohms display to make it easier to tell what manual range I am on, and I think the problem is fixed.
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1677 on: November 20, 2019, 04:32:08 pm »
Shorting the leads together, then it taking 2.5 seconds to show something <0 ohms and then that reading <0 floating around and slowly raising to maybe .200 or .260 ohms over several more seconds is an issue if you are trying to trouble-shoot circuits that are low in resistance to begin with.  The inability for the meter to settle down with shorted leads, make the REL button not applicable.

The manual mode does not have this issue, but my complaint with the manual mode, is that unless you spend mental energy on the meter verses the circuit you are working on, trying to figure out what range you are on is difficult, at least for me.  I think a good fix would be to better enumerate the display to show what manual range you are on.  There is one manual range (I think the second press of the range button), that floats around too.  Most manual ranges are fast and stable, I just have a hard time figuring out what range I am on.  Is it not a dot matrix display?  Can not the firmware display whatever it needs to?  Kindly rework the ohms display to make it easier to tell what manual range I am on, and I think the problem is fixed.

When Dave ran this test, he suggested the drift was due to finger pressure on the button.  The same you may see when probing a circuit.  So I removed the mechanical switch and repeated the test....


I have included my attempt to reproduce Dave's speed test in Part 4.   Dave does claim the "...I checked, the Keysight "drifts" in a similar way,.... "
https://youtu.be/-eUkSufMK5A?t=460
I overlaid Dave's two meters to better show how the 121 compares with the Keysight meter.    I also included more information about my test.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 
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Offline ElectricPower

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Re: EEVBlog 121GW Discussion thread
« Reply #1678 on: November 22, 2019, 02:40:41 pm »

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.
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Online Brumby

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Re: EEVBlog 121GW Discussion thread
« Reply #1679 on: November 23, 2019, 02:17:44 am »

I am quite new here in the forum, but have read some in the multimeter thread regarding 121GW here and it seems there is a lot of error with it?

I wonder if I should order one, but became skeptical when I read the thread.

This thread provides a rather unusual connection between those who purchase a product and those involved in its development and production.  As such, all the personal preferences and minutae that any given owner may have can be aired directly - with the idea of influencing the development to suit them.  This is not something I have ever seen with ANY other commercial product.

As such, the voices here express a point that they feel is worth addressing - and while this may be a widespread concern, we can only be certain that it is a concern for those who have voiced it here.  One or two squeaky wheels here may not represent the concerns of the thousands who own and use this meter - who tend to just quietly work with the meter as supplied.

I would suggest you read the "issues" carefully and decide if anything mentioned would really affect you.  This is your homework.  You might normally have to go trawling around the net to find this information for any other product - but you have it encapsulated here.


Disclosure: I do not own a 121GW - not because of any the reports, but because I do not have the need.  My current equipment line-up covers more than I require at this time.

... but I AM interested.
 

Offline Doom-the-Squirrel

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Re: EEVBlog 121GW Discussion thread
« Reply #1680 on: November 23, 2019, 02:58:45 am »
Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

 

Offline EEVblog

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Re: EEVBlog 121GW Discussion thread
« Reply #1681 on: November 23, 2019, 06:30:32 am »
Sorry if this has been asked before, but would the 121GW be a good choice for automotive electrical and electronics?

Not really.
A simpler less precise meter would be a better choice, like a BM235 or an Automotive variant of that:
https://brymen.eu/shop/bm319s/
 

Offline firewalker

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Re: EEVBlog 121GW Discussion thread
« Reply #1682 on: November 23, 2019, 10:19:51 am »
I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it.  :D :D :D

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Offline EEVblog

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Re: EEVBlog 121GW Discussion thread
« Reply #1683 on: November 23, 2019, 10:22:22 am »
I teach electronics to automotive technicians. They are in a stage that they can use a DMM to measure sensors etc with ease. I gave them 121GW to use for a change. After 5 minutes the wanted to break it.  :D :D :D

Yes, the more rugged BM235 is more suited to field and automotive use IMO.
And if you need the features of an automotive meters like tacho/dwell then you need a specific automotive model.
Best to start a new thread asking for the best automotive meter.
« Last Edit: November 23, 2019, 11:01:56 am by EEVblog »
 

Offline in06khattab

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Re: EEVBlog 121GW Discussion thread
« Reply #1684 on: November 24, 2019, 02:20:18 am »
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?
 

Offline jancumps

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Re: EEVBlog 121GW Discussion thread
« Reply #1685 on: November 24, 2019, 12:59:00 pm »
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

No. You can switch the beeper on or off, but for continuity, it will always beep. The screen does not flash.
 

Offline dr.diesel

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Re: EEVBlog 121GW Discussion thread
« Reply #1686 on: November 24, 2019, 01:15:57 pm »
Is it possible to silence the beep in continuity mode and use the screen flashing as an indicator?

This would be a great feature!

How about a config file on the SD card as well for custom options:

continuityflash=1
autopoweroff=45
ble=1
defaultDCVrange=2

etc
 
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Offline in06khattab

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Re: EEVBlog 121GW Discussion thread
« Reply #1687 on: November 24, 2019, 04:28:48 pm »
Surely, that is a simple software update?
This can be enabled in the setup menu.
Then if the buzzer sounds, flash the screen.

If the firmware was available, this is very easy to add (without the setup menu).
 

Offline EEVblog

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Re: EEVBlog 121GW Discussion thread
« Reply #1688 on: November 26, 2019, 02:09:01 am »
17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/
 

Online Brumby

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Re: EEVBlog 121GW Discussion thread
« Reply #1689 on: November 26, 2019, 03:43:42 am »
Geez....  Now you're really tempting me - but I have to take care of the Christmas budget first.


(Not to mention the reaction I will get if I bring another multimeter into the house  ;D )
« Last Edit: November 26, 2019, 03:45:24 am by Brumby »
 

Offline BrianG61UK

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Re: EEVBlog 121GW Discussion thread
« Reply #1690 on: December 02, 2019, 03:49:37 am »
17 units of the old kickstarter build stock left, 20% discount off the already sale price on the EEVblog website, coupon code fluxcapacitor
https://www.eevblog.com/product/121gw/
What improvements are we missing out on if we choose to save by getting one of these old build 121GWs?
 

Offline BVH

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Re: EEVBlog 121GW Discussion thread
« Reply #1691 on: December 08, 2019, 12:37:33 am »
Is there a new 20% off for Christmas coupon code available?
 

Offline popol

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Re: EEVBlog 121GW Discussion thread
« Reply #1692 on: December 11, 2019, 01:18:42 pm »
Hi,

I'm busy looking at the 121GW schematic, and I have some questions.

On the set "Burden", what is the component FB2 BEAD ??
See link :



It's a capacitor? or another type of room? If anyone knows what it is,

Witch value have this component ?

thanks for the answer.

« Last Edit: December 11, 2019, 01:20:45 pm by popol »
 

Offline Grandchuck

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Re: EEVBlog 121GW Discussion thread
« Reply #1693 on: December 11, 2019, 02:23:40 pm »
A ferrite bead?
 

Offline gdewitte

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Re: EEVBlog 121GW Discussion thread
« Reply #1694 on: December 11, 2019, 02:52:38 pm »
 

Offline popol

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Re: EEVBlog 121GW Discussion thread
« Reply #1695 on: December 11, 2019, 03:56:56 pm »
Ok, thank-you for your response. But witch are caracteristics of this component ( uH, pF, Ohms ? )

 

Offline CDaniel

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Re: EEVBlog 121GW Discussion thread
« Reply #1696 on: December 11, 2019, 05:09:05 pm »
I don't think inductance is very important like in a normal LC filter , after all is just a very short wire , but the ferrite is made "lossy" ( hysteresis losses ) so high frequency is "consumed" inside .
 

Online ejeffrey

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Re: EEVBlog 121GW Discussion thread
« Reply #1697 on: December 11, 2019, 09:22:13 pm »
The document gdewitte linked to shows some typical impedance vs. frequency curves, but a typical ferrite bead has very low impedance at low frequency -- basically just a short wire, and then cuts on with a very low Q inductance (i.e., mostly resistive) at higher frequency, typically several MHz to several hundred MHz.  Far above anything a multimeter cares about.  Their purpose is to limit EMI pickup from external sources (like FM radio) and also to prevent emissions of internally generated high frequencies such as from digital electronics and switching power supplies.  If chosen at all appropriately they have negligible effect on the actual desired signal.
 

Offline popol

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Re: EEVBlog 121GW Discussion thread
« Reply #1698 on: December 13, 2019, 04:54:03 pm »
Ok, its clear now, thank-you for your response. 8)
 

Offline npelov

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Re: EEVBlog 121GW Discussion thread
« Reply #1699 on: January 18, 2020, 06:30:43 am »
Yesterday I gave up on logging onto the SD card and tried the android app - it worked fine for a while - I could save the data in csv. But then after about one hour the save button did not work any more. If I press save nothing happens.
The last time I was able to save something was at the 50 minute mark. I pressed the save button and because nothing happened in a second or two I pressed it again. Then the usual share dialog appeared, but when I saved the file another share dialog appeared - I guess it was just taking it's time.

And it's a separate thing I can't save the csv file on the phone itself - I can only put it in an email, google drive and other things that usually popup in "share file".

Is there any way to log data with this DMM in a stable way?

You would think that a DMM advertised as "logging" would be able to log and after an year and a half the major bugs would be fixed. I'm sorry Dave but you are nip-picking other products for much smaller flows. I know you are not directly responsible for the firmware, but you should be more pressing. Your name is on the meter.

BTW the 500mA range is unstable. Sometimes I get quite a bit of noise. I'll be back later with numbers, because I forgot how much it was jumping around. I think I was in fixed 500mA range measuring 10mA. I think it's not like that all the time, but I'm not sure. I'll try to investigate more. The low burden is pushing the limits a bit but I think there is more to it, because sometimes it's relatively stable.
 
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