Author Topic: Brymen BM789  (Read 38342 times)

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Online tautech

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Re: Brymen BM789
« Reply #225 on: August 08, 2024, 07:10:37 am »
............
I have interacted with many 2nd class electricians and none of them had a meter with low-z or even know what to do with it.
FTFY.  :P
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Offline J-R

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Re: Brymen BM789
« Reply #226 on: August 08, 2024, 10:17:17 am »
You can pick apart any general statement by providing specific use cases.  If you don't agree with the generalization, then that's fine.  It doesn't invalidate the generalization...

The workbench has your best equipment within reach, maybe more than you need.  When you're away you have to make do with what's nearby.  Put another way, I've got the multitool in my pocket, toolbox in the truck but tool tower in the garage/shop.

Low Z has a few uses, but I say typically on the bench it's rare because you have drawers of resistors or a substitution box for creating any specific load you want.  Away from the bench a common use is to see if that voltage you're seeing is "real" or just induced via nearby wiring.

Sometimes your bench DMM is too far away or you want the display right next to your face when you're deep in a repair.  So the BM869s seems pretty well feature packed for that.  BUT, no reason a BM789 can't be fine too.

And what do you say about my DMM that has a thermal camera built-in?  Hit the button, now I can instantly see that loose connection or an overloaded circuit, etc.  So Brymen is the loser now...
 

Offline joeqsmith

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Re: Brymen BM789
« Reply #227 on: August 08, 2024, 11:19:43 am »
People here are starting to agree that the scope is better for AC so what is left for dual display meters ?

I already stated I use it for the BM869s thermocouple inputs.

My scopes are limited to 8-bits.  For most cases, it's not a problem for what I use it for.   Here I set mine up to measure AC power by over sampling and fitting the data to remove some of the linearity errors:   


Offline Fungus

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Re: Brymen BM789
« Reply #228 on: August 08, 2024, 11:51:09 am »
People here are starting to agree that the scope is better for AC so what is left for dual display meters ?

Nothing.

That's why the BM857s is the best multimeter for bench use - simple, no display clutter, one function per dial position (almost).  :)

(and the Fluke 113 for "electricians" ... and you can own both for less than the price of a Fluke 87V)
« Last Edit: August 08, 2024, 11:54:34 am by Fungus »
 

Offline AVGresponding

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Re: Brymen BM789
« Reply #229 on: August 08, 2024, 12:33:12 pm »
Considering low-z a feature for electricians is just wrong.
You wouldn't want an electrician to work on your electronics.
I have interacted with many electricians and none of them had a meter with low-z or even know what to do with it.
Electricians like stick meters with a few leds because a number on a screen is to much and I agree with them, measuring voltage thousands of times a day becomes irrelevant if it's 220 or 230.

Clearly you don't know any competent electricians. And you also misunderstand what an electrician might need a DMM for.

Two-probe/Steinel testers are already low-Z, and the reason for this is simple; they eliminate ghost voltages caused by capacitive and inductive coupling, and therefore give a "true" reading of the presence of dangerous voltages. In the UK, if you want to be certified for testing fixed wiring installations to BS2391 (which you need for signing off any electrical alteration work that is a part of such an installation), you must use a two-probe tester; a DMM is not acceptable.
You'd use an installation tester in the test and verification process, which again, is already low-Z. The two-probe testers are purely for fault finding and verifying a circuit is dead, prior to locking it off, so it can be worked on.

Electricians only use DMMs for things like troubleshooting industrial machinery and controls, where you need a bit more flexibilty. Basic domestic/commercial/industrial fixed wiring does not require it.

NCV voltsticks are useful when you're trying to find an individual circuit in a trunking with dozens or hundreds of cables; good luck getting a DMM in there. That function on a DMM is useful only for home users/hobbyists imo.
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Offline EEVblog

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Re: Brymen BM789
« Reply #230 on: August 11, 2024, 10:28:13 pm »
That's why the BM857s is the best multimeter for bench use - simple, no display clutter, one function per dial position (almost).  :)

Shots fired!  8)
I'll take the BM786 thanks.

 

Offline J-R

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Re: Brymen BM789
« Reply #231 on: August 12, 2024, 02:55:29 am »
That "simple" argument is objectively bogus and doesn't hold up to scrutiny.  The BM857s has a significant number of shared functions and multiple settings per switch position just like the other models:

BM857s has 9 function switch positions.  4 are shared functions in the strict sense.  7 have multiple settings.
BM859s has 9 function switch positions.  5 are shared functions in the strict sense.  9 have multiple settings.
BM867s has 9 function switch positions.  5 are shared functions in the strict sense.  7 have multiple settings.
BM869s has 10 function switch positions.  7 are shared functions in the strict sense.  10 have multiple settings.
BM786 has 8 function switch positions.  4 are shared functions in the strict sense.  7 have multiple settings.
BM789 has 9 function switch positions.  5 are shared functions in the strict sense.  8 have multiple settings.

Also, the BM857s/BM859s and BM78x have 8 buttons, while the BM867s/BM869s have 6.

Ultimately, due to the mode memory that can't be disabled, all Brymen DMMs can be a pain to use in many cases because you never know what function you'll get when you flick it on, unless your life is so dull that you memorize the last setting or write it down every time you turn it off.

The 121GW with the mode memory hack is a joy by comparison.  The setting I'm using is remember the mode while it's on, but reset to the white-lettered functions after power-off.  Predictable.  Dare I say "simple".
 

Offline Fungus

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Re: Brymen BM789
« Reply #232 on: August 12, 2024, 05:22:09 am »
Ultimately, due to the mode memory that can't be disabled, all Brymen DMMs can be a pain to use in many cases because you never know what function you'll get when you flick it on, unless your life is so dull that you memorize the last setting or write it down every time you turn it off.

The only thing I really toggle on BM857s is Ohms/continuity, and it's really easy to know when it's in the wrong mode.

No need to even look at the screen, just touch the probes together.

That's why the BM857s is the best multimeter for bench use - simple, no display clutter, one function per dial position (almost).  :)
Shots fired!  8)
I'll take the BM786 thanks.

That's a good second choice but it has three functions on a single range (Ohms/continuity/Siemens)...   :P

(size is also similar)

I feel this is a topic that's never been explored. Which meter needs the least button pushes and mode selections in daily use?
 

Offline Fungus

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Re: Brymen BM789
« Reply #233 on: August 12, 2024, 05:26:34 am »
Another topic:

What's more useful?

a) A BM869s,
or
b) A BM857s and a $30 Zeeweii oscilloscope?


Edit: I should point out that the Zeeweii has an "auto" mode that scales both horizontal and vertical to match the incoming signal. It's fast at doing it, too. Just probe the DUT and there's the wave on screen complete with measurements, no need to do anything else.
« Last Edit: August 12, 2024, 06:00:23 am by Fungus »
 

Offline multiJ

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Re: Brymen BM789
« Reply #234 on: August 12, 2024, 08:00:16 pm »
I feel this is a topic that's never been explored. Which meter needs the least button pushes and mode selections in daily use?

Fluke 117 and certain meters from Hioki (4252, 4256, 4261, 4282) come to mind, if we are not too far off topic.
 

Offline EEVblog

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Re: Brymen BM789
« Reply #235 on: August 12, 2024, 11:05:30 pm »
I feel this is a topic that's never been explored. Which meter needs the least button pushes and mode selections in daily use?

Fluke 117 and certain meters from Hioki (4252, 4256, 4261, 4282) come to mind, if we are not too far off topic.

Winner:
 

Offline Fungus

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Re: Brymen BM789
« Reply #236 on: August 13, 2024, 12:23:38 am »
I feel this is a topic that's never been explored. Which meter needs the least button pushes and mode selections in daily use?
Fluke 117 and certain meters from Hioki (4252, 4256, 4261, 4282) come to mind, if we are not too far off topic.

I guess I should have added "and have good accuracy specs and are not missing any major functions that an EE needs, like mA/uA".
 

Offline porter

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Re: Brymen BM789
« Reply #237 on: September 29, 2024, 11:54:40 pm »
I should also add that the Flir DM64 and DM65 are OEM equivalents of the Brymen DM235 (it seems that the DM64 and DM65 are themselves identical except that the DM65 is packaged with slip-on alligator clips!).  Flir's US website is still selling the DM64 for $50 (only shipping to the USA as far as I know).  Since the last time I looked at Flir's website the number of multimeters has been reduced significantly.  Don't know if that's a temporary thing or the company shifting focus?

I wanted to mention that I ordered the DM64 last year at the sale price while it was still  listed on the Flir website. It didn't arrive after a few weeks, but I got a call from them telling me that they are shipping the DM66 for the same price.  I'm very happy with the quality.
I'm posting this ( a little bit late) because I appreciated the phone call from Flir and shipment of a newer model.
« Last Edit: September 29, 2024, 11:57:30 pm by porter »
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Offline rce_pirate

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Re: Brymen BM789
« Reply #238 on: December 03, 2024, 04:18:20 am »
new post here. the flir dm66 is the brymen 235 repackaged. better plasics though.
 

Online Sorama

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Re: Brymen BM789
« Reply #239 on: December 03, 2024, 07:21:02 am »
I use a Brymen 785 on the bench.
This model is not mentioned often on the forum.

Maybe it’s not a model sold across the ocean?

But I do like it a lot.
« Last Edit: December 03, 2024, 07:22:58 am by Sorama »
 

Offline chebo

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Re: Brymen BM789
« Reply #240 on: December 03, 2024, 07:58:39 am »
Hi owners!
Who could repeat my simple experiment to check the accuracy of the Crest mode?
2452095-0
I manually closed and opened the switch shown in the diagram, simulating a voltage drop. The average value for several measurements in the Crest mode was 7.60 V. As a result, the relative error was approximately 4%.
2452099-1 2452103-2 2452107-3
Is this a normal error? What will happen to you?
« Last Edit: December 03, 2024, 08:00:23 am by chebo »
Experience is what we got instead of what we wanted...
 

Offline joeqsmith

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Re: Brymen BM789
« Reply #241 on: December 03, 2024, 01:30:38 pm »
Hi owners!
Who could repeat my simple experiment to check the accuracy of the Crest mode?
(Attachment Link)
I manually closed and opened the switch shown in the diagram, simulating a voltage drop. The average value for several measurements in the Crest mode was 7.60 V. As a result, the relative error was approximately 4%.
(Attachment Link) (Attachment Link) (Attachment Link)
Is this a normal error? What will happen to you?

I saw your double post about the car battery.  Personally, I would use a scope for that application. 

For the BM789,  assuming we meet the 35ms minimum,  in this range I would expect it to fall within +/-1V.  Yours appears much tighter than that.   

CREST mode (Instantaneous Peak Hold)
Accuracy: Specified accuracy +/- 100 digits for changes > 0.35ms in duration
Availability: Voltage and Current functions
Resolution: 6000 counts

For the BM869s:
Crest mode (Instantaneous Peak Hold)
Resolution: 5000 counts
Accuracy: Specified accuracy +/- 100 digits
for changes > 0.8ms in duration

For the Fluke 189:
Specified accuracy ±100 counts up to 5,000 count (full
range) reading. For higher peak readings (to 20,000
counts), specified accuracy ± 2% of reading.
250 μs for repetitive peaks; 2.5 ms for single events. Use DC function settings below 20 Hz. 50 mV range not specified.


Offline chebo

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Re: Brymen BM789
« Reply #242 on: December 03, 2024, 01:48:42 pm »
For the BM789,  assuming we meet the 35ms minimum,  in this range I would expect it to fall within +/-1V.
Yes, it seems so. And that's what Brymen's engineer answered me too: "07.60V" reading falls in "+- 100 digits" tolerance.
It was not very clear to me what these +-100 digits meant. But now everything has become clear. If you add this systematic error to the readings, the result coincides with what the oscilloscope showed.
Experience is what we got instead of what we wanted...
 

Online coromonadalix

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Re: Brymen BM789
« Reply #243 on: December 03, 2024, 02:44:22 pm »
brymen 785  would be like some fluke 83 85 87 series ... no dual displays, but  vs the dual display ones, the price gap is not huge ... ?

old Gossens  have the auto mode i sometimes use,  switch between ohms volts  ...  practical  loll
 

Offline joeqsmith

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Re: Brymen BM789
« Reply #244 on: December 03, 2024, 06:27:35 pm »
For the BM789,  assuming we meet the 35ms minimum,  in this range I would expect it to fall within +/-1V.
Yes, it seems so. And that's what Brymen's engineer answered me too: "07.60V" reading falls in "+- 100 digits" tolerance.
It was not very clear to me what these +-100 digits meant. But now everything has become clear. If you add this systematic error to the readings, the result coincides with what the oscilloscope showed.

I had a quick look at the manuals for some of the other higher end meters I have on-hand but don't believe any of them are spec'ed much better. 

Offline AVGresponding

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Re: Brymen BM789
« Reply #245 on: December 04, 2024, 06:18:19 am »
Polycarbonate is much more brittle than polyethylene, which is also highly resistant to acids and solvents.
LOL!

Calling polycarbonate brittle is like calling copper highly resistive.

Things made with PE:
sandwich bags
freezer bags
vapor barrier
food containers
Fluke meters


Things made with PC:
Bullet proof face shields
motocross goggle lenses
motorcycle helmets
explosion proof cabinets
Brymen meters

Here's your bulletproof plastic:  https://www.eevblog.com/forum/testgear/brymen-bm786-case-cracking/
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