Author Topic: New EEVblog BM786 Multimeter  (Read 69507 times)

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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #25 on: October 14, 2020, 12:46:04 pm »
Really nice. I have some questions:
Does it work well with rechargeable AAA batteries?
Does it come with a Cal certificate?

It should work ok with rehcargables:
https://www.eevblog.com/forum/testgear/us$150-class-multimeter/msg3077681/#msg3077681
No cal certificate, just like other Brymens.
 

Offline BravoV

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Re: New EEVblog BM786 Multimeter
« Reply #26 on: October 14, 2020, 12:52:11 pm »
Does it work well with rechargeable AAA batteries?

+1 , and also Lithium cells ? As these have tad higher voltage.

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #27 on: October 14, 2020, 12:54:11 pm »
BTW, I don't actually have the blue version yet, it's on the courier truck. I only have the red proto version.
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #28 on: October 14, 2020, 12:54:33 pm »
Does it work well with rechargeable AAA batteries?
+1 , and also Lithium cells ? As these have tad higher voltage.

Yes, confirmed ok by Brymen.
 
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Offline tszaboo

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Re: New EEVblog BM786 Multimeter
« Reply #29 on: October 14, 2020, 01:02:45 pm »
Really nice. I have some questions:
Does it work well with rechargeable AAA batteries?
Does it come with a Cal certificate?

It should work ok with rehcargables:
https://www.eevblog.com/forum/testgear/us$150-class-multimeter/msg3077681/#msg3077681
No cal certificate, just like other Brymens.
Well, 3.55V/3= 1.18V. That is around 50% DoD of a NiMH, so not perfect.
I guess we buy a pack of alkaline then.
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Online 2N3055

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Re: New EEVblog BM786 Multimeter
« Reply #30 on: October 14, 2020, 03:27:33 pm »

A question?

Will firmware be field upgradeable?
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #31 on: October 15, 2020, 02:25:27 am »
Will firmware be field upgradeable?

Technically there is a programming header inside, but Brymen are super secret about their processor used. So that's a "no" for now.
At least it's programable, unlike the BM235 which uses an OTP part.
 
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Online Monkeh

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Re: New EEVblog BM786 Multimeter
« Reply #32 on: October 15, 2020, 03:43:50 am »
Will firmware be field upgradeable?

Technically there is a programming header inside, but Brymen are super secret about their processor used. So that's a "no" for now.
At least it's programable, unlike the BM235 which uses an OTP part.

I'd say send one off for a decapping and see what it is, but I wouldn't want to hurt a relationship for idle curiosity.
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #33 on: October 15, 2020, 10:49:32 am »
Will firmware be field upgradeable?

Technically there is a programming header inside, but Brymen are super secret about their processor used. So that's a "no" for now.
At least it's programable, unlike the BM235 which uses an OTP part.

I'd say send one off for a decapping and see what it is, but I wouldn't want to hurt a relationship for idle curiosity.

My guess is one of the really low end asian brands. On both the BM235 and this one they talk about struggles having enough memory to add new functions, so it's very memory limited.
 
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Offline Electro Fan

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Re: New EEVblog BM786 Multimeter
« Reply #34 on: October 15, 2020, 07:48:14 pm »
BM786 looks really good but any chance it actually weighs 635g?  Fluke 179 is similar in dimensions (although can't say for sure about the depth/thickness front to back as far as case/probe holder vs. meter itself), but the 179 is 420g.  Also, compare the weight and HWD in the 786 manual to the weight and HWD of the BM869S.  Maybe the 786 manual specs for weight (or otherwise maybe HWD) need an edit?  Just curious.
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #35 on: October 15, 2020, 10:41:16 pm »
BM786 looks really good but any chance it actually weighs 635g?  Fluke 179 is similar in dimensions (although can't say for sure about the depth/thickness front to back as far as case/probe holder vs. meter itself), but the 179 is 420g.  Also, compare the weight and HWD in the 786 manual to the weight and HWD of the BM869S.  Maybe the 786 manual specs for weight (or otherwise maybe HWD) need an edit?  Just curious.

Yeah, mistake. It's 414g with batteries. My 77-IV is 408g.
 
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #36 on: October 15, 2020, 10:45:09 pm »
vs the 77IV for those curious.
 
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Offline sdt

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Re: New EEVblog BM786 Multimeter
« Reply #37 on: October 15, 2020, 11:05:03 pm »
How do the DC+AC modes work?

Does it flip back and forth between separate DC & AC measurements?
 

Offline Electro Fan

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Re: New EEVblog BM786 Multimeter
« Reply #38 on: October 15, 2020, 11:30:49 pm »
vs the 77IV for those curious.

Your new meter is going to be very popular.  Congrats!
 

Online rsjsouza

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Re: New EEVblog BM786 Multimeter
« Reply #39 on: October 16, 2020, 05:35:40 pm »
How do the DC+AC modes work?

Does it flip back and forth between separate DC & AC measurements?
I don't know about this meter, but in my BM857 (also single display) the AC+DC adds the DC with the AC RMS value of the input, and you can cycle between AC, DC and AC+DC modes using the buttons.
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Offline HKJ

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Re: New EEVblog BM786 Multimeter
« Reply #40 on: October 16, 2020, 06:24:38 pm »
AC+DC is always a single value compromised of sqrt(sqr(AC)+sqr(DC)), the question is how the meter does this.
Most meters reads a AC value, then a DC value and then do the calculation, i.e. reducing the update rate, a few meters may be able to do a combine AC+DC measurement in one conversion. When doing separate AC and DC measurement there is also a issue about the time needed to do the switch between them.
 
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Offline MosherIV

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Re: New EEVblog BM786 Multimeter
« Reply #41 on: October 16, 2020, 07:02:33 pm »
I think te question about ac+dc is more about how is it displayed with only single display.

My Fluke 187 does it but has dual display.
 
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Online rsjsouza

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Re: New EEVblog BM786 Multimeter
« Reply #42 on: October 16, 2020, 07:55:22 pm »
I think te question about ac+dc is more about how is it displayed with only single display.

My Fluke 187 does it but has dual display.
That is how I understood the question when I provided my reply above.
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Offline ogdento

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Re: New EEVblog BM786 Multimeter
« Reply #43 on: October 16, 2020, 10:29:26 pm »
This is nearly the only meter I'd ever need.  My only gripe is there's no low-z (on the 786)... will there be an eevblog-blue 789?
 

Offline sdt

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Re: New EEVblog BM786 Multimeter
« Reply #44 on: October 16, 2020, 11:45:36 pm »
That is how I understood the question when I provided my reply above.

Thanks for the replies, that clears up a lot.

Neither of my two meters (ut139c & an8008) have any sort of combined AC & DC modes. I've seen meters with dual display, but not come across DC+AC before.

To be honest I'd never even considered what the AC mode would report in the presence of a DC offset. From the comments I take it the AC mode is AC coupled and ignores the DC offset, and the DC+AC mode is the numeric sum of what the DC and AC modes would report.
 

Offline ve7xen

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Re: New EEVblog BM786 Multimeter
« Reply #45 on: October 17, 2020, 12:14:10 am »
To be honest I'd never even considered what the AC mode would report in the presence of a DC offset. From the comments I take it the AC mode is AC coupled and ignores the DC offset, and the DC+AC mode is the numeric sum of what the DC and AC modes would report.

Yes, though it is the geometric mean, not sum. It is giving you the total RMS value of the input, rather than the RMS value of the AC or DC components only (which is what you [ideally] get in those respective modes).

I think there are some DMMs out there that don't actually AC-couple the AC range, so YMMV, but this is what would normally be expected.
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #46 on: October 17, 2020, 06:14:13 am »
will there be an eevblog-blue 789?

No, I'm not allowed to sell it, as there is an official Australian dealer who has already said they want to carry it.
Good luck trying to buy it from them: https://www.cabac.com.au/
I don't know why they bother with Cabac, I'd sell 100 times the meters they would.

 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #47 on: October 17, 2020, 06:17:44 am »
AC+DC is always a single value compromised of sqrt(sqr(AC)+sqr(DC)), the question is how the meter does this.
Most meters reads a AC value, then a DC value and then do the calculation, i.e. reducing the update rate, a few meters may be able to do a combine AC+DC measurement in one conversion. When doing separate AC and DC measurement there is also a issue about the time needed to do the switch between them.

This is why the AC+DC mode is on the DC range switch. It can measure DC and then switch in an AC coupling cap, and then it display the  combined DC+AC value.
« Last Edit: October 17, 2020, 06:19:46 am by EEVblog »
 

Offline wolfy007

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Re: New EEVblog BM786 Multimeter
« Reply #48 on: October 17, 2020, 07:38:50 am »
will there be an eevblog-blue 789?

No, I'm not allowed to sell it, as there is an official Australian dealer who has already said they want to carry it.
Good luck trying to buy it from them: https://www.cabac.com.au/
I don't know why they bother with Cabac, I'd sell 100 times the meters they would.

I remember them, their online store is still shit I see, I remember I ended up buying a Brymen meter I wanted from Europe instead of them.
 

Offline Wytnucls

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Re: New EEVblog BM786 Multimeter
« Reply #49 on: October 17, 2020, 11:02:46 am »
On my multimeter (UT71D), the voltage AC+DC is constantly converted to true RMS by the AD636.

Vrms= Avg x [Vin^2/Vrms]

If AC only is required, Vin is routed through a capacitor before reaching the true RMS converter.
The AC/AC+DC switch works on the V AC selector position only.
The DC component is read on the V DC selector position.
« Last Edit: October 17, 2020, 01:05:10 pm by Wytnucls »
 
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