We do those all the time at the calibration company where I work they come under a different brand but the instrument is the same and they are spot on 99% of the time, never had one failing the cal, quite surprising for a multi brand meter thumbs up for the manufacturer.
I learn so much here just wanted to see how to measure many meters. now i can fix more things and design stuff armed with this multi multi-meter test. The good you do for us all these days.
Those are tight results across that sample size. This is a good indication that Brymen QC works well. (With a lot of the cheap stuff it is doubtful whether there is any QC at all.)
Uni-T fanboy reporting for duty. My 70D is bang on spec after 18 years of daily use. Maybe the newer ones are not up to scratch, but the older models have been reliable workhorses for me
+arcadeuk I had the chance to check 3 UNI-T meters so far and found them all to be barely in spec, all on the low side. Two of them were from 2006, the other one from around 2010. Glad to hear that your's is still bang on after all these years. I am afraid something in that companie's factory calibration procedure has changed to the worse since then. The meters from 2006 were both taken off duty, they had selector switch problems.
statistical sampling is the only way to test for batch quality so this is a good start stop repeating yourself it's hard to take your pitch over coffee at breakfast
+Chip Guy Vids - Don't know how I could miss that... and I just looked back 5 months of videos but didn't find it. Can you provide me a link or episode number, please?
+ElmerFuddGun Hmm you are actually right, the only things I could find are the teardown photos he usually takes: www.eevblog.com/product/bm235-multimeter/ So there has been a teardown, but I can't find the video either. Maybe I got that mixed up and there are only the photos. I definetly watch too many teardown vids from various bloggers ;)
+Chip Guy Vids - LOL... and the only thing I found on it was on the eevblog2 channel of the unboxing. He didn't take it apart in that video just unboxed it. So I guess my "disappointed" stands! Thanks for the reply and checking though.
Scarcely known fun fact: if you do 51 measurements (or in this case if you measured 51 different meters) you would actually get two significant figures on your standard deviation (or in this case %RSD)
What would have been interesting in the AC range would be distorted waveforms. In my experience the cheaper meters easily go at the edge of their spec or outside of it. Just don't complain if they do it on square waves
It seems to me that for some ranges the errors of the meters aren't centered around the correct value. For instance, the 10k resistance and 5Vdc are mostly below true value, while Vac measurements are above the correct value. Anyone know where this bias comes from? I wouldn't think Brymen's callibration standards are off?
It's true that UT absolute precision isn't so great. They have the count and the features but they don't seem to bother with calibration which is a shame. They could easily be better than Fluke. The 5-10$ classic 3½ digit meters are actually surprisingly accurate.
Electronics amateur question here: is such a crazy level of precision ever needed for a multimeter? Like 4 digits for the 6V range? I mean, for most of electronics, 1 digit is more than enough, let's say you need 5V, if you can get anywhere between 4.9 and 5.1 it's usually no problem at all. I'm thinking maybe reference voltages or other stuff like that?
Typically you don't need the full number of digits when you're just just checking something. In most cases three significant digits is going to be adequate. However, consider the effect of range changes: with this particular 6000 count meter when you change range from the 6 V range to the 60 V you drop down to three digits -- e.g. "6.000 V" to " 6.01 V". (There is usually some 'headroom' where you can actually read up to e.g. "6.030 V" or such before the range change is required, but the effect is still present when you go past that threshold.) For work where you want to measure -- or set -- values more accurately, you need to step up to more significant digits. This is where 50 000 or 100 000 count meters come in, or your more capable bench-top meters.
16:10 Ever thought of cleaning the inside of the banana plug? It used to make a difference for me (and I started with a mirrored analog unit that needed to be calibrated everytime you use the resistance function so I would notice these things). Interesting vids, if a bit long at times.
" A Warranty VOID if NOT Removed policy applies to the screws on this product" I love the specs and looks of this. The manual even shows photographs of the insides during a 'tear down'! When will you be selling an EEVblog oscilloscope? Do you ship to the USA?
Years ago, Harbor Freight Tools, the local "cheap Chinese tools" store here in the USA was having a sale on pocket DMM's. Something insane like $2 US each. Perfect for using in places where I didn't want to risk the nice Fluke I had at the time or when I needed additional meters. Drop one into a pond? Back over it with the truck? Who cares! So I bought five of them and took them to work where I had access to calibrated (NIST-traceable) voltage standards. I was *shocked* at how accurate they were...
They will blow up in your hand if you a accidentally have the test leads plugged into the current socket and you measure higher voltages. It's more like a toy multimeter with no protection. Use it at your own risk!
At 8:25, Geeze I hate that expression, gets me every time. I spent 2 minutes googling out of sheer spite to find the price was about 11 echidnas per ohm! So now everybody knows!
Hey! What's happened to your old Fluke 17b?? Try replacing the battery in the first instance... My old Fluke 17b, my first ever "good" DMM, is still going strong years after buying it. My Fluke 87 gets more use, but the 17b still gets used and is still great! I look forward to seeing further investigation into the 17b conundrum!
Maybe the firmware knows when they are tested, just like the diesel engines of Volkswagen? Just make them tend to get still unsuspecting close but closer than the actual accuracy is to typical testing values...
From the manual Dave's Note: Proper ceramic HRC (High Rupture Capacity) fuses are expensive, but they are designed to fail safe and not explode. That makes you safer. Don't be a tight arse and put cheap glass ones in there instead! If you wanted cheap you should have bought a cheap arse meter instead of this one. Beware the fakes on ebay! haha
Is there anything special about these meters? Did they receive special treatment, or a discounted price? I've got a BM869s, but I've always like the look of this handy little thing too...
40 multimeters? seems kind of excessive for 1.5 guys... Interesting results although kind of tedious when everything works so fine and no explosions, no magic pixie dust, no smoke released not even a tiny bit of sparks.
I want one of the EEVBlogs multimeters! I suppose it won't be shipped to the states though? I'd like to do a video testing with my Extec then with an EEVBlog tester. :) I'd be using my pinball machines 5V and 12V metal stand ups on the board,
Now I am getting even more excited to get the BM235 that's coming may way. This video will hopefully open the eyes of the UNI-T fanboys. I had one of these at work and they showed exactly the same behaviour. All the values were barely within specs and one the low side. Now we got a new one (Voltcraft VC9xx) and may have gotten just another UNI-T, rebadged version, doh. I should have taken care of that myself....
Hi Dave, i love your Blog and your videos and i just bought and received a EEVBlog Bryman 235 multimeter from Amazon, great meter! A fellow TH-camr, Joe Smith just posted a video review of the 235 about a month ago and mentioned that the continuity element is not loud on his at all, however mine is real loud. Has there been a change in the design? Also I thought the range switch may make the vol go up or down?
I want you to do a comparison of LP record to digital, showing the glaring weakness of vinyl and also on the other end expose "Hi-Res" audio of Sony, et. al., for the fraud that it is.
Does this meter beep in diode mode, very hard to find except for fluke and agilent, I do believe a true electronics meter should have the basic feature of diode beep
Can you recommend any cheap autoranging multimeters. The reason why i ask is that I only have one of those 30$ crap multimeters and I am only in the age of 15 and I do not have 200 $ for a multimeter
it's Daves Custom Version? i hope it have metal liner for battery cover screw and it not using battery snap. battery snap it's not recommanded i think.
I'm confused on the +2d statement. When it says "plus two digits", does that mean the least significant digit can fluctuate by a count two? in other words, with a 5.000V input, 4.998 to 5.002 is the range (not counting the percentage accuracy specified). I'm simply not understanding the +2d statement.
Well-written specs usually have something along the lines of "+/- (0.3% of reading + 2 digits)". So a zero signal should yield in-spec indications between -2 digits and +2 digits, for that example. The Brymen manual explains how to interpret their figures in the paragraph before the tables of specifications.
+boggisthecat So when you say "two digits" you mean "plus or minus a value of 2" in the least significant digit, right? So in this case it would be 4.998 to 5.002?
Typically there will be calibration adjustment points in the lowest mV range, then one or two on higher ranges. It's a linear fit type requirement (the "y = mx + c" stuff). AC is then usually adjusted at 1 kHz or something similar, and sometimes at 65 Hz to get a near (US) mains frequency point -- but not at mains frequency in order to minimise issues with signal coupling etc. It is sometimes a bit surprising how minimal the adjustment processes are, even on the old trimpot type meters. A lot of work goes into minimising adjustment requirements as that not only makes manufacture easier, but should improve long term stability. (This is for good quality meters: cheap stuff is often festooned with trimpots.)
I'm not sure if it's included on the BM235, but I have a BM257s and it has an opto socket on the back which enables the connection of an additional cable for interfacing with a computer via USB. Not sure if it would make this specific experiment any quicker or easier though.
1:39 I laughed at the pile about to fall as he finishes to say "no human can stack multimeters like this",
+Victor Arnaiz Yep, you can just start to see the top start to move just before the cut.
+Victor Arnaiz I didnt , thought it was stupid to be honest
Of course, you forget, +Paul Spiller. I was present at an undersea, unexplained mass sponge migration!
+Paul Spiller not a Ghostbusters fan?
"A man with one watch always knows what time it is. A man with two watches never knows the time."
@Janardan S - Hmm. I can't find that quote in the Book of Proverbs.
A broken clock is right twice a day. A working clock is wrong all day long.
this is one of the best video because this is actually metrology and science at work.
We do those all the time at the calibration company where I work they come under a different brand but the instrument is the same and they are spot on 99% of the time, never had one failing the cal, quite surprising for a multi brand meter thumbs up for the manufacturer.
I learn so much here just wanted to see how to measure many meters. now i can fix more things and design stuff armed with this multi multi-meter test. The good you do for us all these days.
Those meters fell over didn't they :)
+Wessel Lemmer Haha yeah, you could see them start to fall just as he cut away
+Wessel Lemmer You'll have to subscribe to my 2nd channel to find out...
+Wessel Lemmer They were falling when he cut. Maybe a human did stack 'em.
That's because the video isn't out yet. He said to subscribe, because that's how you can be notified of future videos on the channel.
+Wessel Lemmer Don't worry, they are built like brick dummies.
You should make some sort of torture test for multimeters
+super awsome minecrafter it was done, he tried to jolt them
*pile starts casually falling*
Dave Jones already did torture test himself before you write comment i think. we knew already who's Dave Jones.
+super awsome minecrafter Yes, the big question is: will it blend?
+FDK i hope something blows up, or the meter just spins.
Would be interesting with a typical (critical) tear down video of the EEVBlog multi meter :)
I was verry impressed with my test results. Especially the mV and current uA/mA ranges.
You could have just written out the result range and placed a tick by each one that had that result, would have been a touch quicker.
+Allison Pell Doh, yeah. Would have given me an instant binned graph too.
+EEVblog Nothing worse than being told, or figuring out a better way after you have finished. Happens a lot to me, anyway.
+excavatoree I just didn't give it any thought at all.
+EEVblog well, the one good thing about writing out each individual result is that it allows you to see which out of the batch were the most accurate
Incredible little meter! Just couldn't get any better than this for a 6000 count meter.
Those are tight results across that sample size. This is a good indication that Brymen QC works well.
(With a lot of the cheap stuff it is doubtful whether there is any QC at all.)
I once scored a defective non reading Fluke 177 on a local Ebay variant.
Turns out it was on Hold!
Best buy ever.
Uni-T fanboy reporting for duty. My 70D is bang on spec after 18 years of daily use. Maybe the newer ones are not up to scratch, but the older models have been reliable workhorses for me
+arcadeuk I had the chance to check 3 UNI-T meters so far and found them all to be barely in spec, all on the low side. Two of them were from 2006, the other one from around 2010. Glad to hear that your's is still bang on after all these years. I am afraid something in that companie's factory calibration procedure has changed to the worse since then. The meters from 2006 were both taken off duty, they had selector switch problems.
My unit is in the mail. This video helped a lot in alleviating my buyers remorse...
That stack fell down, didn't it?
statistical sampling is the only way to test for batch quality so this is a good start
stop repeating yourself it's hard to take your pitch over coffee at breakfast
In future news, next week customers of Dave's multimeters complain of dead batteries ...
+Wholly Mindless yeah yeah, but they been touched by Dave!!! We have his DNA!!!
+Paxmax So, we can clone him and get his clone to pedal an exercise bike generator to recharge the battery?
Do we dare hook up thoose energetic persons to some generator...? you know black holes and stuff might pop into existance...
It would be nice to see the normal distribution graphs, just like the one you did with the resistor values a while ago.
The Uni-T multimeters seem to drift about a lot on the resistance ranges (and AC voltage, if I recall correctly). Always a PITA to calibrate.
Bought on of these but on back order :(
Was pleasantly surprised to find the price is $AUD and not $USD
+simontay1984 It's £81($AUD155) through PayPal or at least when I bought it earlier today
so a shipped EEVblog multi-meter is with guaranteed Dave DNA
probably not enough for a clone though
From looking at these reviews I found that this meter hit the dreaded 999 reading quite often while a Fluke hit the mark spot on.
Take it apart first! I thought that was the rule? ;-)
Disappointed.
+ElmerFuddGun LOL he already did that ;) ...of course. A few episodes back...
+Chip Guy Vids - Don't know how I could miss that... and I just looked back 5 months of videos but didn't find it. Can you provide me a link or episode number, please?
+ElmerFuddGun Hmm you are actually right, the only things I could find are the teardown photos he usually takes: www.eevblog.com/product/bm235-multimeter/ So there has been a teardown, but I can't find the video either. Maybe I got that mixed up and there are only the photos. I definetly watch too many teardown vids from various bloggers ;)
+Chip Guy Vids - LOL... and the only thing I found on it was on the eevblog2 channel of the unboxing. He didn't take it apart in that video just unboxed it.
So I guess my "disappointed" stands! Thanks for the reply and checking though.
+ElmerFuddGun Well... let's wait for it, one or the other way there will be a teardown... I hope...
good luck dave!
Scarcely known fun fact: if you do 51 measurements (or in this case if you measured 51 different meters) you would actually get two significant figures on your standard deviation (or in this case %RSD)
What would have been interesting in the AC range would be distorted waveforms. In my experience the cheaper meters easily go at the edge of their spec or outside of it. Just don't complain if they do it on square waves
Cant believe I watched the whole thing! Thanks Dave.
Does this mean that you'll be selling them as "used"..? :-P
Additional QA checks performed, you mean? ;)
It seems to me that for some ranges the errors of the meters aren't centered around the correct value. For instance, the 10k resistance and 5Vdc are mostly below true value, while Vac measurements are above the correct value. Anyone know where this bias comes from? I wouldn't think Brymen's callibration standards are off?
That was pretty cool Dave. Thanks
It's true that UT absolute precision isn't so great. They have the count and the features but they don't seem to bother with calibration which is a shame. They could easily be better than Fluke.
The 5-10$ classic 3½ digit meters are actually surprisingly accurate.
Have you considered a ramped test, checking how well the reading tracks from 0 to Max or Max- to Max+.
okok we are sold-good campaign for your products-they do sound spot on though.
Electronics amateur question here: is such a crazy level of precision ever needed for a multimeter? Like 4 digits for the 6V range? I mean, for most of electronics, 1 digit is more than enough, let's say you need 5V, if you can get anywhere between 4.9 and 5.1 it's usually no problem at all.
I'm thinking maybe reference voltages or other stuff like that?
Typically you don't need the full number of digits when you're just just checking something. In most cases three significant digits is going to be adequate.
However, consider the effect of range changes: with this particular 6000 count meter when you change range from the 6 V range to the 60 V you drop down to three digits -- e.g. "6.000 V" to " 6.01 V". (There is usually some 'headroom' where you can actually read up to e.g. "6.030 V" or such before the range change is required, but the effect is still present when you go past that threshold.)
For work where you want to measure -- or set -- values more accurately, you need to step up to more significant digits. This is where 50 000 or 100 000 count meters come in, or your more capable bench-top meters.
That Pilot G-2 pen @2:15. My fav pen for my work which requires black pen only so i go through boxes of these a year.
What a cute Casio calculator! Very pretty!
But i prefer Sharp from the same era, mid 80ies.
These seem to be pretty good meters. Nice one Dave!
That Ghost Busters reference made my evening, thanks Dave. :-)
So, is this your "piece de resistance?"
Sorry. I couldn't help it.
16:10 Ever thought of cleaning the inside of the banana plug? It used to make a difference for me (and I started with a mirrored analog unit that needed to be calibrated everytime you use the resistance function so I would notice these things). Interesting vids, if a bit long at times.
Pilot G-2... the only non-fountain pen I use. The Duck's Guts!
you could have done a small build off competition for the "Pick of the litter" multimeter that was the most accurate of them all.
where do I get my hands on a EV Multimeter?
+Outlookhazy Are those prices US $ or Australian $ ?
+GadgetUK164 Australian $, makes them a bit cheaper
+Outlookhazy Don't see that one on the Amazon store though. Only one blue one and it's a B&K.
+White Tiger Gaming it's not on the Amazon store it is in a drop down menu at the top.
www.eevblog.com/product/bm235-multimeter/
TheDessonator Ah! Ok, now I understand the "Is it AU$ or US$ question. So is it AU$ or US$? :D
" A Warranty VOID if NOT Removed policy applies to the screws on this product" I love the specs and looks of this. The manual even shows photographs of the insides during a 'tear down'! When will you be selling an EEVblog oscilloscope? Do you ship to the USA?
He missed to write one result (10:02) and that later he added it. I don't mean anything bad, just quick little notice :)
1:41 cut before the fall haha
i would like to see the bandpass of those multimeters.
For me, as an audio person... the band pass is a huge deal...
I would have added a test with the voltage reversed to see how well the auto zero works.
+1 very impressed. The UNI-T drifts, so it needs tweaking. My Fluke 867B is still within 1 count :D
Years ago, Harbor Freight Tools, the local "cheap Chinese tools" store here in the USA was having a sale on pocket DMM's. Something insane like $2 US each. Perfect for using in places where I didn't want to risk the nice Fluke I had at the time or when I needed additional meters. Drop one into a pond? Back over it with the truck? Who cares! So I bought five of them and took them to work where I had access to calibrated (NIST-traceable) voltage standards. I was *shocked* at how accurate they were...
They will blow up in your hand if you a accidentally have the test leads plugged into the current socket and you measure higher voltages. It's more like a toy multimeter with no protection. Use it at your own risk!
+Chingus696 Thankfully, I know what I'm doing and won't make that mistake.
Worth a thumbs up for that job.
Lol, i'm propbly gonna do a practicum at Advantest this year. Didn't even know the made these end consumer devices.
Wonder if the meters made it into the peltier-o-matic environmental chamber?
i use unite meters from maplin .same sort of gear .good and cheap.i ended up buying 5 diff models
But the real question is: would you rather be present for multimeter mass turbulance, or an undersea unexplained mass sponge migration?
Wohoo, it would be a pleasure to have a EEVblog multimeter :)
Graphing the distribution of results may be interesting
Change the voltage/current polarity, when measure DC
At 8:25, Geeze I hate that expression, gets me every time. I spent 2 minutes googling out of sheer spite to find the price was about 11 echidnas per ohm! So now everybody knows!
I am in the market for a Klein Tools MM6000 with AUTOHOLD how will this meter stack up against the Klein and why should I buy it?
Hey! What's happened to your old Fluke 17b?? Try replacing the battery in the first instance... My old Fluke 17b, my first ever "good" DMM, is still going strong years after buying it. My Fluke 87 gets more use, but the 17b still gets used and is still great! I look forward to seeing further investigation into the 17b conundrum!
+Samgab EDIT: Doh! Just saw EEVBlog #853, and where you discovered the "fault"... :)
Maybe the firmware knows when they are tested, just like the diesel engines of Volkswagen? Just make them tend to get still unsuspecting close but closer than the actual accuracy is to typical testing values...
An interesting show, but I'm not sure. This can be selected party specifically for this test.
oh Dave, what have you gotten yourself into this time?
For sale - 40 second hand multimeters.
From the manual
Dave's Note: Proper ceramic HRC (High Rupture Capacity) fuses are expensive,
but they are designed to fail safe and not explode. That makes you safer.
Don't be a tight arse and put cheap glass ones in there instead! If you wanted
cheap you should have bought a cheap arse meter instead of this one.
Beware the fakes on ebay!
haha
Is there anything special about these meters? Did they receive special treatment, or a discounted price? I've got a BM869s, but I've always like the look of this handy little thing too...
40 multimeters? seems kind of excessive for 1.5 guys... Interesting results although kind of tedious when everything works so fine and no explosions, no magic pixie dust, no smoke released not even a tiny bit of sparks.
Now you can't sell them as "sealed" anymore :( BUT you can now sell them as "touched by Dave".
I want one of the EEVBlogs multimeters!
I suppose it won't be shipped to the states though?
I'd like to do a video testing with my Extec then with an EEVBlog tester. :)
I'd be using my pinball machines 5V and 12V metal stand ups on the board,
Now I am getting even more excited to get the BM235 that's coming may way.
This video will hopefully open the eyes of the UNI-T fanboys. I had one of these at work and they showed exactly the same behaviour. All the values were barely within specs and one the low side. Now we got a new one (Voltcraft VC9xx) and may have gotten just another UNI-T, rebadged version, doh. I should have taken care of that myself....
+Chip Guy Vids all voltcraft things are rebadged.
+FoxMccloud42 I know, but I expected Metex (which I got and is rather good)
this is how quality control should be done
I have one of those! Thanks Dave :)
Hi Dave, i love your Blog and your videos and i just bought and received a EEVBlog Bryman 235 multimeter from Amazon, great meter! A fellow TH-camr, Joe Smith just posted a video review of the 235 about a month ago and mentioned that the continuity element is not loud on his at all, however mine is real loud. Has there been a change in the design? Also I thought the range switch may make the vol go up or down?
Hello. Which brand and multimeter is best for everything ( home, electrical work and electrician user)
DMM with combined a AC \ DC Volts switch position, endorsed by the EEVBlog?
+gmaildotcom It software saves and defaults to your last setting. No worries.
Great! Well thought. Definitely something you don't see on cheap generic meters.
***** If you don't use AC, it won't default to it.
What're the major differences between BM235 and BM257?
no usb
My UNIT UT61E is pretty much spot on unlike yours. Only thing that is not good on mine is the current measurement..
I want you to do a comparison of LP record to digital, showing the glaring weakness of vinyl and also on the other end expose "Hi-Res" audio of Sony, et. al., for the fraud that it is.
Hmmm, no teardown add-on?What's inside units?
You are reading a comment.
+PINKBOY1006 Winning?
Does this meter beep in diode mode, very hard to find except for fluke and agilent, I do believe a true electronics meter should have the basic feature of diode beep
I just found out about these meters and they are all gone already :(
I think dave didn't realize how fast they would sell.
They are also sold under different brands as well. The Greenlee is a Baymen.
Can you recommend any cheap autoranging multimeters. The reason why i ask is that I only have one of those 30$ crap multimeters and I am only in the age of 15 and I do not have 200 $ for a multimeter
Wow, I wished I could afford buy one of these!
But in my country each one of these costs more than the minimal wage per month ) :
Where can I get updates for the 2nd batch of EEVblog branded brymens?
How this multimeter compares to other models near the same price range? I would like to buy something more serious :)
Did those meters come with batteries installed or did you install a battery in each and every one of em?
It's like I'm really back in EE lab
it's Daves Custom Version? i hope it have metal liner for battery cover screw and it not using battery snap. battery snap it's not recommanded i think.
yeah. it have metal liner and nice aaa holster!!!!!!! i will buy it!!!!
EEVblog version ? i can trust them.
12:07 I could finally start breathing again. Thanks.
I'm confused on the +2d statement. When it says "plus two digits", does that mean the least significant digit can fluctuate by a count two? in other words, with a 5.000V input, 4.998 to 5.002 is the range (not counting the percentage accuracy specified). I'm simply not understanding the +2d statement.
+Hilltop it's 2 digits up over 5.000 and 2 digitts under 5.000 used too be + - 2 digits. but some manuals dont put the + and - simbols on the manual.
Well-written specs usually have something along the lines of "+/- (0.3% of reading + 2 digits)". So a zero signal should yield in-spec indications between -2 digits and +2 digits, for that example. The Brymen manual explains how to interpret their figures in the paragraph before the tables of specifications.
+boggisthecat So when you say "two digits" you mean "plus or minus a value of 2" in the least significant digit, right? So in this case it would be 4.998 to 5.002?
+Hilltop Correct. When the spec says "+2 digits", it means two counts (+/- 0.002 for a 3.5-digit meter).
+Peter Ridge Got it! I was confused whether it was two *counts* or *two places* - i.e. tenths, hundredths, thousandths, etc
You should have had your son help with the data collection. He seems like he could have moved the plugs from meter to meter.
Why calibrate on the 50mV vs 5V? It seems to me it would result in higher accuracy calibrating at 5V.
+GreenAppelPie The input to the ADC is (usually) XXXmV full scale. You get the best accuracy when you aren't using the input divider.
Typically there will be calibration adjustment points in the lowest mV range, then one or two on higher ranges. It's a linear fit type requirement (the "y = mx + c" stuff).
AC is then usually adjusted at 1 kHz or something similar, and sometimes at 65 Hz to get a near (US) mains frequency point -- but not at mains frequency in order to minimise issues with signal coupling etc.
It is sometimes a bit surprising how minimal the adjustment processes are, even on the old trimpot type meters. A lot of work goes into minimising adjustment requirements as that not only makes manufacture easier, but should improve long term stability. (This is for good quality meters: cheap stuff is often festooned with trimpots.)
+EEVblog Thanks! I understand that reasoning, but also find it arguable.
Did you design those or is it just a sponsorship/branding deal? You should have put a USB port on it for reading the measurement.
I'm not sure if it's included on the BM235, but I have a BM257s and it has an opto socket on the back which enables the connection of an additional cable for interfacing with a computer via USB. Not sure if it would make this specific experiment any quicker or easier though.
I love the shirt I'll check my nearest baby GAP for one next time I'm out. =)
A giveaway would be pretty awesome
should have made 'em dark gray with a yellow jacket - Sparkfun would've snapped up the lot! :P
i blew up my multimeter, where can i buy this EEVBlog branded one?
+afroninjadeluxe At www.eevblog.com/product/bm235-multimeter/