Testing random meters for accuracy with DIY resistance tester.
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- เผยแพร่เมื่อ 4 ก.ค. 2019
- I made a simple resistance tester for meters that tests them with 1, 10, 100, 1K, 10K, 100K and 1Mohm 1% resistors. I chose 0.5W resistors for the lower ranges and a high voltage resistor for the 1Mohm range to allow for checking insulation testers.
If you want to make a similar tester for electrical installation meters the two most useful resistor values are 1 ohm and 1 megohm. The 1M resistor will need to be rated for 1kV or more for insulation testers that can test at that voltage. It's a good way to check a meter is functioning correctly.
The only time I've seen electrical installation test meters go out of calibration is when they've been abused. Usually involving applying the probes to a live supply and then attempting to do a resistance test on it despite the warning light being lit. Modern meters try to be idiot proof by preventing the test being done, but ironically they are less reliable because of the more complicated circuitry.
The routine calibration thing appeared at the same time as the Part P protection racket was pushed for by organisations who make a LOT of money from it. It's part of the same detached paperwork industry that brought us the five-day electricians certificate. (The same reason meters now need to be idiot proof.)
It's reassuring to see that my old American-made Fluke from around the early 1990's is still reading accurately.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
www.bigclive.com/coffee.htm
This also keeps the channel independent of TH-cam's advertising algorithms allowing it to be a bit more dangerous and naughty. - วิทยาศาสตร์และเทคโนโลยี
Can we get a teardown of the robin dmm; so that we may see what went wrong ?
That might be good, but there might be nothing to see. It might be internal within the chip!
That'll be fun. Taking them apart is fairly easy, but fiddly to get back together. What's my money on? Intermittent rotary switch or overloaded part somewhere in the 200mA low impedance loop. I guess that's the first thing I'd check: is it chucking out at least 4V O/C and 200mA S/C. I assume the cal lab would have checked the fuse, which is usually user-replaceable for *reasons.*
Then he needs an electron microscope
Probably going have to get one from Alibaba instead of ebay
It's them crap Kodak battery's from poundland powering the robin FFS
@@BoB4jjjjs but that's not the BigClive way of doing things is it? "it MIGHT not be visible" 😁
If it in any way can be taken apart, it means it should be taken apart!
Friend: "What did you do today?"
Me: "I watched a guy plug things in for 20 minutes"
"porn?"
@@sephirothsoul999 Yes, he was screwing his nuts!
Hmm... This gives me something to do with the 0.01% 5K resistors that were in the junk bin at work. (also, those things were $7 apiece, and they're 0603!)
"Metal Foil" (laser trimmed) is my guess. Rock solid too
Suggestion: Instead of using absolutely accurate 100k resistor (which you may not have on hand) in that gadget you can use two parallel 200k or four 100k (two parallel sets of two resistors in series) and match them so they give you bang on value instead of sticker, that 100k is actually 99,69 kΩ.
Like that: 1 / (1 / 203,0 + 1/ 197,1) = 100,0032 or
1 / (1 / (99,84 + 100,78) + 1 / (99,73 + 99,66)) = 100,0015
I love my trusty Fluke meter. Got it free from College as the were getting new ones so the department chair gave the older ones to us Electrical students.
Did they know they gave them away 😉
I love it when schools give old stuff to students. From my highschool I ended up with Modern Biology by moon mann otto from the 1950's. Also a few programming books, Computer Confidence, 2 for basic, 1 for basic plus, 2 for pascal, and 1 for fortran. Now these languages are worthless to modern day highschoolers with smart phones, but I like retro and programming so they're pretty cool.
Had friends at school dancing terms with the school signed a waiver or to.
Put this way used to have an Electronics lab.
Excetera excetera.
Good times.
High School in the 90s.
Big Clive, you are so right when you say you just know when your meter 'is giving rogue readings'. You kinda develop a gut intuition on things after you been around meters long enough.
when the switch is inbetween settings
You never fully trust the meter to show you the whole picture, always taking it with a little bit of skepticism.
The goal of having a Fluke is to make that trust a little bit stronger, whereas the 5 dollar multimeter will have near zero trust.
Who else was waiting with anticipation for the cheapy yellow meter?
me me me in the tune of adafruit ;)
To be honest, I kinda want to see it go "bang"... And I'm sure that Clive can make it happen in a controlled manner.
Since I have one myself it was nice to see that it was decent. And for most practical purposes a decent meter is what you want since most circuits do work within 10% tolerance range and this was better than that.
The downside with that cheapy yellow meter is that you have to open it to replace the battery, which is a vanilla 9V battery. I did put in a lithium one in mine to ensure long life.
But I did discover that when the battery starts to run flat the meter starts to give weird measurements, but that's common for most electronics - bad power supply can cause all kinds of strange problems.
Thank you Big Clive, for the little mention about the UT210E's Clamp based DC ammeter. Just been trying to find a meter to help me find a slow drain on a car, and having looked at many reviews of similarly priced and more expensive meters I think I'll be buying that one.
I'm currently watching this video, and I don't know if I have the capacity to resist finishing it. You really lead the way, and you're always opening gates for young minds who might have reluctance towards being induced to appreciate these kinds of fields. I love how you charge in without any filter and we're lucky to have you on a platform that presents no interference in your content. I'm always alternately oscillating between you and AvE, and it's nice to have this content directly available.
Totally agree regarding Uni-T meter, very useful, very accurate and nifty.
Having researched the cost of good decade boxes, i have resigned myself that a design such as yours is currently the only way forward for non-professionals like myself and i like your design very much. Well Done !!
Considering that 50 years ago your normal serviceman's analog meter was typically 3% for a good meter and 5% or worse for a cheap meter, having just about anything being within 1% over the whole range is really pretty darn impressive.
Of course its also worth noting that the world itself is pretty much a 10% thing, and 1% is overkill for most measurements. It gives modern people a false sense of worry when something is off by 2%.
50 years ago resistors were 20% tolerance, too.
And they still managed to land on the Moon.
@@markrainford1219 Allegedly (runs away and ducks for cover) 😉
@@tinplategeek1058 rofl
The bigger problem is that many people confuse accuracy and resolution. Just because a meter shows 4 digits, doesn't mean that it's accurate to 0.1%, yet that's how many folk understand it. In practice, great accuracy is rarely needed. What's more important is relative accuracy - when measuring two voltages, it often suffices to know which one is highest. For example, is the input signal above or below the supply voltage?
I have a very similar Fluke to yours, i have the 77. Which was given to me at the end of my MoD apprenticeship 28yrs ago. It still works absolutely perfect. As you say, the Daddy of meters.
Great video Clive love the tester you made
The 830b yellow and similar one is basically an ICL7106 chip from millions of years ago.
There is a 100mv ref set pot inside for the voltage and current.
Resistance uses a ratio metric method,.
The first time you showed that meter with the DC current clamp I looked one up and bought it. Amazing thing to have.
Christian Banks
Yes, it’s twitchy for low DC current but otherwise works well. I checked mine against our calibration equipment and it was well within specification - not always the case for cheap Chinese meters.
I've had one for about 2 years now and I use it at work every day, brilliant meter, I might get another to keep in the car
I've had one for about 2 years now and I use it at work every day, brilliant meter, I might get another to keep in the car
Nice functional test for testing meters. It brought back memories. I was in the field of Metrology at a magor helicopter company before my broadcast career. Most analog meters are tested at full scale and digital too with standards. We used to test the electricians meters functionally like what you did and sticker it accordingly but, anything that touch the aircraft they had to be calibrated correctly. We would take reading at multiple points of the ranges with before data and if we did adjust, we had to have after data for traceability under NIST then under ISO 9000 and shorten the cycle time of the meter being used then find out if that meter was used on anything that was critical. It was a pain but interesting work. If you want an accuracy test use a Kelvin 4 wire bench ohmmeter. It uses the voltage drop method to display resistance on your lower resistances ranges with gold clips. I remember measuring conduction levels of connections of pins and measuring down to 10 to minus 9th place one time for repeatable tests because of a claim that the pins would ware after so many uses and the resistance would change. Just to prove Cramolin (ProGold) on connectors work better. It was weeks of testing and taking data.
I also have a Fluke 23.That has been my go to meter. A real workhorse and extremely rugged guy.
my Uni-T was delivered just before I found this video, you have given me some confidence in what is a very reasonably priced bit of kit !
If you bought the Uni-T UT210E then you have one of the best meters around.
bigclivedotcom what do you do to make these horrid little leaflets readable, my eyes are not as young as they were. Is there a downloadable/printable copy available ? Otherwise I’m going to have to learn to use the Gdam printer again !!
This is a really helpful video, especially for anyone starting out who wants to know if a cheap meter will be adequate until they can afford a better one. The answer nowadays seems to be "Yes."
Yes it is. I recommend starting with a cheap meter and then moving up to a better one when you decide what features are most useful to you.
Took our meters to a wholesaler where they had a calibration day, the basics are a free calibrationn 'test' and a sticker to say it's within spec.
But they also offered 'calibration' to put it right if needed
the calibration company was Robin, and they'd even accept other makes.
Can't fault Robin, my fluke/robin 1653 MFT tester has been going strong for 10 years
@@scriptguru4669 That's a very early model, I suspect more than 10 years!
I bought one of those Uni-T clamp meters because I saw you using it. I love that little guy.
Interesting vid, as I remember making a similar resistance box when I was at collage, way back in 1984! A slightly more complex unit, it was called a decade box, all the various resistors were hard wired inside & a rotary switch was used to change the resistance to the output terminals, which were connected to the device under test.
I then worked for a year in the equipment calibration & repair lab of a well known defence & space company (Marconi systems), all the test gear could be traced back to the National physics laboratory. Very interesting work, some of it was covered by the Official secrets act!
Well done, my dad had a fluke the entire time I was growing up, I dont know the model number but it had this fantastic grey soft but able to provide protection case. Super thick. He also has 77 III model I'm supposed to put it back together for him. The first one crapped out a few year ago battery acid if I remember right. Cheers from the hot muggy kansas.I'm still working on that transmission. Just fyi.
We here in Australia have a similar yearly cal check for some industries and government contractors.
I use a NATA calibrated meter and standards to do the tests.
I have found that most, almost 99% of DMM are still good 5 to 10 years after purchase, even the lower (not elcheepo) China products. unless they have been damaged due to high volt or current.
The insulation tester, that failure is not uncommon among most of the brands, possibly caused by connection to a live circuit.
Even though they can be expensive, they are usually a throw out item.
These days with the low cost of high precision resistors its not hard to make a simple resistance checker unit.
Good video mate..
Great to have a resistor and capacitor reference test bed .Essential
Does your yellow "cheapy meter" maybe have a half-dead battery, by any chance? (They use 9V/PP3 batteries IIRC - I have that same model, which was my first ever meter around 15 years ago!)
I'm totally speculating, but it wouldn't surprise me if it struggled to measure higher resistances when its power source wasn't quite at the voltage it was expecting...
(I've recently bought a few 0.01% resistors with very low thermal coefficients, which are fun! They're around £5-15 each, and you can't get higher values with that level of tolerance from regular suppliers (they're special orders from Vishay and the like), but they're a relatively cheap way of getting an idea of the accuracy of your meter(s) when you don't have a high-accuracy meter to act as your reference. Likewise I'm getting some tight-tolerance voltage references for the same reason. I'm on a bit of a metrology obsession atm! 😹)
The yellow hobby £5 cheapy DT830 and their related clones do shit themselves eventually. If mine is anything to go by, after a number of years of good service, one by one the ranges have a nervous breakdown, the screen shows extra decimal points, then it's goodnight vienna. The leads are generally cack from day one, and need throwing away.
you and me both! Metrology can really take a hold of you, I am building Dave Jones's (EEVblog) micro current box at the mo so I can add a Nanoamp scale to my fluke 79 meter, he wrote a fascinating article all about the theory of operation, that's a great read! I also have been buying 0.01% resistors for the build. For me it all started from wanting to no exactly how much current my Arduino draws when "asleep" now its getting out of control! I wish I had the kit that he has, also, Marco Reps is another guy who loves his Metrology. I just no I'm gonna want to test the calibration of the calibrated calibrator ! Wonder if there's professional help for me ? Voltage references are another step along the path that is precision. Stuff like measuring the current generated when you shine a light on an LED or how many lemons and bits of zinc to power a Atmega328p-AU all await me!...good luck with your experiments!
Actually you can order less than 0.001% R tolerance ceramic arc-in-noble-gas-coated alloy resistors. But they are vacuum-tubed and aren't tolerate high currents. And - not from ordinary bulk suppliers, obviously. Prices at all times were comparable to ordinar mid-range family car for the 4 of these.
There are instrument calibration services available, but they charge a fair amount of money. Which is reasonable, considering the equipment they have, the environment they have to keep it in, and that they have to pay people that actually know what they are doing to use it.
@@thephilpott2194 Try turning the dial a bunch of times to clean the contacts. I have a not so cheap Mastech that had an intermittent dial switch, ended up cleaning it with Deoxit to make it usable again.
So many toys and all of them work fine.
Very nice.
I have a lovely old AVOmoving coil meter that lives on the shelf over my bench.i have checked it against a calibrated decade resistance box and it's dead on. Back in the day it would of been very expensive. Now can get same level of accuracy from a ten quid digital meter!
I bought one of those TackLife meters a couple of months back, amazing value, measures everything incl temperature...all for little more than i paid for my el-cheapo meter some 15+ years ago
I bet it doesn't measure inductance and/or ESR.
hahaha HAHAHA HEHEHEHEHE south east London.. It's Saturday morning..it's my birthday..it's really sunny..London Pride today...and I've just watch Our Man on the Isle of Man check the calibration on his multimeter collection...FANTASTIC WHAT A START TO THE DAY...THANKYOU BIG CLIVE💎💎💎💎💎👍👜
Harbor Freight here in the US gives those cheap meters away for free on occasion, I've got one in every car and my GoldWing too... Hard to beat free, and if it bites the bullet, get another ;-) They actually seem to work surprisingly well too... Great test!!! Amazing how accurate even the cheap meters are! I've got a rather expensive DC Clamp Amp meter as well for diagnosing auto issues, VERY handy indeed!!!
thanks for the ut210e recommendation that thing is incredible
and so cheap that its a must have
I'm would have though you would have purchased the 211b for the higher resolution. If anyone could justify it, that would be you. Your gear choices are so practical. You are like anti Dave when it comes to equipment. Love your work, keep them coming,
Just the video I wanted to see. Thanks BC.
At one time I had a 1,000,000 Megohm resistor. It was in a radiation detector as part of the resistance bridge to measure the resistance of air. When air ionizes, the disassociated electrons migrate towards a positively charged plate in the chamber. This was an alternative to the Geiger Muller avalanche tube to detect ionizing radiation. It was stolen from storage.
I saw my first Fluke digital meter demonstrated at the local electronics distributor many years ago, including putting the "soft" cover on it and dropping it five feet to a concrete floor. You know the guy selling the meter has great faith in the maker's claims when he does that ;-)
Even the cheap ($8US to free) meters from Harbor Freight are reasonably accurate once calibrated, using the most accurate of the AD584 chips (AD584K, with its rated +/- 10mv on its 10.000 volt output - even better with a traceable calibration). If the cheap meter's calibration pot is gently eased to show 10.00 volts *steadily*, then it's within +/-5 mv of the AD584's 10.000 volts. That's more than adequate for checking 12 volt batteries in the small solar systems I dabble in. Biggest so far had 540AH of AGM batteries and 1600 watts of solar and smallest is a shed lighting system with 15AH of battery and a single 30 watt solar panel. If the cheap meter reads 10.00 volts from the AD584, then the desired float voltage of 13.65 volts is very close when the cheap meter shows 13.65 volts - and I'm not out much if the meter takes a 20 foot tumble plus calibration of another of those meters takes maybe 5 minutes ;-)
Your AMECaL ST-9905 didn't make the cut? I got myself one of those after seeing your videos because I liked the big screen.
I just received a meter from AliEx sold as an A830L. It's blue and grey and looks a bit updated from the old yellow cheapy you used here. I got it for the enclosure. Inside it's pretty much identical to the cheapest yellow meter. It's just another ultra basic build of an ICL7106 based meter. The one I got was $4.61 shipped. It's also got a slightly larger display with a backlight.
Acetone strips the silkscreen completely too. It's a nice enclosure for under $5 :-)
-Jake
Cool I was just about to ask you about V and I references I look forward to it. Thanks bud. 😊
Another great video. It shows that expensive meters are not really needed for basic resistance readings. How many places or digits does one really need for resistance readings. At least over 1 Ohm, but I’m curious as to lower readings. I know they are not milliOhm meters, but how low can they go?
I have that same UNI-T meter...I keep it in my backpack when I travel....awesome meter for the $$.
@bigclivedotcom @14:40 what are the batteries like in that meter, if they are a bit low it could explain why it suddenly didn't do as well on the MOhm test.
I was honestly thinking the same
Probably "mature" but no battery low indicator, which would be a fail.
@@bigclivedotcom it is well used :)
The Mastech meter you tested is available from our local Chinese tool importer here in the US and is actually a quite good little meter for all around use.about 5.99 US dollars
The accuracy of cheap digital meters is great. I checked the calibration on many meters where I work and the cheapies aren't tough but they are more than adequately accurate for most jobs. I was just checking a Simpson 260-7 scale and with an tolerance of "2 degrees of arc" you wouldn't have been able to beat the digitals that were half the price for accuracy. (For those who've never heard of a Simpson 260, they were the Fluke 87's of the analogue VOM's)I think your government program is what we call a calibration check rather than a calibration. The meter either meets its spec or fails, no adjustment.
I was replacing lighting at a company that offered meter calibration. After getting all our meters recalibrated for free ( when to the pub with the technician at lunchtime! ) I brought in my very old, brown bakalite, hand cranked, insulation tester for a laugh. I'd had it from my apprentice days when it was third or forth hand when I got it and had had it in the van to show the apprentice along with those immortal lines of "just hold these clips for me and this won't hurt ". So he put through the calibration test on both continuity and insulation and the damn thing passed! Still have it along with its certificate, was fun on sites when the work was inspected and they wanted to see the meters and their calibration certificates. Inspectors just don't have a sense of humour anymore.
Most of the new era of inspectors are just a made up job to keep people employed.
Oh yes ! Many, many tales of that. In one the contractors were installing new emergency lighting in a battery room in steel 20mm conduit. Every bend was formed by 20mm flexible conduit. Client couldn't understand my fuss, although they did agree to run a seperate cpc through the conduit after I said I was quite happy to take the padlock isolation keys home with me if they didn't. Turns out that on a crew of 20 sparks on site, 5 were qualified. The rest were either 6 week wonder boys or actual apprentices. Guess who ended up checking all their work afterwards, even though their own inspectors said it complied ?
As a sweaty youth, if I held the clips tight I felt almost nothing, while the person turning the Megger handle struggled.
Today my neighbor told me he had an $800 snap on meter.
I laughed and said, I have a Fluke 73...
Eight hundred dollary doos? I hope it doubles as a scan tool.
Most likely really big digits!, probably some graphing ability. But, yes, Fluke does the job.
@@nogravitas7585 doubles as a wallet scanning tool.
Zenodilodon
Not true RMS, but a solid meter. We still get a few come into our calibration lab, and they never fail to meet spec despite being very old instruments.
I wonder who Snap-on’s OEM is for multimeters.
@@boggisthecat I love how fast they are, I find a lot of other meters to be really slow and based on averaging during reading. I have seen meter averaging so bad it will shoot up double or more before finding a stable reading. I have next to no complaints when using a fluke. I like the fact they are work horses.
A man can never have enough meters 👍
Carl Richards Nah, anything above 2 (3 as a reach) gets impractical in a world built for those with less.
@@johnfrancisdoe1563
Don't be silly now.
@@johnfrancisdoe1563
You can use a LED as a cheap alternative
ROBRENZ has a series of videos on making a much more extreme version of that resistor box. The point being more along the lines of "Make any conceivable resistance, accurately and precisely". But, conceptually, still a box of resistors.
Saved up for a month and got myself a Fluke 87 and an electronics starter kit off Amazon. Snapelectronics is the set I got. Pretty neat so for!
It looks like it was mainly designed for kids younger than me; but it works
P.S
I also have that red clamp/meter by UniT! My uncle John gave it to me.
Well he let me use it at his office and than said take it home and practice with it. Than he gave it to me.
Anyways thanks for these videos Mr Clive. I’m a gymnastics teen. It’s literally my world. Not by choice.
Your voice is soothing and your content is teaching me to boot. So I get a win win by watching this.
I can shrug off my day and relax.
I know I’m a weird girl. But engineering and pixie wrangling run in the family.
Weird is always a good result. Most technically inclined people come across as weird.
Matt Quinn I did not know he had any! AvE recommends him as well so that’s two people. I’m going to look in to it. Thanks!
Good video! Is there any way to increase accuracy of the testing device resistance values other than use better (accuracy-)rated resistors? Just putting some in parallel will not work since they might be from the same production series (e.g. all -4% off).
Standard bullet crimp connectors can be used in a pinch for custom leads on those cheap meters.
I used to have one of those cheap things, looks suspiciously equal to the D03047 (the one you call CPC, mine was branded as a Grant). They sell for about 7 pounds nowadays, even cheaper than (other) Chinese junk, but surprisingly accurate. It's an OEM design sold under lots of brands and unbranded versions. Note how similar it is to the yellow M-830B. Used mine for about 15 years until it finally broke just two weeks ago, suddenly giving the same rogue readings as the Robin that failed the calibration test. Best value for money I ever had. :-) Despite the excellent experience I still decided to get something a bit more expensive now just for the comfort of having auto range.
If you want to use decent leads with the cheap meters, all you have to do is trim off the shrouds with a utility knife and then use wire cutters to cut off the little plastic button at the end of the conductor that makes the connection. I use a lot of the cheap meters since my students don't really understand concepts like "things break if you use them wrong," but the leads that come with them don't last nearly as long as the meters do even with normal use. I can buy ten or twelve eight or nine dollar meters a year even out of pocket if I have to, but I usually only need to replace two or three a year. The leads they come with, though, are terrible, and don't always work right out of the box.
What is the NPN PNP part of the one meter for? (It's marked before the blue circle on the small cheaper one with a holster. I know NPN and PNP are transistors, but I know nothing about testing them
It measures their gain. The amount they amplify a signal.
Good to see that the cheap and cheerful meters are almost as accurate as the posh ones. The unusual ranges (6v etc) on the Taclife reminded me of the Russian meters (mechanical) that used to be sold cheap. They tended to have unusual ranges like 3v, 30v etc, that frequently meant having to multiply the scale reading by four. They weren't nice. :-(
A number of Fluke meters had ranges such as 6, 60, 600.
Certainly Fluke models 11x. We had many 115s at work, and I owned a 117, which now costs twice what I paid for mine.
As much as we'd like to watch you play with your nuts for hours, MultiContact specially makes a set of drivers that will have you finish in no time at all. They are made in Switzerland and thus unaffordable, but easy to copy yourself. Just take a suitable piece of pipe that fits over the thread and file a step back on both sides, so two prongs are left which mate with the slots in the nut.
If you look down into the socket side you will further spot similar recesses in the bottom that accept a driver made from a smaller pipe. This one is not strictly needed, but it is always best to have a something to stick into the other hole.
Seems solid state meters are a bit better at consistency (not much to act up on them if they weren't abused), possible to dust off some analog meter with the wire needle on a jewel bearing to see how well it's calibrated? (Not even sure if Clive has something that old.)
Always liked the Fluke meters myself. When I worked at BT that's what we used.
Can't go wrong with a Fluke.
I've had my 88 used professionally since 2003.
I also have the Fluke 23 with big plastic professional looking, high quality yellow plastic and gray vinyl flap carrying case and all the accessories (temp probe, test clamp, and someone's hand fabricated alligator clips). Used on the ebays for $60.00 U.S. Second favorite meter after the Tektronix TX-3. It appears your DIT 400 is only available from the UK. Perhaps I've missed it, but I would love to know what you use as a DC reference voltage source.
We have a chain here in the US called Harbor Freight. They sell mostly very cheap Chinese tools, lawn sprinklers that look like frogs, and tarps, etc.. They often have coupons for free items, and I have got 3 DMM's from them for free. They are amazingly accurate. I would have killed for one when I was a kid.
Uni-Trend stuff is pretty excellent, and awesomely excellent for the cost! Mind you they do some seriously costly "professional" equipment too, especially their range of higher-end digital 'scopes such as their 800 MHz UTD5082C - over $8000 in Australia.
For low-range resistance testing, it can be useful to give the lead plugs a quick squirt of contact cleaner / lubricant. Helps a lot (especially on the cheaper meters with no null capability)
I use a cheap meter all the time. Never fails. I've got a fancy fluke with a detachable screen but it absolutely murders batteries and every time I went to use it it was dead. So I use the cheap one.
I've always been a Fluke fan. In the old days I always wanted a big black Simpson meter.
Bought a basic Fluke 115 about two years ago. Still was about 200 euros.
Even while those aren't made over here anymore.
Fluke factory and development department used to be about 12 kilometers from my home.
When it comes to EMC measurement equipment, calibration is a bit more of a fuzz.
Calibration labs have to be certified specifically for EMC equipment.
Some Schaffner/Teseq equipment even needs to be sent to some lab in Switzerland for calibration and adjustment.
I've encountered a problem with cheap multimeters that seem to use some sort of lubrication for their rotary switch. Over time the lubrication gets smeared all over the contacts on the circuit board, adding a random few ohms in the lower ranges. Disassembly and cleaning is indicated when it gets too bad...
Another great video is there any chance you can do something on pats testers (portable appliance testers) and how to use them, would be great to see, you must have one kicking around somewhere. That would be another great video.
What we now are anticipating is a check of the voltage and current accuracy as well.
It's good to see you testing meters down in my tight-wad price range.... 'specially that you've found them to be "not actually that crap at all"
I finally got a Uni-T 210E ($50.00) after seeing yours after you got it a while back. I really went through some "gosh, do I really need this" sorts of thoughts but went for it. I really like it, mostly for the DC clamp function.
I still use this Aneng AN8002 ($13.00) for most stuff which I got originally because it could measure capacitance. I thought I was having problems with my home AC unit.
It's interesting, like you've done here, to just compare the two. Just now, I'm finding the Cap test pretty much spot on between the two for a couple beefy AC caps. A 35 + 5 uf 440 / 370 VAC one and a 145 uf 330 VAC one.
Now I'm curious to make a little box like you have for testing resistance.
I have one of those little yellow meters, sold in a red plastic case in the United States through Harbor Freight. Unfortunately it has gone out of calibration for AC volts, testing a residential electrical socket, which should net a reading between 115 and 125V, got 145V. Testing with a better meter got a proper reading.
So I basically only use that meter to confirm the presence of electricity, not for what any actual values are.
Yes, it is a common misconception that calibration involves some kind of adjustment. Calibration means comparison with a certified traceable reference (in this case reference resistance). The calibration certificate lists the measured values in a table with the calculated uncertainty of measurement. Not a mere yes or no.
Actually not any kind of pass or fail, unless the equipment has official requirement like the kilowatt-hour meters for electrical energy companies.
My real question when it comes to multi... well with any type of meter is safety first. If I poke my probs across something I believe to be off but it's not, or if I'm doing a voltage test, how safe am I? I've been using a Fluke 381. An old version of it,been considering getting a either the 3000 industrial kit or the 287. I know they should be completely safe. But what about the much cheaper Klein brand multi meters? There hand tools are great, but I don't have any experience with there meters
Which meter in the lower price range would you recommend? I need to test some 18650 cells and maybe for some hobby projects in the future once I found the inspiration
The Uni-T UT210E is very good. It has the extra accuracy and resolution for testing lithium charge accuracy.
How do we know the values of the resistors in the test facilities are still okay? Sure, component values _shouldn't_ change over time, but does that mean they _don't?_ Are there certain physical properties that can be measured that are more fundamental than "that's what the label says"?
I'm not trying to cast doubt on anything, I'm strictly curious.
interesting how auto generated captions tend to pick ohms/ohm up as "dorms", megohm was usually picked up right though.
I'm a spark and never send my fluke/robin 1653 MFT for calibration, I just prove my meter against other meters that have "been calibrated" but the test rig you made is a good idea.
I misplaced my two cheapie yellow meters, the not-quite-so-cheapie black meter I bought with the Cat5 tester has also gone MIA, and like you experienced, the leads to go crap. So a few days ago I went meter shopping at Walmart. The one model in Housewares was overpriced, so I strolled over to Automotive. They had two options, fairly close in price, under the EverStart brand (Walmart's store brand for car batteries). I ended up grabbing one that came with a thermocouple, a nice pumpkin-orange backlight, and I picked this one over the lower-priced unit because it includes the non-contact sensor. The leads insert well, click into place easily, and un-click just as easily. It's rated 300VAC, which is more than enough for my needs.
Now, if I can just find a schematic for my Eico Cortina Sound n' Color color organ, so I can set about restoring it to its former 1970s glory...
I also have the UNI-T and it's a great little meter which I've used many times with current clamp and a very old Fluke 8025B which can be calibrated at home although it was only very slightly out I assume due to it's regular calibration while it served in the RAAF. Fairly big and heavy grey thing but it's my every day use meter.
I missed at least one more insulation tester, the big yellow 4000V AC tester. (Was it an compliance tester?) And haven't I seen another DC insulation tester being used in some previous video?
I think the yellow and black/yellow meters are the same deep down and insulated plugs don't fit...
When you get jittery resistance readings, in my experience the problem often is that the test leads have experienced too many bends next to the probe end or the banana plug end. There are just a few strands left, while the bulk of them are broken and may or may not touch for contact.
In a couple of cases I found that the soldering of the banana jack to the printed circuit board had been stressed too much and had failed.. As the sockets tend to be nickel plated, it was a pain to fix the solder connections, but with good flux and avoiding too much heat on the PCB did the trick and both the meters still work fine.
I would use large 50W resistors for 1R and 10R (and add a 20R and 50R too) so it could be used as a load and will allow you to test calibration of PSU ammeters too.
You must have gone "nuts" building this....
how much worse do the results get when using a higher than needed range?
I own a little yellow DT830B meter and a Fluke 25 that came from the Ministry of Defence in a massive case. I just ordered a UNI-T UT210E.
Got the same Tacklife meter, perfect for little projects too, since it can measure capacitance etc, and also got that contactless voltage sensor, all for 20€ and also feels nice
Hows the flashlight for working in areas like engine bays or in dark-ish places (not pitch black but say sun isnt co operating or etc)?
Would love to also see a tear down of the Robin metre, we also have had one fail at work earlier this year.
I'd have expected more of a variance to be honest. Pleasantly surprised. Do they make good affordable multimeters that measure capacitance and inductance btw?
i love my cheap meter. Having one in the garage is so much easier than having to go upstairs to get my "better" meter
I’ve had my Fluke for 32yrs used everyday for work (blew the fuse only once long time ago) and also have the uni-t clamp mostly used for working on cars searching for parasitic battery draw problems and charging rate
Would it be more accurate to put, say, ten of the same resistors in series so the +/-1% values average out?
bokkenka
Not usually. They tend to be very similar in any batch, so you would have to source them from different batches. The best approach is to measure with your most accurate meter, as Clive has done here, to get a ‘true value’.
i have a time electronics resistance box i bought at a boot sale from an old engineers, with 2 variable psu's for £25. good old fashioned sturdy quality equipment.
I quite like these sort of comparison videos. Do you have an analog MM? It would be interesting to see how it compares in accuracy to the more modern DMM. Also, I would like to see the build video of the resistance reference with resistor evaluation and selection. You could just show installation of one port then jump-edit to them all being installed and describe any difficulties encountered. How it's made seems pretty obvious, but a video may help someone who is just getting into the hobby.
Eddie
Some analog meters, such as the ones with a mirror scale, can do amazingly well.
For testing the resistance ranges, it's best to get precision 0.1% resistors. They're more expensive but are better than 1% resistors when calibrating a meter. Nowadays chips and resistors may be trimmed to close tolerance with a laser, before they are assembled.
Hi Clive, I wanted a Fluke meter, but the official Oz models were too expensive. I found a Fluke for sale on eBay, it was the Chinese market model, not for sale outside China. Of coarse the Chinese seller didn't care. The instruction manual and box was in Chinese, but the scale is in English. I was able to download the English version of the manual. It is a genuine Fluke, not a knock off. I call it my "Fruke" 😄 I have the UNI T also, I really like it.
Anthony Witham Chinese variants may have less disaster protection because China has enough disposable people to risk loosing a few.
I have an old Fluke 73m had it from new in 88. I ran over it with the car. If it had been face up it would have been OK, but face down a piece of gravel cracked the screen, still worked though. Phoned Fluke, they wanted it for their museum of disasters that happen to Flukes and they survive, but they eventually sold me a new screen.
Some applications here in the US we have to send meters in for calibration. Mostly Aviation and things where safety is a huge thing.
I'm interested in how well those chinesium Arduino based rebranded DIY project component testers would fare in this test. Mine seems surprisingly accurate, but I also do not own any accurate meters.
I test the calibration of mutimeters at work for the alarms and security systems industry. We use a calibration kit from ACT Meters. In the kit is a test box for checking Ohms, volts and amps and a multimeter which is externally calibrated in our case, by RS components. I have always thought that this is a bit of a waste of time for digital multimeters because they generally don't go out of calibration. ACT supply a calibration certificate template which states that anything + or - 5% from that measured by the externally calibrated meter is acceptable.
I thought the calibration requirement was part of the TL-9000 standard. We are not allowed to carry a meter with an expired (yearly) calibration into a designated laboratory area whether we plan to use it or not.