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- Опубликовано: 21 окт 2024
- An impromptu play with Dave's Wekomm 10K Transfer Resistance Standard.
What is the strange discrepancy in drift on the graph on the Keithley DMM7510 multimeter?
www.wekomm.de/m...
This is Part 1, don't forget Part 2 is here: • EEVblog #835 - Wekomm ...
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![FNAF vs TF2 - Episode 2 [SFM]](http://i.ytimg.com/vi/z5b3V2-VLb0/mqdefault.jpg)
I just watched a 25 minute video about a resistor.
Not disappointed.
+LazerLord10 There are two parts!
EEVblog
Yay!
+LazerLord10 Was the word "metrology" already in your vocabulary?
john smith
No, but it is now!
Same here. At least, I've watched it at 2x speed...
Still too slow. RUclips should have a 3x option.
"Just a quick little video." Lasts 24mins. Never change Dave!
+Thomas Kell And then we have part 2 (private at the moment :( )...
+Thomas Kell It was seriously meant to be a 2nd channel video just showing that first graph. I got hooked...
+EEVblog While i was at it i wanted to ask if you would be interested in tearing down a Nintendo Virtual Boy. It was a total commercial failure so it's somewhat of a novelty item at this point. However i do have a spare one that turns on but it has a busted LED which is mostly due to the poor choice of glue they used to fuse the ribbon cable with. If you are interested i'll send it down to you. And as always, thanks for the great content!
+Thomas Kell Sure!, thanks, send it into the mailbag.
It would be interesting to compare it with a normal 10k resistor
Very interesting stuff. Some viewers might think "that's nit picking". Well, try to measure temperature with a resolution of 0.01K using PT100 while the PCB itself could be at media temperature or room temperature. So the reference resistor of the PCB could be anything from 15°C to almost a 80°C while measuring hot water. All of a sudden these things become very important and in my case I found myself purchasing single resistors for almost €10 per piece and resistor networks for like €45 per piece. Otherwise the circuit would be 0.1°C out.
"A quick little blab video". 25 minutes later on to part 2 . . .
Gotta love it!
+Bigrignohio I got hooked, couldn't help myself, the data just kept flowing...
Don't forget, thermals, temperature change, I would use special leads, Twisted Silver Plated Copper (PTFE) with outer Silver plated copper screen to guard on DMM, with Copper connectors (Crimped) NOT any solder as this can cause thermals, Also remember their test current used in their test, I am a retired Calibration Manager of UKAS Laboratory where measurements were often in
I wonder if barometric pressure is having any effect, possibly explaining the initial small dip in resistance when the ac was turned on.
+pocoapoco2 I have done a similar experiment (but then with a LM399) and logged the pressure too and that made a difference. (Even the level-angle deviation of the reference made a difference) I held the inside of the meter at a fixed temp.
Dave: a rather expensive setup to measure your lab temp :-) and indeed, it can keep you busy for weeks.
Nice Video.
I wish I could get this much enjoyment out of a resistor... maybe one day
Dave, I guess the fluctuations of the graph may be due to the Air-Conditioner's PWM (On and Off to control the temperature). If your Air-Conditioner is inverter based you will not see these fluctuations of the graph.
Dave, did you control for the 37C hot air source in the lab? ;)
Would be interesting to see how much the internal voltage reference in the meter is drifting vs exterior temperature. I say this because those results seem to be happening too quickly to saturate the metal/case that the resistor sits in, but not for a fan blowing air through a meter.
Those people are a long way away from the "superb" construction of a certain voltage reference the people on Dave's forum know and love.
Part 2 is private. You gotta set it (at least) "unlisted", if you want it watchable :)
+Tim Engel Come on Dave this is exciting stuff! We need part 2...
Just get the dam tripod! great vid! Thanks!!
I was just given an old multimeter for christmas, and boy could it use trimming. Could I borrow that resistance standard for a few minutes? ;-)
+EEVblog Correct me if I'm wrong here, but isn't 2.5ppm = 0.0000025? (five decimal zeros). You got it down as 0.000025 (four decimal zeros) on your post-it. ∆ of four degrees would be 0.0000100 then.
Wouldn't that mean it might be at least a lot closer to being out of spec?
Datasheet around 19:40 mark.
Thanks Dave, I'm working the same type of measurements on a voltage reference and resistors with my 34401A.
So I have 2 questions.
1. I hear a fan, does the Keithley run a fan? If so the ambient temp may change faster with the fan forcing the air through the the meter to coincide with the air temp of the lab.
2. Does the LCD turn off as a screen saver on the Keithley? If yes this might also justify some of the temp coefficientcy change with the meters internal components.
+Dave B.Reviews (My Gadget Tech Thoughts) Yes, it has a fan. No screen doesn't turn off.
ha, still a protective cover on the multimeter screen
That's a fancy thermometer you got there.
+Dr_Kachu san It works!
I don't understand this video but it was still enjoyable!
not very often im here this early :)
What happens if you log a dead short using the Keithley over time?
^WHS
Dave, didn't you heat it up too much by any chance? I mean, the ratings on the front say V max = 20, and A max = 0.01, giving a max dissipation of 0.2W while the Keithly is talking about a 4W resistance measurement....
Lol 1 dislike when the video hasn't been up long enough to watch most of the video
+MicrowaveMeShow I bet it's Batterizer
+MicrowaveMeShow It happens on my channel too.
+The Signal Path Blog When you reach a certain audience number you get the serial haters. Congrats!
+EEVblog it should make you feel even better that they are probably subscribed too. so you really can't lose out!
***** Lol I had to look up what you were even talking about and go stick a soother in it you huge baby
I noticed with your recent multimeter teardown that you don't seem to pull off the factory screen protectors. Is that just a thing you do?
+Tb0n3 It annoys people, and I kinda like that :->
I have a 29 year old Iwatsu oscilloscope that still has delivery plastic on the handle. At this point I don't want to take it of just to preserve the history.
When you left you took with you your body which emits about 0.1kw of heat energy. Could that make a difference?
My thoughts would have been towards the meter because of the last part of the graph was clearly showing an active element to it which the passive resistor wouldn't have. The Graph was showing an up then down then up then down as it was climbing.
Also to add to this idea, the spikes may have been due to power surges when the aircon went on and off, the lights too would produce surges that at the resolution the meter was working at would be visible. .
+Michael Hawthorne In this case the spikes are not the aircon (but that's not uncommon in gear). The spike happened right when I bumped the bench.
Dave, I think you were off on your meter error calculation by an order of magnitude, 2.5ppm is 0.0000025 (5 zeros after decimal point, you only had 4), so would be .00001 over 4 deg drift, about 6 times less compared to the diff you noticed in the measurements so not clear if that was the meter, unless I got something wrong
EDIT: never measured this but would be interesting to see relative measurements with the leads shorted over the same temperature range, might be interesting to see if that's where the difference comes from.
+sharp x 2.5ppm is 0.000025 Kohms. You have to scale it for the 10k resistance.
EEVblog
ah, duh - brain fart on my part (rimes too :)
btw, can you help me validate my eevblog account, the validation email never makes it in my inbox (or junk mail for that reason).
+sharp x You had me worried for a minute, I had visions of having to recall or annotate the video! Send me an email with username
EEVblog
username is sharpx, don't know your email.
sorry about the ppm, I was going by delta, didn't clue in the spec was for the 10k range until you mentioned it.
interesting that it isn't a temperature controlled reference like TCXO or OCXO.
Hunting the smoking gun, its a good one dave :-D
I also suspect the meter drifted with room temprature, putting the resistor in a controlled chamber will show how much the resistor added/subtracted.
I still think the result would have the same pattern :-)
Never heard Air-con until now... Took a while to figure out what you were talking about.
+ophello Air-con is air condition :)
+ophello Oh those Fancy Pantsy Aussies. We're not all formal like "Air-Con" in the US, it's just "AC".
+ophello It's just the return flight of Con Air...
BFX chanel Yeah, that's why I said "took a while to figure out what you were talking about." That implies that I figured it out on my own.
+stonent In an electronics lab, at least in oz, AC usually does not mean Air Con.
In Edison's lab maybe...
Thought you would run tests at STP. Maybe graph the temperature and see if they match the test results. Also you are down under so maybe you have to invert your results ! Thank you for another great video ! tjl P.S. Over at Case Tech in Ohio some poor guy tried to prove that there was an ether by proving that the speed of light varied; He could not, so he felt that he failed and was a failure.
+Tim Lipinski
If you're speaking of A.A. Michelson I dare say the Nobel prize assuaged his disappointment somewhat.
:-)
So, It's close enough then? :-)
I got up today and my "lab" (livingroom) is 13°C.
9.999968 ?!? Too far out!!!!! ;)
Joking aside... That's impressive. Also very interesting. Would the ramps while cooling down be due to the action of more heat being dissipated in the resistor body as the resistance increases due to ambient temperature?
Correct me if I'm wrong, but it's out by 0.06 ohms?
you're wrong. more like 0.00006 ohms in the worst case.
3:55 It says 10 mΩ/div. You don't have to download data now. ;-)
could it have something to do with the pull of the moon and the tides!?
the finest aged resistor
Why would anyone need such a high precision?
* stability
Looked up the price of the Keithley, GULP!!
So, 47000 people have watched a video about the accuracy and stability of a "resistor", more than 1200 people "liked" it, and more than a hundred people were moved to comment on it.
I'm not currently getting any sex either, but jeez.......
But the price of Wekomm RS9010A is way too high.
Barometric pressure?
Hi, Dave
+kolby4078 Hi!
So i am a recent new viewer and I was wondering what does save as a job besides RUclips. Or is he full time youtuber
+Jaime Cernuda Mostly RUclips, and some board design as contract work.
+Jaime Cernuda RUclips has been my full time job for 4 1/2 years now.
+EEVblog Nope, haven't done contract work for 4 year now. RUclips and associated ads and dondations etc (and uCurrent sales) is my only income
+EEVblog congratulations on that full time dedication to what you like must be awesome. Thank you for your answer and till the next video :)
As a technician, even fixing a wide range of gear, I can generally do my job professionally with just seeing if a resistor is open circuit or not. I don't need this out of spec by 0.00047% and this parts per million per degree rubbish! :-)
+Alan Liefting open circuit or not, that's a pretty wide tolerance!
Is there a colour band for that?
+Alan Liefting You're not the target audience for this type of test gear. The people who have to care about this stuff are the designers of scientific instruments like electron microscopes
Josh Bradshaw yes I realise that. And I just wanted to throw in one of Daves phrases! :-)
doses not let you watch part2
last night was near a full moon so maybe the lunar pull of gravity affected it!
“...only using my Keithley 7 1/2 digit meter...” and it’s not good enough! Haha...I’ll take that piece of junk when you want to get rid of it.
Well waffel on :-)
!
193 th viewer
first