vishay precision resistors - DMM check - Page 1
Forum section: electronics / projects

author: Homer J Simpson
author_rank: Super Contributor
timestamp: January 20, 2013, 08:29:49 pm
content: In one of Dave's videos, (can't remember which one), he has a small project box with a couple a precision resistors that he used to test DMM calibration.I want do do the same. Obviously this is not a "Lab Standard" or anything but it would be good enough for me.I would like to use Vishay precision foil rated at .01%.Would 2 values be good or should I have 4?What about the values of the resistors themselves? What would be a good spread to test accuracy on the DMM?Thanks, KT

author: retiredcaps
author_rank: Super Contributor
timestamp: January 20, 2013, 08:36:50 pm
content: EEVblog 374 - DIY Multimeter CalibrationStart at 7:46 of the video where he has close up of part numbers.

author: SeanB
author_rank: Super Contributor
timestamp: January 20, 2013, 08:53:46 pm
content: Normally values that are near the end of the DMM resistance range, ie 100k, 10k, 1k and 100R, or 200k etc. Try to use a wide range of resistors, more is better.I have a board with some 221k 0.1% and some 676.98R 0.1% resistors on it. Place a few in series so you can have a wide range from a few resistors, along with a few steps of known value to check linearity.

author: Homer J Simpson
author_rank: Super Contributor
timestamp: January 20, 2013, 09:36:08 pm
content: Her are the Vishay .01% foils I would like to get.http://www.mouser.com/Passive-Components/Resistors/Metal-Foil-Resistors/Metal-Foil-Resistors-Through-Hole/_/N-8elfo?P=1z0srt3Z1z0t6d0&Keyword=precision+resistor&FS=True&Ns=Resistance|1Not cheap. $15 TO $50 per resistor.Would their be a benefit to getting an odd value to help test accuracy? For example, instead of 50k get the 57.983k?Thanks

author: grenert
author_rank: Frequent Contributor
timestamp: January 20, 2013, 10:10:46 pm
content: If you're looking to save some money and would also like a bit of convenience, you can buy a set of precision wirewounds from 1R to 1M (0.01-0.02% tolerance, not sure the tempco) in a plastic enclosure from here:http://www.precisionresistor.com/MC-7-Calibrator.html$67, not sure what shipping costs.

author: Kevin.D
author_rank: Frequent Contributor
timestamp: January 20, 2013, 10:22:24 pm
content: Years ago I got 2 packets (25 in a pack) of .01 % precision wirewound/metal foil 12k5 and 25k resistors that I got for £1 a packet from one of those excess component places that used to advertise in the hobby electronics mags here in the 80's.(Marco trading or Greenweld electronics ).I haven't been able to identify them though ,they just give the value , the tolerance and a number '8917' or '8910' then the manufacturers name which has been blotted out . maybe this means rejects cause they where slightly out of spec. ? They come in handy though for rough checking meter calibration. I found some on the web that look very similar and they where being sold for like £9 each resistor .

author: (In)Sanity
author_rank: Regular Contributor
timestamp: January 21, 2013, 04:38:44 am
content: Keep in mind they are most repeatable when used at the same temperature. Personally I would just go with a very low temperature coefficient resistor and have it measured on a precision meter such as a 3458A, that way it'll be good for checks on a more frequent basis. If however we are talking about just a quick test on a 4000 or 6000 count meter, then your just fine going down the road you are thinking. I have an HP 3457A and I'm sooo glad I don't have a 3458A as it would drive me even more nuts with the guest for precision parts.It's cheaper to get one from voltagestandard.com, already measured.Jeff

author: edavid
author_rank: Super Contributor
timestamp: August 12, 2013, 04:07:40 am
content: Quote from: Homer J Simpson on January 20, 2013, 09:36:08 pmArrow currently has a few values on sale:Y00891K50000TR0L 1.5K 0.01% $2.35RNC90Y7K6800VR 7.68K 0.005% $6.27Y00628K90000T0L 8.9K 0.01% $4.16Y000755K6000T0L 55.6K 0.01% $4.10RNC90Y75K000TR 75K 0.01% $5.25

author: Lightages
author_rank: Unknown
timestamp: August 12, 2013, 05:21:51 am
content: There is also the consideration that many multimeters now can be calibrated/adjusted with either a "secret" turn on method or with proprietary software. These methods require specific values and therefore it would be better to buy these specific values if you wish to make these adjustments instead of just checking the accuracy of the reading. For example the Uni-T UT71X series require 190 ohms and the decades of this value. Some Brymens use decades of 250. The UEi DM397 uses decades of 40 ohms.If you can, find out what are the values needed for your particular meter from the manufacturer if they will divulge the information.