0.01% resistors or verified 0.1% resistors wanted - Page 1
Forum section: electronics / general

author: BiOzZ
author_rank: Regular Contributor
timestamp: April 17, 2013, 11:15:18 pm
content: my 2 multimeters i use for everything are out of cal ... i fixed them for voltage but i need current and resistance but 0.01% resistors are expensive if i buy just one of themim looking for someone with 2 or 3 different values of 0.01% (preferably threw hole) resistors or someone who can verify the value of some 0.1% resistors down to a value of 0.01% or around about that value ... properly measured by leaving it in a room with a known tempature for a bit than measuring it without touching itand im looking for both for under $20 minus shippingmy goal values are 1k and 10k and possibly 100k or around about that ... 4.7k ... 15k and 220k or whatever

author: amspire
author_rank: Super Contributor
timestamp: April 17, 2013, 11:41:13 pm
content: Investing in a single 10K Vishay metal foil resistor is worth it and it is just about in your budget.If you have one very accurate resistor, it is possible to make your own precisely calibrated resistors that are multiples of 2 or ten different from the 10K (ie 100, 1K, 100K ,1M, 20K, 5K, etc) by building a Hamon divider and by making yourself a good microvolt galvanometer with a low current low offset opamp.This is an exception resistor for $27:http://www.digikey.com/product-detail/en/Y145310K0000V9L/Y1453-10KA-ND/2609894+/- 0.2ppm/C +/-0.005% accuracy . It should have fabulous long term stability.With the Hamon divider, with care you can multiply or divide the values to at least 0.001% accuracy comfortably (relative to the 10K Vishay). Digikey also have some nice Vishay low temp coefficient Vishay axial resistors for under $1 with a temp coefficient down to a few ppm/C that you could base your secondary references on.If you search the EEVblog for Hamon divider, you should be able to find links to Conrad's site where he explains it all.Richard.Edit: A quick Google search found Conrad's description of the Hamon Divider:http://conradhoffman.com/HamonResistor.htmlConrad seems to be using a Hi-res meter, but all that is needed is a sensitive galvanometer to detect 0V +/- 1uV. Everything else can be done with resistors alone, so you do not need a 6 1/2 digit DMM to get the Hamon divider down in the 1ppm accuracy level.

author: mariush
author_rank: Super Contributor
timestamp: April 17, 2013, 11:44:53 pm
content: I would suggest going for a DMMCheck from Voltage Standard :http://www.voltagestandard.com/DMMCheck.htmlIt's 35 dollars in his online store and has:QuoteYes, it's a bit more than 20$ but it looks like a good deal.

author: BiOzZ
author_rank: Regular Contributor
timestamp: April 18, 2013, 01:30:40 am
content: Quote from: mariush on April 17, 2013, 11:44:53 pmthanks! ... im going to purchase that one soon ... it looks very nice and knowing its calibrated already and not just mass produced is very comforting!i do wish it had a second voltage reference and current source (many voltage references contain an option for 2 voltages) to give a more liner check but for its cost i cant complain!

author: retiredcaps
author_rank: Super Contributor
timestamp: April 18, 2013, 03:38:43 am
content: Quote from: BiOzZ on April 17, 2013, 11:15:18 pmJust of curiousity, what is the make and model of each?

author: ivan747
author_rank: Super Contributor
timestamp: April 19, 2013, 01:08:08 am
content: Quote from: amspire on April 17, 2013, 11:41:13 pmIf you like precision, make sore you also check out Conrad's mini metrology lab. I really like this one and I want to do build one myself. I am most interested in making my own gear (power supplies and this are a good start).http://conradhoffman.com/mini_metro_lab.html

author: casinada
author_rank: Frequent Contributor
timestamp: April 19, 2013, 04:05:59 am
content: I purchased some Vishay 0.01% Metal foil from this site:http://www.ebay.com/itm/1x-11K000-Vishay-RS92N-Series-High-Precision-Foil-Resistor-0-01-11K-/110984367059?pt=LH_DefaultDomain_0&hash=item19d72f0bd3They are used pulls. Each resistor came labeled in a Zip lock bag with the measured value. If you order a few together he can combine shipping (ask).

author: Monkeh
author_rank: Super Contributor
timestamp: April 19, 2013, 10:08:21 pm
content: Those are.. cheap. Tempting, but..

author: nukie
author_rank: Frequent Contributor
timestamp: May 03, 2013, 01:27:13 am
content: Plenty of seconds available from China cheaply, this is one of the most reliable way to get the real parts via eBay. If you could link the seller to taobao.com account and verify the feedback it would be even better. Fake sellers usually get caught quickly. Buy in bulk, verify them electrically side by side. The way the boards are heated during disassembling and reclaiming process is not pretty. Some parts may look OK but they could be damaged internally.Passive parts is okay, try to avoid buying seconds ESD sensitive parts, not worth the risk.

author: AlfBaz
author_rank: Super Contributor
timestamp: May 03, 2013, 02:03:07 am
content: Quote from: amspire on April 17, 2013, 11:41:13 pmThis LTAN42has similar examples and a good blurb on precision trimming