WANTED (UK): voltage reference  - Page 1
Forum section: electronics / general

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 29, 2017, 02:57:41 pm
content: I'm looking for a voltage reference, preferably 10v, which is in working order. I'm hoping someone has a spare which they would be willing to sell. This is for hobby use, so I don't exactly need a ltz1000 based design, although I wouldn't say no to that.Please PM me if you have one to offer.

author: tggzzz
author_rank: Super Contributor
timestamp: October 29, 2017, 03:01:23 pm
content: There are many things on fleabay that match that (lack of) specification.

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 29, 2017, 03:09:38 pm
content: Fair point. My reason for posting the request here is that I have more faith in Eevblog forum members than I do in online auction sites.I'm looking for an assembled 10v reference, not just an IC , which has gone through its burn in period and is known to be stable. I'm refraining from being overly specific in order to cast as wide a net as possible.

author: tggzzz
author_rank: Super Contributor
timestamp: October 29, 2017, 03:18:18 pm
content: So you think a 10V reference is a solution to your (unspecified) problem.Read the second and third paragraphs athttps://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/Edit added: Alternativelythis fleabay devicewill give you a 10V output that completely satisfies your stated specification.

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 29, 2017, 03:21:15 pm
content: I'll go take a look.My request stands. If anyone has a good old 10v reference they would like to sell, please get in touch.

author: Zucca
author_rank: Unknown
timestamp: October 30, 2017, 09:58:59 pm
content: HiBNElecEng, I am not an expert about 10V voltage reference.I am following those dragons in the metrology section and it is hard. I have basically this problem: so many graphs, specs and number and all I want is a solid rock DC reference (what ppm/year or ppm/°C? he he). Guess what... The more I read the more I learn from them, it is amazing. Did you try to jump in EEVBlog metrology section with a good cup of cofee?That said there is so much I can learn by building a voltage reference. I already have a KX reference to play with...https://www.eevblog.com/forum/metrology/kx-reference/I like to waste my time to help somebody. Please don't buy a cheap PSU from devilbay, it is not a DC reference.EDIT: Just found something very interesting...https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg1336573/#msg1336573

author: BNElecEng
author_rank: Regular Contributor
timestamp: October 31, 2017, 08:20:32 pm
content: Thanks zucca. I've been reading a lot of interesting information in the metrology section. I'm amazed at what they have been able to achieve.I'm planning to order some kx reference boards for the lm399 from OSH park, since it'll be within my budget and I can try different things with each reference to see the effect.How long have you had a ltz1000 kx reference for?

author: Terry01
author_rank: Frequent Contributor
timestamp: October 31, 2017, 10:29:49 pm
content: Hi buddy.I got one of the £5 eBay ones purely for hobby stuff,and I was curious. I have the Brymen 867s meter that goes to 500,000 counts resolution and the fluke 177(and a couple of others too), the reference was spot on at 10v,7.5v,5v and 2.5v so they are near enough. I think from memory on the Brymen the 7.5v was 7.499xxv or it was the 2.5v that was a whisker out,either way good enough.After getting these results I saw a video on YouTube that said the ticket you get with the reference stating its been checked on a 6 1/2 digit bench meter is a load of waffle and just a printed ticket. It's a "DOH" moment when you think about it so it boils down to its all lies anyways!I think my meters may have been in on the joke LOL

author: Mr. Scram
author_rank: Super Contributor
timestamp: October 31, 2017, 11:58:49 pm
content: Quote from: Terry01 on October 31, 2017, 10:29:49 pmI've seen some people doing interesting analysis of the numbers provided and currently measured numbers. Some do seem to be made up, as they don't correspond to the actual numbers in any coherent fashion. However, in many cases the numbers have drifted in similar ways across the range, which indicates that they were actually measured by someone before shipping. So, there's a chance of foul play, but a decent chance you'll actually get what is promised. Better yet, you can pretty much check for yourself.In short, getting a $3 to $20 reference on eBay is a great start. From there, you can always decide to get fancy.

author: exe
author_rank: Unknown
timestamp: November 01, 2017, 04:28:50 pm
content: Quote from: Mr. Scram on October 31, 2017, 11:58:49 pmOne more datapoint. I bought one of that voltage references (with 2.5/5/7.5 and 10V outputs). Mine is bang-on (compared with my "new" Keithley 2000) except for 5V: it measures 5.0009 instead of 5.0006. May be it was a typo. Overall, more than enough for an average hobbyist like me.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: November 01, 2017, 05:01:03 pm
content: Quote from: BNElecEng on October 29, 2017, 02:57:41 pmMytravelling mini-referenceshould be available soon for a couple of weeks to use if that is of any help. It will be freshly measured on the HP3458A Opt 002.CheersAlex

author: tggzzz
author_rank: Super Contributor
timestamp: November 01, 2017, 05:15:29 pm
content: Quote from: Alex Nikitin on November 01, 2017, 05:01:03 pmI finally feel in a position to make use of it: my Solartron 7081 seems to be respectively stable. Hence, when convenient, I'd like to use it.There's no hurry; perhaps it would be best to avoid getting caught up in the Christmas postage rush.

author: Mr. Scram
author_rank: Super Contributor
timestamp: November 01, 2017, 05:22:53 pm
content: Quote from: Alex Nikitin on November 01, 2017, 05:01:03 pmTravelling as in shipped to various people to check their gear? That might interest me.

author: BNElecEng
author_rank: Regular Contributor
timestamp: November 01, 2017, 06:10:44 pm
content: Thanks to everyone for their responses. I've bought one of the cheap Ad584 references as a starting point, since they are easily available.Alex, thanks for the offer of your travelling reference. I don't think I'm quite ready to make good use of it. I only have a keithley 195A to start trying to measure with and I've got a Prema 4000 on its way to me. Perhaps in a few months if you don't mind?