hybridfree/eevblog-posts huggingface dataset:
One Year Drift Plot - Page 1
Forum section: electronics / general

author: wn1fju
author_rank: Frequent Contributor
timestamp: June 03, 2017, 04:30:00 pm
content: Here's the result of a one year measurement of typical drifts one might expect in a basic home setup. Before you guys get upset, I fullyunderstand that this is NOT metrology-grade.I took monthly readings of a Malone VREF10-003 (30 ppm) 10V reference against an HP 3456 6-1/2 digit and Advantest R6871E 7-1/2 digitDMM. The equipment was left off except for a two-hour warmup once a month when I made the measurement. The measurements weredone by averaging the results of 5 pairs of readings, each pair yielded (x - y)/2 where x = leads in normal position, and y = leads reversed. Thesame test leads were used throughout.The graph shows the ppm error off of the nominal 10V along with the approximate temperature in the lab. The temperature was offset by60 degrees so it would plot on the same axes (i.e, a plotted value of 4 means 60+4 = 64 deg F).Of course, since the Malone reference could be drifting in addition to the two DMMs, it's hard to reach a definitive conclusion. But, feel free toweigh in with your conclusions (other than I need to get a calibrated 1 ppm-class reference)!

author: Kleinstein
author_rank: Super Contributor
timestamp: June 03, 2017, 05:36:52 pm
content: There seem to be quite some correlation fo the temperature and the difference between the two meters. So at least one of the meters seem to show quite some TC.Hard to seen much more from those data.To see more it might help to have data over a slightly larger temperature range. This way one could get a correlation coefficient or curve and correct the rest of the data accordingly.Just turning on the DMM for a few hours is not long enough to establish a stable humidity level. So it is not a surprise the 2 meters behave slightly different. The high grade meters are usually made to run 168 hours a weak. There can be a few 10 ppm of drift for the first day or so you turn the meter on after a month of storage.
Does Vishay calibrate their precision resistors before selling them? - Page 1
Forum section: electronics / general

author: nour
author_rank: Frequent Contributor
timestamp: May 29, 2017, 07:51:11 am
content: I want to buy some precision foil resistors from Vishay and I was wondering, do they calibrate resistors individually before sending them to customers if not, Can I ask them to do so?

author: TiN
author_rank: Super Contributor
timestamp: May 29, 2017, 07:58:40 am
content: You can ask them to do it, but you are unlikely ready to pay for it (hundreds $$$USD.Or try your luckwith FSRwhich can come with calibration to 10ppm.

author: nour
author_rank: Frequent Contributor
timestamp: May 29, 2017, 08:04:25 am
content: So basically they don't do it, I thought if I pay 500$ for some resistors, I wouldn't need to Calibrate them later

author: Cerebus
author_rank: Super Contributor
timestamp: May 29, 2017, 08:10:11 pm
content: I forget what Vishay call the service, but they have agents in a number of countries that will trim Vishay foil resistors to order. You can order arbitrary values and arbitrary precision. I don't know if they offer explicit traceability on these, but you can be pretty sure that if you order a 1k234 at 0.05% you'll get what you asked for.I looked it up, they call them precision centres, see:www.resistors4u.com

author: nour
author_rank: Frequent Contributor
timestamp: May 29, 2017, 08:57:54 pm
content: I have two main groups, one for some precision resistors that I will use as my lab standard (basically 1K,10K)--> this one I need it to be calibrated up to 6 digits or if possible more. The other group will contain also some matched precision voltage dividers and other individuals that I want to use to build a voltage ref.

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 30, 2017, 12:18:53 am
content: I orderd my 3 VHP101 resistors with an "certificate of accuracy" from vishay. The certificate contains the values of the three resistors. Unfortunatley, without any information about the uncertainty.

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 30, 2017, 12:27:26 am
content: Quote from: cdev on May 30, 2017, 12:23:26 amI ordered 10ppm tolerance. After a few days, they told me that they can't sell 10ppm tolerance (which was possible as I ordered some VHP101 at work). At this point I already paid the resistors. Therefore, the compromise was to sell 50ppm tolerance and include this certificate.
-83 - Page 1
Forum section: electronics / general

author: zhtoor
author_rank: Frequent Contributor
timestamp: June 18, 2017, 03:13:31 pm
content: -

author: Kleinstein
author_rank: Super Contributor
timestamp: June 18, 2017, 04:32:26 pm
content: It looks like the µA728 might be an early buried zener, maybe the the first. It looks like it got replaced by the LM399 for most part and was not used very much.Different from the LTZ1000 / LM399 the zener and diode part are stilt with a diode connected transistor and not using a ref amp, with the transistor used as the first stage of amplification.The concept of having two current sources and thus a nearly floating reference has some interesting aspects, however it also means a relatively high power dissipation in the chip, which is not a good start for temperature regulated chip.

author: Kleinstein
author_rank: Super Contributor
timestamp: June 18, 2017, 05:15:10 pm
content: It might be a product that had problems, like with the cases or with a special process needed to make the zener. Patent problems are another possible reason for not selling a product.With such old, special parts data-sheets are sometimes rare. It may not even made it to the normal marked.

author: Gyro
author_rank: Super Contributor
timestamp: June 18, 2017, 05:34:23 pm
content: Quote from: zhtoor on June 18, 2017, 04:39:32 pmObviously used a lot in Synths...http://www.ebay.co.uk/itm/Fairchild-UA726HC-VINTAGE-SYNTH-MiniMoog-Roland-System-100-SH-1-Korg-Trident-/322548545231?hash=item4b196436cf:g:2tIAAOSw-3FZK8pI
ebay seller of used (aged?) voltage references and other precisione components - Page 1
Forum section: electronics / general

author: not1xor1
author_rank: Frequent Contributor
timestamp: May 14, 2017, 07:28:13 pm
content: I hope this is not inappropriate.A couple of days ago I received several voltage reference ICs (AD588BQ and AD587JK) from the ebay shop hifi-szjxic.According to my limited knowledge and instruments all the ICs are genuine and within specifics with the exception of one AD587JK which was DOA, but the seller promptly accepted to refund it via paypal, so he/she is probably quite reliable (currently 99.7% of positive feedbacks).It looks like hifi-szjxict has many different kinds of used voltage references and precision resistors (and other components).BTW I've no relation (apart a single purchase, so far) with the seller.I hope this piece of information might be useful, if it is not appropriate please let me know and I'll delete the message(can a member delete his own posts? I'm new here).Thanks

author: saturation
author_rank: Super Contributor
timestamp: May 15, 2017, 01:35:32 pm
content: So long as the disclosure is truthful, they clearly state they are used, there is no problem.Used ICs are a common eBay parts item, you can google many stories about a cottage industry in many countries of folks salvaging parts. Used references can be excellent, they are pre-aged and should give much better long term performance. The only problem is the method they use to reclaim parts can be brutal, or not. YMMV. You'd have to thoroughly check the parts.http://www.cnn.com/2013/05/30/world/asia/china-electronic-waste-e-waste/

author: Cerebus
author_rank: Super Contributor
timestamp: May 29, 2017, 09:03:57 pm
content: I bought some used 10k Vishay S102 resistors from the same vendor. They came quickly, they were well and carefully packed, they'd clearly been carefully removed from whatever they were from and, more importantly, were still electrically well within original specification.
Volt-nutting a KE 230 - Page 1
Forum section: electronics / general

author: VintageNut
author_rank: Frequent Contributor
timestamp: May 24, 2017, 02:45:15 pm
content: Recently, I picked up a KE 230 for USD$200-ish. The unit was advertised AS-IS.After a multi-day warm-up the unit is being measured with a KE DMM7510. The 230 is set to output 10V.The measured statistics areAverage: 10.000911Std Dev: 248.5 uVReadings: 396,000NPLC 5So, the stability is about 25ppm RMS while my 731Bs are typically 0.X ppm stable in the same rack over the same temperature range.I am wondering what can be done if anything to make the PWM circuit more stable. Suggestions are welcomed. I have never delved into a PWM voltage generator.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 24, 2017, 03:22:58 pm
content: Quote from: VintageNut on May 24, 2017, 02:45:15 pmAFAIK, the 230 does not use PWM, but a DAC chip with an internal reference (DAC80). The reference is supposedly a buried Zener but it is possible that what you observe is the reference drift/noise.CheersAlexP.S. - the DAC80 chip allows for an external reference connection, perhaps LM329 or even LM399 can be used to improve the performance.

author: Marcus_S
author_rank: Contributor
timestamp: May 24, 2017, 03:49:28 pm
content: Hi,I think this looks a bit noisy as I found my K230 to be much more stable (seehttps://www.eevblog.com/forum/testgear/micro-review-keithley-model-230-programmable-voltage-source/msg955141/#msg955141). But for very best stability the K230 likes a well controlled environment, approx +/- 0,2 °C. My K230 lives in a shelf with some free space in the back. But if the HP66332A in the neighbourhood switches on the fan the air in the back of the instruments gets a little warmer and the signal of the K230 changes in the ppm range...Best regardsMarcus

author: VintageNut
author_rank: Frequent Contributor
timestamp: May 24, 2017, 05:53:46 pm
content: Quote from: Marcus_S on May 24, 2017, 03:49:28 pmI read your thread. Nice job of reviewing the 230.Your stability graph is just a few minutes. My measurement of stability is much longer. And, no way I can control the temperature in my home/office.You should try a 24-hour stability measurement.
[ANSWERED] Voltage sensor to Arduino - Page 1
Forum section: electronics / general

author: gabrielcassio
author_rank: Newbie
timestamp: May 14, 2017, 12:46:02 am
content: Hi everybody, I'm new to this forum, however I think it's possible to have my doubts answered.I'm trying to measure the voltage of a battery (around 45V), however I wouldn't like to use a voltage divider with resistors, because the voltage for the analog input of the Arduino will have the same ground (GND) of my battery, and this is my concern. Other importante point is to use less components as possible. So my questions:Already has any IC to do this kind of measure? Or is there a way to use the voltage divider with resistores with an isolated amplifier?Thank you so much.

author: ap
author_rank: Frequent Contributor
timestamp: May 14, 2017, 07:13:00 am
content: First of, you are better of in the projects section, not here in metrology.Secondly, if you need isolated grounds, you need an isolation amplifier. TI e.g. offers those cheaply. Or you get one cheap in a module elsewhere (ebay...). Some type of divider will be required. But again, get your comments in projects/designs.

author: Andreas
author_rank: Super Contributor
timestamp: May 14, 2017, 08:47:12 am
content: Hello,of course he wants to have a minimum 6.5 digit solution here in this section.So I recomend the HP34401A which has a galvanically isolation as "IC".Connection can be done by the RS232 connector in printer mode.with best regardsAndreas

author: gabrielcassio
author_rank: Newbie
timestamp: May 14, 2017, 07:06:08 pm
content: Thank you ap about your comment. And sorry about the worng placement of this topic.I will post it again, with other point in that section of projects.And thank you Andreas with your comment, I'll look for that too.
Cheap gold plated copper test clips? - Page 1
Forum section: electronics / general

author: splin
author_rank: Frequent Contributor
timestamp: March 01, 2017, 04:40:45 pm
content: When I say cheap I mean cheaper than these Mueller hook clips at £6.52 each:http://uk.rs-online.com/web/p/hook-clips/7148134/That is too expensive given I want to make up a number of sets of test leads. I suppose I could perhaps use cheaper for most leads and only use the Muellers for one pair but it would be easier to manage if they were all the same.Also hook clips aren't particularly robust - either the plastic melts if you accidently put too much current through them or the hook breaks if it has been bent a few times.Hirschmann make some with gold plated bronze contacts and gold plated Berylium copper banna sockets but I can't find any with gold plated copper contacts.Has anyone found any decent quality Chinese clips? Many are dirt cheap but rubbish; more expensive ones may be equally rubbish with bigger profit margins.

author: MK
author_rank: Regular Contributor
timestamp: May 13, 2017, 09:41:36 pm
content: I took a punt on some decent looking four terminal chinese clip pairs, but a quick file in an inner portion showed they were brass underneath and not hard copper.

author: tablatronix
author_rank: Regular Contributor
timestamp: May 13, 2017, 10:07:12 pm
content: I am no electroplating expert but i think gold on copper requires an intermediate plating like nickel so they are probably more expensive or harder to find, also might not be the right springyness with copper base fwiw

author: MK
author_rank: Regular Contributor
timestamp: May 14, 2017, 10:21:21 am
content: Quote from: tablatronix on May 13, 2017, 10:07:12 pmAll true, but they were advertised as "Copper" clips, that is what annoyed me, but they are adequate for general purpose measurements so not totally wasted.

author: tablatronix
author_rank: Regular Contributor
timestamp: May 14, 2017, 01:58:39 pm
content: I know banana jacks are typically copper beryllium alloy. Maybe that is what they were, it is typically used and can be plated with gold.

author: MK
author_rank: Regular Contributor
timestamp: May 14, 2017, 03:47:20 pm
content: The colour was definitely brass and not beryllium copper.
Anritsu 22NF50 open/short calibration coefficients - Page 1
Forum section: electronics / general

author: Bud
author_rank: Super Contributor
timestamp: May 11, 2017, 02:13:41 am
content: Does anyone have the calibration coefficients for the Anritsu 22NF50 Open/Short VNA calibration standard ?https://configure.us.anritsu.com/catalog/i/22NF50

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 11, 2017, 03:30:33 am
content: Each individual open/short will have its own unique cal coefficients.

author: Bud
author_rank: Super Contributor
timestamp: May 11, 2017, 04:09:54 am
content: I do not think Anritsu would go into trouble of characterizing individual standards for a commodity grade VNAs. HP did not do that.

author: TheSteve
author_rank: Unknown
timestamp: May 11, 2017, 06:18:22 am
content: Does Anritsu even recommend the use of the 22NF50 for VNA's? I thought that only sold it for scalar use.

author: chris_11
author_rank: Contributor
timestamp: May 11, 2017, 07:13:10 am
content: With the outside screw terminals you will need an additional adapter anyway, so I do not see much benefit in accurate delay parameters. You can get those using another cal set with known delays and make a comparison.

author: Bud
author_rank: Super Contributor
timestamp: May 11, 2017, 12:55:01 pm
content: This is for measuring DUTs with N-female ports, so no external adapters needed if i understood your comment correctly.

author: chris_11
author_rank: Contributor
timestamp: May 11, 2017, 02:53:15 pm
content: Here a bit about calibration cal kits.http://www.cel.com/pdf/press/TRL.pdfShould be possible with your Anritsu too.
Measuring Coulombic Efficiency - Page 1
Forum section: electronics / general

author: Muxr
author_rank: Super Contributor
timestamp: May 10, 2017, 03:17:53 am
content: Not sure if this is the right section to post in, but I figure it's appropriate (mods please move if not).Jeff Dahn one of the pioneering developers of the lithium-ion battery (a good candidate to interview on Amp Hour), gave a really fascinating talk on Coulombic Efficiency in lithium-ion batteries. It is basically a measure which can help determine how fast a particular battery is oxidizing and ageing, and therefore it can accurately predict the lifetime of the said battery.In order to measure Coulombic Efficiency they had to construct precise temperature chambers and use a heap of Keithley current source meters SMUs and high precision bench DMMs. Skip to 25 minute mark if you'd like to just see the installation part. But I recommend the whole talk.

author: mimmus78
author_rank: Unknown
timestamp: May 10, 2017, 06:30:45 pm
content: We found someone using more Keithleys than Tin in one experiment.Inviato dal mio Nexus 6P utilizzando Tapatalk

author: Vgkid
author_rank: Super Contributor
timestamp: May 11, 2017, 12:57:07 am
content: Video is unavailable. What search terms should I toss to yt .

author: Muxr
author_rank: Super Contributor
timestamp: May 11, 2017, 01:17:15 am
content: Quote from: Vgkid on May 11, 2017, 12:57:07 amOh bummer.. here is a similar talk he gave:Here is a shot of the gear.. more SMUs and Keithley 2002s than even our Tin has

author: BravoV
author_rank: Super Contributor
timestamp: May 11, 2017, 04:40:32 am
content: Thanks for the video Muxr !The 4 volt max exposure, made me think to mod my charger for for certain appliances that need long life li-ion cell.
Yet Another 3458A  - Page 1
Forum section: electronics / general

author: CrazyTiger
author_rank: Regular Contributor
timestamp: May 05, 2017, 12:03:26 pm
content: This is my first post, I am from Malaysia, I purchase faulty test and measurement instruments and repair them for fun.Today I scored a 3458A in an auction, will be getting it soon,Yay.Pictures from the auction shows RAM Test High, the plan is to repair it. After that I will be continuing this post with my full performance verification/adjustment log. I have access to annually calibrated 5720A Calibrator and a 3458A traceable to NIST.

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 05, 2017, 12:33:13 pm
content: Welcome to the boards!!I look forward to your test results. I will be looking to get my first 3458A for my home lab here within the next few months. I'm going to wait for the next decently cheap meter that has got some issues that I can repair.

author: TiN
author_rank: Super Contributor
timestamp: May 05, 2017, 12:40:22 pm
content: QuoteSweet, just wait till somebody breaks it, so we can see what's inside.On serious note, welcome to the club! Be sure to post photos of your 3458A for our enjoyment. Hope your A3 PCBA is good and stable.If you missed my previous experiences,here they are,unit 2,friends unit.

author: theatrus
author_rank: Frequent Contributor
timestamp: May 06, 2017, 06:24:35 am
content: Welcome to the club!What vintage is the unit?

author: usagi
author_rank: Frequent Contributor
timestamp: May 06, 2017, 08:00:15 pm
content: Quote from: CrazyTiger on May 05, 2017, 12:03:26 pmyou won that dovebid auction? i saw it too.i was thinking to bid on it, but the malaysia shipper helen wong @ tucksun would never respond to requests.

author: CrazyTiger
author_rank: Regular Contributor
timestamp: May 07, 2017, 02:47:27 am
content: Yes, dovebid auction for 570 USD. It's a HP era Multimeter but i think it should be a late model. The lot comes with few function generators like HP8904A, HP3325A, here is the link:http://www.go-dove.com/en/auction/view?auctionId=12063720For the Malaysian shipper part, believe me it would be super expensive, in the past they quoted me 400 usd to ship within Malaysia itself, i checked for 400USD I can Fedex it to US. So I will be driving 400km to collect it

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: May 07, 2017, 02:54:45 am
content: That was a great deal on your new gear. The rest of it could help cover the initial/repair costs if needed depending on if you sell anything.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 08, 2017, 11:40:41 pm
content: Excellent score. You should have fun with all of this.
Is the Keithley 2100 the best meter 892 USD can buy ? - Page 1
Forum section: electronics / general

author: ebclr
author_rank: Super Contributor
timestamp: April 22, 2017, 05:53:52 am
content: Apparently, Keithey is more serious than Keisight, after the emf fiasco on hand multimeter, and measurement error according to the zoom on screen in scopes, Keisight is no more old HP quality and reliability they lose the art to make reliable instruments and transformed in beautiful toys instead of a reliable meter.

author: VintageNut
author_rank: Frequent Contributor
timestamp: April 22, 2017, 09:00:34 am
content: You can buy a working Keithley 2015 or 2000 from USD$300 to $400 often from eBay.The 2015 is a 2000 with an added analog AC board that has an ADI SHARC for the digital signal processor.I bought one of each. The 2000 failed and I sent it to Keithley for repair. The cost of replacing the main board was something like USD $568. Replacing the main board results in a brand new DMM for just about everything except the display. The seller refunded my purchase price and told me to keep the dead DMM.The 2015 continues to work well.Both DMMs are very stable for performing entry level volt nutting. The calibration of my repaired 2000 is only off 1pmm at 10V from Keithley's cal lab standard.

author: HighVoltage
author_rank: Super Contributor
timestamp: April 22, 2017, 09:15:01 am
content: If you are looking for a good quality used benchtop DMM, consider the Keysight 34410A. I prefer it any day over the Keithley 2100. You can find them for a round 500$ in perfect condition.And if you want to spend a little more money, get a Keysight 34461A. The screen is not a toy it is really helpful in many aspects.

author: CalMachine
author_rank: Frequent Contributor
timestamp: April 22, 2017, 01:11:27 pm
content: You should check out Keithley 2001's or 2010's.

author: e61_phil
author_rank: Frequent Contributor
timestamp: April 23, 2017, 11:18:01 am
content: Quote from: HighVoltage on April 22, 2017, 09:15:01 amI have a 34461A at work and the 34461A is "only" a new 34401A with a nice display and nice software. If you want something like the 34410A you should buy a 34465A.
Signal Generator in the MHz range - Page 1
Forum section: electronics / general

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 14, 2017, 11:24:14 pm
content: There is a new force in the GALAXY( The is a signal Generator on ebay for 105CAD (~70US) and its rated up to 24MHz and around 14Vpp I think.I just want this as a hobbyist. I have a home soldered kit that does up to about 8kHz wit its capacitors. I look forward to seeing what that chip can do with different timing caps.Here's a review, I plan to get 1.plasma rifle, 40mW class

author: enut11
author_rank: Super Contributor
timestamp: April 15, 2017, 07:23:53 am
content: Excellent demo of this very versatile and inexpensive frequency generator @lordvader88. Perhaps in the wrong section of the Forum?enut11

author: Vgkid
author_rank: Super Contributor
timestamp: April 15, 2017, 07:36:52 am
content: Nice job.Ask a mod to put it in the test gear section. It will noticed there more.

author: NottheDan
author_rank: Frequent Contributor
timestamp: April 15, 2017, 08:14:11 am
content: Have they fixed the mains leakage yet?https://www.eevblog.com/forum/testgear/feeltech-fy3200-psu-upgrade/msg965575/#msg965575

author: chrisalbertson
author_rank: Newbie
timestamp: April 19, 2017, 06:26:24 am
content: I don't think the leak is fixed nor will it be fixed. Also, I think it is a non-problem if you follow common sense procedures like first connecting the generator's signal ground to the DUT's signal ground.I have one of these on order. Got a tracking number. It shipped from a US warehouse so I should have it in the few days.Would you believe, my current RF signal generator is a vacuum tube unit. This will be a step forward in technology.
Available Info/Manuals on Keithley 140-Nanovolt-Amp or ESI 900 Nanovolt-Meter? - Page 1
Forum section: electronics / general

author: Echo88
author_rank: Frequent Contributor
timestamp: April 13, 2017, 10:54:56 pm
content: Hi,both of those instruments are available on ebay and im searching for manuals or infos about them. Maybe someone here has such info?
MJ Research PTC 100 Peltier Effect Cycling - Page 1
Forum section: electronics / general

author: mimmus78
author_rank: Unknown
timestamp: April 12, 2017, 09:25:37 am
content: It seems ebay (US) is full of this thermal cycling equipment once used in biologic labs and now surplus.http://www.ebay.com/itm/262581790370it's programmable and can go for a fair temperature range.It seems it can be easily modified to be used as a basic thermal chamber for metrology purposes after removing the vials plate and replace it with maybe a Hammond aluminium enclosure.Anyone in US that want's to try it?

author: manganin
author_rank: Regular Contributor
timestamp: April 12, 2017, 10:40:04 am
content: Quote from: mimmus78 on April 12, 2017, 09:25:37 amAltering the oven mass will change the optimal controller constants, which may not be user adjustable.

author: mimmus78
author_rank: Unknown
timestamp: April 12, 2017, 10:53:00 am
content: As you can put up to 96 vials of 2ml each one I think it should have some sort of autotune pid algorithm.Than I don't think total mass of the Hammond enclosure will be such different than the vials plate but yes this should be tested.Unfortunately shipping and other customs costs may increase total costs of the experiment to many hundreds EUR and I don't like to spend this amount unless sure.

author: CalMachine
author_rank: Frequent Contributor
timestamp: April 12, 2017, 04:57:49 pm
content: Interesting... I'll look into this!

author: mimmus78
author_rank: Unknown
timestamp: April 12, 2017, 08:52:34 pm
content: Calmachine as far as I understand under the vials bad there is an easy removable assembly with TEC, dissipator and most probably temperature sensor.This thingy is also programmable with multiple programs too.If can be modified, it will be a good deal to get a small thermal chamber for few 100 for our projects.Inviato dal mio Nexus 6P utilizzando Tapatalk
Wavetek 9100 Multifunction - Page 1
Forum section: electronics / general

author: ebclr
author_rank: Super Contributor
timestamp: April 12, 2017, 07:22:33 am
content: Do anybody have schematics, Service manual. Calibration procedure for this calibrator ?

author: manganin
author_rank: Regular Contributor
timestamp: April 12, 2017, 08:25:50 am
content: The three volume user manual set can be downloaded from the Fluke website. See volume 2 for calibration.The 9100 was discontinued in December 2012. The 5 year support period ends this year.It is possible that Fluke releases the service documents after that.
Anyone know zlymex ? - Page 1
Forum section: electronics / general

author: BravoV
author_rank: Super Contributor
timestamp: March 20, 2017, 03:31:34 pm
content: Never read his post anymore here in this forum for quite a while, is he ok ?His account status -> Last Active: 2017-01-04, 09:11:33

author: grifftech
author_rank: Frequent Contributor
timestamp: April 11, 2017, 03:33:01 pm
content: he came back and posted
Antique current shunt for you metrology types - Page 1
Forum section: electronics / general

author: joeqsmith
author_rank: Super Contributor
timestamp: April 14, 2017, 07:32:47 pm
content: A friend of mine gave me this antique General Electric 0.2% 2A/mV 100A shunt. I understand this was in a QC lab from a company that no longer exists. I thought some of you may get a kick out of seeing it.I am not sure what the elements are made from or what appears to be some sort of coating on it.

author: TiN
author_rank: Super Contributor
timestamp: April 15, 2017, 01:38:58 am
content: Doesn't look metrology grade to me.

author: joeqsmith
author_rank: Super Contributor
timestamp: April 15, 2017, 02:09:25 am
content: Appears to be the same shunt as part of a kit. The silver coating must have been original. It appears non-conductive and I would assume some sort of paint for rust. I wonder what the elements would have been made out of.http://www.ebay.com/itm/Vintage-GE-General-Electric-Volt-Millivolt-Shunt-Meter-Kit-In-Oak-Box/122438624828?_trksid=p2047675.c100037.m2107&_trkparms=aid%3D444000%26algo%3DSOI.DEFAULT%26ao%3D1%26asc%3D40130%26meid%3D957f1022499f431ea494ebaf86cc655b%26pid%3D100037%26rk%3D2%26rkt%3D2%26sd%3D122294278726Tried it out for the fun of it.
Fluke Calibration: Philosophy in Practice, second edition, fs - Page 1
Forum section: electronics / general

author: acbern
author_rank: Frequent Contributor
timestamp: June 23, 2016, 03:45:27 pm
content: Should maybe be in the buy/wanted section, but it is so special and also some guys here may really look for this (as I did; it may be easy to get in the US, had a hard time back then when I looked for mine here, so mainly for EU guys (also for shipping costs).:have one that was new in its plastic envelope, NOS, opend it up to just check, but that was it (as I had mine already), so essentially new.Given its condition, thought 60 euro plus shipping would be a fair price. If interested, please send me a PM.

author: mimmus78
author_rank: Unknown
timestamp: April 02, 2017, 04:01:09 pm
content: do you still have it?

author: Alex Nikitin
author_rank: Super Contributor
timestamp: April 02, 2017, 04:23:32 pm
content: Quote from: mimmus78 on April 02, 2017, 04:01:09 pmThere is one available here on the forum.CheersAlex

author: mimmus78
author_rank: Unknown
timestamp: April 02, 2017, 04:27:48 pm
content: Just ordered one used at 26 USD from Amazon.com. I thought they do not ship used books to EU, but it seems there are exceptions.

author: acbern
author_rank: Frequent Contributor
timestamp: April 03, 2017, 06:35:07 am
content: Still available, same price, will not go lower due to new condition (I paid more anyway; list price new is 200+ usd afaik).
INA 125P current to voltage IA - Page 1
Forum section: electronics / general

author: Larezki
author_rank: Newbie
timestamp: March 11, 2017, 11:29:42 pm
content: Hi,Im trying to make a digital ammeter 0 to 1A scale and i have INA125P Instrumentationamplifier, can i use it as current to voltage amplifier with 0.01 ohm shunt resistor ?

author: Larezki
author_rank: Newbie
timestamp: March 12, 2017, 11:54:58 pm
content: sorry i took a look on the datasheet, seems there is everything there thanks anyway guys.
Looking for new multimeter - Test lead quality? - Page 1
Forum section: electronics / general

author: Davy
author_rank: Regular Contributor
timestamp: March 12, 2017, 12:51:05 pm
content: I'm looking for a new multimeter, narrowed my search down to either the Testo 760-3 or Greenlee DM860 that is similar to the Bryman BM869S, still lookin' n' tootin' and reading reviews after reviews, not to watching Dave's excellent tear downs. Thoughts and views are welcome here.We hear about the internal construction of test meters but never about their test leads, many of which the leads 'I feel' would have a job in passing 5 Amps let alone 10 Amps, the wire being diabolically thin and usually connected with a sliver of solder if connected at all.... am I right into thinking all these CAT ratings are related to the leads as well or am I onto something hear?Dave

author: saturation
author_rank: Super Contributor
timestamp: March 12, 2017, 01:26:14 pm
content: Test leads are CAT rated separately, labeled on the leads and separately certified by NRTL type labs.

author: Davy
author_rank: Regular Contributor
timestamp: March 12, 2017, 02:11:20 pm
content: I thought as much, thanks for that saturation, otherwise many would fail I guess.Dave
HP8592A Correction Factors issue etc. - Page 1
Forum section: electronics / general

author: vxh
author_rank: Newbie
timestamp: March 01, 2017, 07:34:48 pm
content: Hi guys,I bought an HP8592A with several problems.I tried to search the service manual and I found all other 85XX versions, nothing about the 8592A.On power on, the grid with annotations come up with no signal or noise line. I made calibration of Freq, Amptd, YTF, stored all but after restart the problem is the same.If I switch Corr to Off, noise floor comes up with a 10db step at 12.8GHz and I can measure Cal Output signal.I suspect the Correction Factors are corrupted and at power on wrong information put the device in that situation.With no service manual for 8592A I tried the procedures for the others HP85XX in order to enter the service menu. The Preset, Frequency, -37Hz (and -2001Hz), Cal do not work. The passcode is not recognized and after pressing the first More softkey there are not more steps.Any idea about a way to solve the problem ?Anyone with a Service Manual available ?
Solartron '7081' Precision Volt Meter  - Page 1
Forum section: electronics / general

author: IconicPCB
author_rank: Super Contributor
timestamp: February 21, 2017, 08:45:14 am
content: http://www.go-dove.com/en/auction/view?id=11862684These are times when one wishes to be in the land of warm beer

author: tggzzz
author_rank: Super Contributor
timestamp: February 21, 2017, 09:15:48 am
content: Tee hee, my picture from last weekOr should that be TEA hee?Looks like the NiCd battery has failed and someone may have fiddled with the calibration.I wonder what the selling price will be.https://www.eevblog.com/forum/chat/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=292630;imageP.S. I was getting worried about my self-control w.r.t. that auction, but then I saw the minimum selling prices

author: IconicPCB
author_rank: Super Contributor
timestamp: February 22, 2017, 07:30:15 pm
content: The unit went for 280 pounds..There was a rush of bids in the final hour of the auction( 5 bids).Damn. I hate warm beer.

author: tggzzz
author_rank: Super Contributor
timestamp: February 22, 2017, 09:18:28 pm
content: I'd better not tell you what I paid for mine 😀 Let me just say that 10.0000V Trancell sources, and some reasonzbly accurate "steam punk" resistors cost me £15 each. OTOH the Weston Standard cells were more or less free.But if I was 20 years younger, I'd be thinking of emigrating to Australia. As it is you don't want to have me

author: IconicPCB
author_rank: Super Contributor
timestamp: February 22, 2017, 09:30:17 pm
content: So it seems great value for 280 pounds.As for me not wanting You... nonsense. I am simply saying... I prefer cold beer.Many years ago I visited a company in the area of Bath. Bath Scientific Limited. I bought one of their flying probe testers.Loved the time I spent there.Other than the architecture and history of the area, the experience of a summer day in a bus travelling past a forest and being flooded by the cool forest air remains with me to date.Australian bush does provide the welcome shade in summer but it is nothing like the cold wave emanating from that forest near Melksham.

author: tggzzz
author_rank: Super Contributor
timestamp: February 22, 2017, 10:35:47 pm
content: Quote from: IconicPCB on February 22, 2017, 09:30:17 pmAgh! I should have written "you lot"! (Unsurprisingly and reasonably you don't want unproductive elderly refugees from Brexit to emigrate and become a burden on the state)QuoteI know Bath well, since it is only 15 miles away.I quite understand your points about forests. I lived in Cambridge for a few years, and while the town was fun, the surrounding country had no contours and no trees. After a while that got to me, since I feel at home walking through forests to emerge on a hillside.My daughter took herself off to Aus between school and university, and greatly enjoyed working her way up the east coast and then down through the centre. She finally ended up with some distant relatives in Melbourne for a couple of weeks. I wish I was young again ;}But, if you have the right mentality, you can find something good/interesting in most places.
mean well EPS-45S - no load power consumption - Page 1
Forum section: electronics / general

author: rozpruwacz
author_rank: Newbie
timestamp: February 26, 2017, 02:41:51 am
content: Hi all,I've just bought a mean well eps-45s-24 power supply. The manufacturer claims that the no load power consumption is <01.W. But when I powered it trough my cheap power meter (http://www.orno.pl//5,energy-meters/62,energy-calculators/t566,1,en,two-tariff-energy-calculator) the meter shows 0.9W consumption. Is this correct way to measure the no load power consumption ? Or maybe the claimed power consumption is not true ?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: February 26, 2017, 03:08:59 am
content: Harry Hu the legendary Hawiian dectective famously says "There are two possibilities".1. 0.9W is less than 01.W. (therefore agrees with spec. )2. 0.9W is greater or equal than 01.W. (if this is the case you could look at the accuracy of your meter )

author: TheSteve
author_rank: Unknown
timestamp: February 26, 2017, 04:32:44 am
content: The specs say less then 0.1 watt no load.

author: bktemp
author_rank: Super Contributor
timestamp: February 27, 2017, 07:15:27 am
content: Everything seems to be within specs: The meter is specified for 1 ~ 3680W, so if you measure <1W, it can show anything.Such an energy meter is useless for measuring standby losses unless it has sub mA current resolution and accuracy at low currents. But most energy meters use a singe current range, rated for >+/-30A, so even a 16bit ADC will only have 1mA resolution.
from Voltnut to Amperenut ... - Page 1
Forum section: electronics / general

author: capt bullshot
author_rank: Super Contributor
timestamp: February 13, 2017, 08:56:45 am
content: Seems like there'll be a new scope for you volt and timenuts ...http://www.sinova-group.physik.uni-mainz.de/files/2016/06/Schumacher-Vortrag-Mainz.pdf

author: TiN
author_rank: Super Contributor
timestamp: February 13, 2017, 12:56:57 pm
content: What is amazing, that new current methods seem to be working at ambient temperatures, according toPDFandPDF.That may mean that in some distant future we can have "DC current reference" from Fluke Calibration.

author: CalMachine
author_rank: Frequent Contributor
timestamp: February 13, 2017, 02:02:48 pm
content: Quote from: TiN on February 13, 2017, 12:56:57 pm🤤

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: February 13, 2017, 02:28:56 pm
content: Adding it to my eBay followed searches now. Maybe in about 20years something will be available.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 13, 2017, 04:16:10 pm
content: It is not just a possible current reference, but also the option to combine with quantum hall effect to make it a voltage reference. Still it is something for low currents, like maybe 0.1 - 1 nA.
How long should you monitor a calibrator output? - Page 1
Forum section: electronics / general

author: Tony_G
author_rank: Super Contributor
timestamp: February 13, 2017, 05:04:53 am
content: Hi All,I've been playing around with IanJ's Excel macro and I'm wondering if there is an industry standard for acceptance testing on a calibrator? My 5440B manual says that the acceptance criteria is, for 1V, 0.999960 to 1.000040 but it doesn't list how long and at what temperature that is.This really isn't my area of expertise so I just don't know if there is a standard - i.e. measure at 24.5C for 24H sort of thing.Any commentary appreciated.TonyG

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 13, 2017, 07:14:39 am
content: Hi TonyG,at first you have to separate specification limits of the instrument, defined for different time scales, versus sample acquisition time, following "Good Metrological Practice" (GMP).Concerning the 5440B specification, you already have several different time scales, like30days, 90 days, and 1year uncertainty, additionally the 10minutes, 24h and 30 days stability specification.Both show different aspects and instability sources of the instrument, and these are defined on fixed temperature ranges, +/-5°C or +/- 1°C from the nominal lab temperature.It's metrological practice, that the lab temperature is usually 23°C, but it may be defined differently in the calibration report.The sources of instability are: Temperature, Ageing, Noise, and EMF, which you may mitigate, or simply include into your uncertainty calculations. The basic uncertainty of the Volt transfer from NIST to your lab has of course to be added; that's also mentioned in the specification.The noise of the instrument plus your comparison instruments (e.g. a 3458A, or an external 10V reference) is the only parameter, which can be influenced or mitigated by different sampling time scales.If you measure the 10V output of the 5440B for 0.1sec time frames, you will see a lot of short term noise. At 1sec ...60sec averaging time, these noise figures will decrease, and the readings will stabilize more and more to consistent values.At longer time scales like > 5minutes, temperature and ageing drifts will already show up and will increase the uncertainty / standard deviation.This whole picture can be summarized within the Allan Deviation statistics, which describes the stability on these different time scales. Maybe you check this idea with the vast thread "stability comparison of DVM", which TiN initiated.. there you will find a lot of such Allan deviation diagrams.To measure the basic uncertainty, it is Good Metrological Practice to average over about 2..4 minutes, and also to determine the standard deviation (2 sigma) over all the samples taken within this time frame.It's evident, that the lab temperature should not change during this measurement, at least not more than the given limits of the instruments used.Frank
Measuring internal temperature of a DMM - Page 1
Forum section: electronics / general

author: enut11
author_rank: Super Contributor
timestamp: February 12, 2017, 01:19:55 am
content: I have an HP3456A and note that it takes a very looong time to stabilise from cold, especially if I want to characterise another device. I think it is related to its internal temperature.I purchased a simple thermometer that reads IN/OUT temperatures and has a probe on a 1m lead. I want to install this probe inside my HP3456A DMM and monitor the temperature rise from DMM cold start and compare the reading to a stable 10v Ref which has been on continuously for weeks.I realise the best way would be to simultaneously log temp and volts but have yet to implement this. In any case it does not affect the validity of my question: Where is the best place in my HP3456A DMM to place the temperature sensor?enut11

author: Vgkid
author_rank: Super Contributor
timestamp: February 12, 2017, 04:07:31 am
content: Your best bet would be to place it on the A20(analog) board. It is the one that is completely covered. I don't remember if it is on the top or bottom of the unit(been about a year since I have opened it up). For placement try the V-Ref board, or around u 200/500 which are the custom hybrid resistor arrays.

author: Andreas
author_rank: Super Contributor
timestamp: February 12, 2017, 08:01:37 am
content: Hello,pay attention that you do not compromize the isolation of the floating part of the DMM.In my K2000 it plays nearly no role where the temperature sensor is placed inside the DMM.https://www.eevblog.com/forum/metrology/project-pimp-a-keithley-2000/msg1106832/#msg1106832So I can place it on the earth referenced side.with best regardsAndreas
3458a GPIB interface failure? - Page 1
Forum section: electronics / general

author: IanJ
author_rank: Unknown
timestamp: February 07, 2017, 08:59:42 am
content: Hi all,On another thread I've been playing with my 3458a and GPIB (82357B clone)....getting on quite well being new to GPIB.Last night I was running a long GPIB logging test but half-way through the 3458a appeared to jump back to local mode......so I reset everything and tried again. Same thing happened.As I played around things got worse, because when plugging in my 82357B the 3458a stays in local mode......but if I leave it and with my PC connected (USB) then after 10mins or so the 3458a will suddenly jump into remote mode (REM & LSTN indicators).I've ruled out a simple connector issue as no amount of wiggling seems to make any difference.The 82357B LEDs do not error, the green ready light stays on......but from what I know I think thats just displaying the USB/PC side of things.I do have another GPIB USB interface, some open source card, but when I plug it in the 3458a does nothing, stays in local mode. I don't have any software/drivers for this card to do much more tests at the moment.I'm assuming that just by plugging in a GPIB inteface the 3458a should immediately jusmp to remote mode (REM LSTN)Worst case scenario maybe the line driver on the 3458a digital board is faulty, I notice on photos there are a couple of interface IC's and what looks to be the main GPIB controller IC........just thinking out loud, maybe I should warm up the soldering iron.?Before I start scoping the GPIB signals.....any hints or tips?Ian.

author: TheSteve
author_rank: Unknown
timestamp: February 07, 2017, 09:39:34 am
content: Just connecting a gpib adapter will not cause it to switch out of local mode.Any chance your 3458a falls into the serial range covered by this service note?https://xdevs.com/doc/HP_Agilent_Keysight/3458A/service/3458A-13A.pdf

author: IanJ
author_rank: Unknown
timestamp: February 07, 2017, 11:27:29 am
content: Quote from: TheSteve on February 07, 2017, 09:39:34 amExcellent.......that's tonights investigation then.Thanks,Ian.

author: IanJ
author_rank: Unknown
timestamp: February 07, 2017, 05:55:35 pm
content: Hi all,Got home from work and straight to it I ran through the service note procedure and it came back my 3458a was ok as far as the grounding problem......although this could be intermittent I guess.So, I hooked up the 82357B and it's working fine, capturing 3458a data as I type.I have left the 3458a with the SRQ indication on, I'm thinking it will let me know the status of the grounding problem if I lose comms again.Ian.

author: dacman
author_rank: Frequent Contributor
timestamp: February 08, 2017, 12:37:38 am
content: Wiggling doesn't always work. I sometimes clean GPIB connections with DeoxIT (sparingly).
Moved to test equipment. Please delete this post! - Page 1
Forum section: electronics / general

author: Wojta
author_rank: Contributor
timestamp: January 30, 2017, 01:46:18 pm
content: Hey all,I was looking for a new multimeter recently. I want something little bit better than the 20$ cheapos Ive been working with. Ive blown my latest one due to overvoltage and I wasnt able to fix it. It had no input protection at all. I want something decent. I was thinking about the uni-t ut139B, it looks to be really good value for money. If anyone could say few words about the 139B or suggest any other meter at the same price tag. Any suggestions will help. Im doing only low voltage stuff, ICs...ThanksBtw: No, I cant afford a Fluke even though I could get 25% of the price as a student.