hybridfree/eevblog-posts huggingface dataset:
Calibrated DMM7510 - Page 1
Forum section: electronics / general

author: kj7e
author_rank: Frequent Contributor
timestamp: May 26, 2018, 11:10:09 pm
content: I was presented an offer I could not refuse and sent my DMM7510 to CalMachine at ENILABS for calibration (and I requested adjustment). He had my 10v reference a few weeks back were it was adjusted to 10.0000017v. My 34465A was calibrated by Keysight in Roseville last Dec, now everything agrees very well. Something very satisfying about this. Now I need more digits ...The Cal Cert was too big to upload, here is a Google Drive link;https://drive.google.com/open?id=13cKhjYruHux91m3_qTZ2RLhpINJhBPT-

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 27, 2018, 02:57:34 am
content: That's an interesting calibration protocol. Thank you for sharing.

author: cellularmitosis
author_rank: Unknown
timestamp: May 27, 2018, 03:15:46 am
content: Nice!Doe this thread also serve as a subtle teaser for that aluminum box wrapped in black foam insulation with heater resistors strapped to it?

author: kj7e
author_rank: Frequent Contributor
timestamp: May 27, 2018, 03:21:34 am
content: Oh yes, that. Work in progress...

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 27, 2018, 03:48:21 am
content: Thank you for sending in your DMM7510! It's always a great feeling when calibrations and measurements, across multiple instruments, agree.

author: AG7CK
author_rank: Regular Contributor
timestamp: May 27, 2018, 04:33:50 am
content: I would like to know what the columns Minimum, Maximum and Uncertainities mean (I guess the last one should read "Uncertainties").I would normally think that Minimum and Maximum are data, but as they are symmetrical about "Nominal" for all rows, they must be calculated values. Calculated how and based on what?The "Uncertainty" of 10 V DC Gain is listed as 0.54 mV () Looking at the specs of 5720A I find (if I am not mistaken) some 4 ppm of value + 3 microvolt or thereabout - i.e. some 43 microvolt. How is the 0.54 mV calculated / estimated and how does it relate to the specs of the calibrator / calibration equipment?

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 27, 2018, 12:03:56 pm
content: Quote from: AG7CK on May 27, 2018, 04:33:50 amIt is a known issue(typo) on our scope of accreditation. With that said... I cannot state a lower measurement uncertainty than what our scope states. The actual uncertainty is significantly lower.
Quantum Electronics Corporation, Precision DC binary voltage source - Page 1
Forum section: electronics / general

author: Haasje93
author_rank: Contributor
timestamp: May 29, 2018, 10:29:03 am
content: Hi everyone!A few years ago, i came across a divice on a Dutch electronics fleemarket. I bought it for a stunning €3.It is a Precision DC binary voltage source, from the manufacturer Quantum electronics corporation manufactured in the USA.It has the serial number of 936, the inside and the outside have the matching numbers.I have done a few times a search on the internet, but i came up empty. Maybe someone here on the forum knows a little bit more?Attached are some pictures of it. As you can see they have used quality parts. I see also some parts of TEL Labs, is that Teledyne perhaps?The batteries that where first in it where heavily oxidated, so i renew the whole battery assembly.I have also done some measurements, but i post them later.I hope someone has some info for me.Kind regards,Christiaan

author: Haasje93
author_rank: Contributor
timestamp: May 29, 2018, 01:05:35 pm
content: Hi!As promised, here are the measurements.Not written in a neat excel font, but on old school paper.I have perform the tests with a 34401A and a Keithley 199. These meters are well known amongst you.The picture shows how the measurements were performed.As you can see on the paper, in the low ranges there is overall a 0.040mV deviation. But if you look at the "0" range, you can see that there was -0.040mV measured.So overall the readings seems right with that, that was selected.Next to the binary ranges, i also measured the last 4 other ranges from the max 10000mV range.Overall i am very satisfied with it.I have compared the two meters, but you'll all know what they say about a man with two watches!I hope that someone perhaps have some schematics for me..Kind regards,Christiaan
won a 3458A on ebay! - Page 1
Forum section: electronics / general

author: niner_007
author_rank: Frequent Contributor
timestamp: May 18, 2018, 08:43:47 am
content: It's in a pretty good condition, it was pulled from a working environment and sold for parts (or so the seller claimed). Self test all OK, will monitor it for a while to see if it's got any stability problems. It has the extended memory option but not 002. It has an HP frame, but it has had some work inside and some Agilent marked parts. The digital board is original.Is there any way to purchase a new chassis to replace the old one, is Keysight selling it?Cheers.

author: ap
author_rank: Frequent Contributor
timestamp: May 18, 2018, 09:05:34 am
content: You can buy a new chassis (metal frame) but it is pretty expensive (500+; dont remember exactly). You can also buy the front panel and rear frame.

author: TiN
author_rank: Super Contributor
timestamp: May 18, 2018, 12:11:40 pm
content: What's wrong with old chassis? Kit is available by P/N 03458-60100 - 700$USD tag.Check if A3 is drifty, because that is $1400 deal there

author: Kleinstein
author_rank: Super Contributor
timestamp: May 18, 2018, 03:36:30 pm
content: With an old unit one may also want to check the input EMI filter (moderate cost for replacement if needed) and the age of the battery buffered RAMs, especially the cal ram.

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 18, 2018, 06:59:03 pm
content: If you have a GPIB adapter and python installed, I can give you my very small script which runs ACAL and reads the CAL factors to verify A3. It writes everything in an excel sheet.I scheduled the script in the windows 7 scheduler. One nice side effect: Both 3458A ran freshly through ACAL when I come to work.Edit: Unfortunately I switched off my measuring computer at work. Therefore, I can't send it before tuesday.

author: niner_007
author_rank: Frequent Contributor
timestamp: May 18, 2018, 09:25:23 pm
content: Quote from: TiN on May 18, 2018, 12:11:40 pmlooks old that's all; yeah, even if I need to do that, it was still worth it

author: niner_007
author_rank: Frequent Contributor
timestamp: May 18, 2018, 09:26:31 pm
content: Quote from: e61_phil on May 18, 2018, 06:59:03 pmI do have both, please do, when able

author: niner_007
author_rank: Frequent Contributor
timestamp: May 20, 2018, 08:29:09 am
content: thank you <3

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 22, 2018, 10:48:49 am
content: Hopefully nobody is disappointed. It's just so simple.I created a cal72.bat which calls python with this script. This batch file was called every morning from the windows scheduler.

author: sokoloff
author_rank: Super Contributor
timestamp: May 22, 2018, 11:11:14 am
content: Quote from: e61_phil on May 22, 2018, 10:48:49 amI love when HP3458A isn't specific enough...Thanks for sharing the script!
Petition to bring back MisterDiodes - Page 1
Forum section: electronics / general

author: zhtoor
author_rank: Frequent Contributor
timestamp: May 19, 2018, 10:38:44 pm
content: This is a petition to bring back MisterDiodes to the forum.best regards.-zia

author: Simon
author_rank: Unknown
timestamp: May 20, 2018, 07:29:35 am
content: Sorry but NO as fair as we try to be this is not a "democracy".
Fluke 8842a original price - Page 1
Forum section: electronics / general

author: tomeo.gonzales
author_rank: Regular Contributor
timestamp: May 10, 2018, 04:24:32 pm
content: Does anybody know the original price of the Fluke 8842a multimeter when it came out about 30 years ago?

author: wn1fju
author_rank: Frequent Contributor
timestamp: May 11, 2018, 03:04:06 pm
content: 1990 catalog has the 8842a for $1045, with IEEE $1205, with AC $1305 and with IEEE and AC $1465. (all in US dollars)
SZA263/LTFLU [Gone] - Page 1
Forum section: electronics / general

author: SvanGool
author_rank: Regular Contributor
timestamp: May 09, 2018, 09:38:00 am
content: There are still 2 left at:https://www.ebay.com/itm/1pcs-SZA263-recision-Reference/112980719086Edit: all 8 gone

author: cellularmitosis
author_rank: Unknown
timestamp: May 09, 2018, 03:46:07 pm
content: 3 on the wayThe SZA263 will hopefully have a future in the cal club

author: zhtoor
author_rank: Frequent Contributor
timestamp: May 09, 2018, 03:52:21 pm
content: Quote from: cellularmitosis on May 09, 2018, 03:46:07 pmit most definitely would have a future if implemented correctly.best regards.-zia

author: eurofox
author_rank: Unknown
timestamp: May 09, 2018, 03:53:50 pm
content: Quote from: cellularmitosis on May 09, 2018, 03:46:07 pmI just ask price for 2 units on the same place where finally order the 2 AD587LQ, they are on the way to my place as well.
Voltage Dividers - Page 1
Forum section: electronics / general

author: GigaJoe
author_rank: Frequent Contributor
timestamp: May 07, 2018, 03:24:28 am
content: Really sometimes need a divider ...Here is Conrad's nice article about:http://conradhoffman.com/HamonResistor.htmlBut what I find-out , if all resistors has the same temp-co, resultant temp-co == 0 . means, in my understanding need to pick close match with temp-co. Then what about resistance, that really not a problem ....using a blade style sharp knife, scalpel, just alter a surface:here my one of the first try , regular resistor altered as 10.0001 K; and hammon divider 1:10 , MELF resistors 5K 25ppm, result: 0.01% output 0.3 ppm temp-codivider with 6 digits precision, 2 resistors in parallel, approx 0.7-0.9 ppm\C - temp-co(i have to have solder and connect everything , then altering resistors)for a long time it not a bad idea, to burn it a 3-4 days, at 150-170 C. became a more stable, need re-coating, ( I warm it up by heat-gun at 140C and drop in conformal coating, repeating a few times.)BTW: seems, only the same # of resistors in the shoulder are self compensating, like 3 Seq. - 3 par; 4seq -4 par; and so on, means divider 1:100 (where # not equal) - would not have good temp-co at all,2 res: 1:53 res: 1:107 res: 1:5010 res: 1:100.001
A man with two clocks... - Page 1
Forum section: electronics / general

author: CJay
author_rank: Super Contributor
timestamp: May 05, 2018, 08:57:15 am
content: Not worth the bother asking because the idiots have taken over.

author: eurofox
author_rank: Unknown
timestamp: May 05, 2018, 09:59:49 am
content: Einstein's theory of special relativity says that time slows down or speeds up depending on how fast you move relative to something else.Approaching the speed of light, a person inside a spaceship would age much slower than his twin at home. Also, under Einstein's theory of general relativity, gravity can bend time.I think you have to look into black holes to find the answer ....

author: zhtoor
author_rank: Frequent Contributor
timestamp: May 05, 2018, 10:11:36 am
content: Quote from: eurofox on May 05, 2018, 09:59:49 aman interesting "treatise" on black holes:-best regards.-zia

author: RoGeorge
author_rank: Super Contributor
timestamp: May 05, 2018, 10:42:16 am
content: Quote from: zhtoor on May 05, 2018, 10:11:36 amThat video is a good example of pseudo-science.

author: GerryBags
author_rank: Frequent Contributor
timestamp: May 05, 2018, 10:50:48 am
content: Quote from: RoGeorge on May 05, 2018, 10:42:16 amNo it isn't. Pseudo-science is treating something as a science without the experimental or observational evidence or a theoretical framework. Saying that there are problems with Relativity, such as dividing by zero to get to an infinite mass or the fact that Schwarzchild black holes are special cases of a single body universe, is not positing an alternative. Crothers is calling Relativity "pseudo-science" so how can his talk be an example of pseudo-science. If you wanted to actually address any of the points he raises, I'm sure everyone would be all ears.

author: RoGeorge
author_rank: Super Contributor
timestamp: May 05, 2018, 11:06:10 am
content: The title itself is a good hint for why that video is not about real science: the words "destroying" and "quackademic" tell enough.Real science is about showing how something works, not about attacking and ridiculing other persons or theories.

author: CJay
author_rank: Super Contributor
timestamp: May 05, 2018, 11:22:49 am
content: Quote from: GerryBags on May 05, 2018, 10:50:48 amNit picking over the definition of pseudo science aside, that guy's talking crap.Please don't degenerate my thread into some new age, pseudo, woo woo bullshit

author: zhtoor
author_rank: Frequent Contributor
timestamp: May 05, 2018, 11:33:09 am
content: Quotemaybe you would listen to Ron Hatch:-(who probably wrote the proverbial book on atomic clocks / gps)https://www.gps.gov/governance/advisory/members/hatch/that isOfficial U.S. government information about the Global Positioning System (GPS) and related topicsbest regards.-zia
Methods of reducing/eliminating the systematic component of error - Page 1
Forum section: electronics / general

author: minhdai2410
author_rank: Newbie
timestamp: May 01, 2018, 03:37:47 am
content: Hello everyone!Tell me please, what methods of reducing / eliminating the systematic component of error of measuring instruments.As I know, some of them - the use of feedback (inverse transformation), exemplary measures (exemplary signals). Can someone already use these methods when measuring any physical quantities or when creating measuring instruments?Thanks you!

author: rhb
author_rank: Super Contributor
timestamp: May 07, 2018, 06:49:50 pm
content: Do you want to correct an analog result or just know what the errors are?For example, voltage references are subject to errors due to temperature, thermal gradients, aging and a long list of other factors. It is my belief, though I should note this is not generally shared by others, that given sufficient historical data and current conditions one can estimate most of the errors quite accurately. That in turn allows for using a digital potentiometer or other devices controlled by an MCU to apply a correction. I shall shortly be testing this using some $3 eBay AD584 voltage references.The first order problem is to be able to accurately estimate the systematic error and predict it if it has a time related component.It might help if you described a specific example.
First volts - Page 1
Forum section: electronics / general

author: MaxFrister
author_rank: Regular Contributor
timestamp: May 03, 2018, 02:43:24 am
content: I’ve been experimenting with voltage references for a while now, slowly descending the rat hole.I began with the basics: ordinary zeners, diodes, diode connected transistors, primitive temperature compensation circuits.I went back in time to look at neon bulbs and a 5651a gas-discharge voltage reference tube (in a HP 400H).From there I experimented with a variety of ICs including TL431, ref5050, and Max6250.More recently I started to experiment with an LM399. Because my goal was to learn something and not to actually have a voltage standard, I designed a simple circuit and had a board made.I just got it working and lashed together enough GPIB cables and software to do some basic logging. The graph shows the first hours of operation. The photo shows the board.

author: zhtoor
author_rank: Frequent Contributor
timestamp: May 03, 2018, 02:47:43 am
content: hello MaxFrister,excellent job. please do record this data for @rhb, he has some interesting ideas for this data.can you post the schematic also?btw. looks like ca. 15uVpp noise in the graph.can you also run a version without the heater turned on.best regards.-zia
Keysight Benchview question. - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: May 05, 2018, 09:35:02 pm
content: The advanced members here are mentioning week-long measurement runs. Can this be done with Benchview?The DMM I bought can have IEEE option but didnd't think I would need it. Benchview and USB are on it though. Regular panel controls seem to be limited to one hour histograms max. It's a 34470A.I've learned a lot on the Metrology board in the last several months.George Dowell

author: kj7e
author_rank: Frequent Contributor
timestamp: May 05, 2018, 10:56:21 pm
content: You dont NEED Benchview or GPIB for your 34470A, you can capture and log data over the LAN or USB from a Windows, MAC or Linux computer. With Windows, I'm using the Keysight I/O suite which has the Keysight VISA library. There are a few methods to doing this, but I'm using PyVisa and Python scripts.Here is a video series which got me started;https://youtu.be/BP12Qa1yt0wI'm no expert here but I have this working with a few of my instruments now. Only took me a few days to get something up and running.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 06, 2018, 11:22:38 am
content: If you buy the new DMM app for BenchVue, you can used it for unlimited logging.If you download the older version of BenchVue (v3.7) you can have logging for up to 1 hOr, if you use the very old (pre BenchVue) and free Agilent DMM logging software, you can do unlimited logging as well.

author: MaxFrister
author_rank: Regular Contributor
timestamp: May 06, 2018, 02:11:16 pm
content: I recently went through the exercise of setting up logging for my lab. I tried a number of things including “Benchvue” . In the end I did not end up using it for a number of reasons:It is expensiveI had driver problems (because I also had NI GPIB drivers on that machine).It is buggy. For example if I zoomed into a live graph, it would stop automatically updating the graph.It was limited. For example, it could not turn off the VFD display of my 34401a for long logging without display wear.It could not be combined with other instruments. For example, I could not simultaneously log temperature.

author: kj7e
author_rank: Frequent Contributor
timestamp: May 06, 2018, 02:42:10 pm
content: I almost forgot, have a look at 0xfede's Keysight DMM Plot software which connects over the LAN;https://www.eevblog.com/forum/testgear/keysight_s-new-34465a-(6-5-digit)-and-34470a-(7-5-digit)-bench-multimeters/msg1356944/#msg1356944It will only plot whats in the meters memory, but the meter will store many hours worth even without the MEM upgrade. In the trend chart display menu, you can select time from 1 min, 5min, 10 min, 30 min or 1 hour, but there is also another button that will show ALL.

author: kj7e
author_rank: Frequent Contributor
timestamp: May 08, 2018, 03:09:47 am
content: You may also want to look at this new OpenSource EEZ Studio;https://www.eevblog.com/forum/testgear/eez-studio-for-accessing-your-(scpi)-instruments/msg1509535/#msg1509535Looks fantastic and works with the Keysight SCIP commands. Its on my list to play with it this week.
Migrate from the 34401A/34410A/11A to the Truevolt DMMs - Page 1
Forum section: electronics / general

author: CaTx
author_rank: Newbie
timestamp: May 03, 2018, 01:24:00 am
content: I was reading around on the differences between the legendary HP 34401A and newer models. There are two articles:Migrate from the 34401A to the New 34461A Truevolt Digital Multimeter (DMM)Migrate from the 34410A/11A to the Truevolt Series Digital Multimeters (DMMs)Tired of flipping back and forth to see the Comparison of Key Features tables, I decide to merge them and post it here for the community:
Off-Label LM399 - Page 1
Forum section: electronics / general

author: zhtoor
author_rank: Frequent Contributor
timestamp: April 29, 2018, 12:27:33 pm
content: -

author: rhb
author_rank: Super Contributor
timestamp: April 29, 2018, 04:36:24 pm
content: The noise of the LM399 is 25% lower at 25 C according the the National datasheet. How much would cooling it with a Peltier device help the noise?

author: rhb
author_rank: Super Contributor
timestamp: April 29, 2018, 06:21:32 pm
content: 0 and -10 C would be more useful as those should be possible with a Peltier cooler.TiN has a long run of liquid nitrogen data, but I don't think he has had time to write up the experiment. I'm very much looking forward to studying it once he has time to describe the procedures and equipment.
First Light: AD2702SD +/-10V Precision Reference - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 28, 2018, 06:56:03 pm
content: This is a test of old but never used AD2702SD Mil-spec version with bipolar output and metal case.Conditions:+/- 15.0 DCV from bench power supplyFirst power on-+Port = 10.000345-Port= -9.9991 on calibrated Keysight 34470AThere are provided trimmer ports for both + and - outputs with +/- 30mV swing. This has not been implemented on this test jig yet. When it is, it will be switchable so further temp testing can be done with and without it in. There is a derating factor if it is in. However I have not started work on chamber yet.raw pics at:http://www.qsl.net/k/k0ff/VOLT_NUTS/AD2702SD/"1-Dot" label refers to a tiny red paint dot marked on the top, so I can tell it apart from the second one in lie for testingGeorge Dowell
Nucleonics - Measuring eV (electron Volts) - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 24, 2018, 09:13:13 am
content: Measuring Volts is pretty easy.Turns out measuring electronVolts isn't really out of reach of the home lab either.Basically an eV is the amount of energy gained when a single electron is accelerated through an electric field of one Volt. It is applied to other things than electrons though, it's just easier to say eV than 1.6 X 10^-19 J (Joule).Once the technique is mastered, the readings can be applied to many different fields of study, such as determining the age of some rock formations or the age of radioacive fallout.My machine is capable of measuring from around 5 eV to around 3 million eV (3 MeV) or higher.George Dowell

author: Vgkid
author_rank: Super Contributor
timestamp: April 24, 2018, 05:21:56 pm
content: That was a rather interesting read. I will read your other documents later.
First Light: IET HSVR + KVD = 05.000000V @ 18.5 Degrees C - Page 1
Forum section: electronics / general

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 22, 2018, 02:19:36 am
content: With a temp. rating 0-50 C, 1ppm/C22V input from regulated bench supply to an IET High Stability Voltage Reference module, or HSVR-6.3, specified at 6.2998V (ref. NIST). At first power-on it read 6.299995V then started settling down.1.000000V and 5.000000V via a 10k Ohm Kelvin Varley Divider.Measurements made with factory calibrated Keysight 34770A, auto-caled @ 18.5 C (stable) and set to 1G input.HSVR has been sitting in its original packing and box for over a decade, never powered up until today.George Dowell (Geo)PICTURES LINK:http://www.qsl.net/k/k0ff/VOLT_NUTS/IET_HSVR_6.3-FIRST%20_LIGHT/

author: Vgkid
author_rank: Super Contributor
timestamp: April 22, 2018, 03:19:28 am
content: So you bought it , I was eyeing it on epay.Will we see a teardown?

author: zhtoor
author_rank: Frequent Contributor
timestamp: April 22, 2018, 05:51:23 am
content: you need VOLTAMYCINwelcome to volt-nut-land.best regards.-zia

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 22, 2018, 07:22:36 pm
content: "So you bought it , I was eyeing it on epay.Will we see a teardown?"Referring to the regulator?No teardown but I did x-Ray it, not what I expected inside.George Dowell

author: zhtoor
author_rank: Frequent Contributor
timestamp: April 22, 2018, 07:27:08 pm
content: Quote from: GEOelectronics on April 22, 2018, 07:22:36 pmcan you share the x-ray images?best regards.-zia

author: HighVoltage
author_rank: Super Contributor
timestamp: April 22, 2018, 07:58:03 pm
content: I watched this one on ebay as well.Yes, it would be nice to see some xray picturesHere is the datasheet from the IET website.

author: zhtoor
author_rank: Frequent Contributor
timestamp: April 22, 2018, 09:45:14 pm
content: Hello George,i am interested in how this unit is put together,any schematics available by any chance? any date codes? year of manufacture?best regards.-zia

author: GEOelectronics
author_rank: Regular Contributor
timestamp: April 23, 2018, 12:48:56 am
content: Hi Zia. No schematic, we'll be lucky to get them to tell about which technology is in there.Yes I have all the other information and will be happy to share it with you privately but not for publication online.Along with the normal documents came a certificate good for 15% off the first recalibration at IET.With luck, next weekend we will have an AD2702SD to try. Both these devices squeeze good performance out of a non-oven protected reference and I wanted to investigate that type technology first.George Dowell
DataChron 2000 Network Time Server - any info? - Page 1
Forum section: electronics / general

author: Ash
author_rank: Regular Contributor
timestamp: April 22, 2018, 01:12:33 pm
content: Hi Everyone,Help. I'm in danger of becoming an amateur time-nut as well as an amateur volt-nutToday, I was gifted a Datachron 2000 network time server. So far I've only found a 2 page datasheet on it. It appears that the company is long gone.Does anyone know much about this? Anyone have a manual? Nothing is coming up for me in the usual places..It is essentially a GPSDO OXCO with reference outputs (10 of 1MHz, 10 of 10MHz) plus IRIG B. It also performs as a NTP time server over ethernet.I cleaned it up and fired it up this evening. It managed to acquire GPS lock and time. I was also able to do some basic network connectivity, but I've not run up NTP to it yet.I've attached some photos of the internals! Enjoy.Ash.
Another rusty burnt gear repair project. - Page 1
Forum section: electronics / general

author: TiN
author_rank: Super Contributor
timestamp: April 19, 2018, 09:35:20 pm
content: Very kind friend helped me to part with some $$ for another volt-nut toy. The smoke definitely escaped on this one.Who know what this piece is?Will I get it fixed?

author: schmitt trigger
author_rank: Super Contributor
timestamp: April 19, 2018, 09:46:47 pm
content: Very likely C669 (the burnt part) is identical to C668 which seems intact.Its either a MOV or an XY capacitor. Likely the later, because the "C" designator.Close up photos of both sides of C668 could provide clues.

author: MadTux
author_rank: Frequent Contributor
timestamp: April 19, 2018, 10:08:42 pm
content: Looks Keithleyish, not sure about the exact model, thoughMaybe K2182, there are new pics on xDevs.com and you once noted you'd have/get something better than K182?

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 19, 2018, 10:20:15 pm
content: 2182

author: TiN
author_rank: Super Contributor
timestamp: April 20, 2018, 07:20:43 am
content: Not just any 2182

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 20, 2018, 01:47:15 pm
content: seems like someone applied too many nanovolts to the input
Want to Run Your Own Calibration Business? - Page 1
Forum section: electronics / general

author: DeanCording
author_rank: Contributor
timestamp: April 18, 2018, 01:10:12 am
content: There's one up for sale at the moment for a cool $9mil.https://absbusinesssales.com.au/business-detail/business-for-sale-brisbane,1925"annual turnover inclines every year with a 30%+ profit margin"(I have no association with ABS or the business in question - just posted as an example of what these sort of enterprises cost)

author: mimmus78
author_rank: Unknown
timestamp: April 18, 2018, 08:10:42 pm
content: Starting worrying about someone here get broke ...Inviato dal mio ONEPLUS A5010 utilizzando Tapatalk
A first order voltage reference measurement approximation - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: April 15, 2018, 01:34:48 am
content: After reading various descriptions of the 3458A I think it wise to skip over the multislope operation for the initial model. My current model candidate is as follows:1) Generate the noise component limited to one 1/f noise source and one thermal noise sourcecompute Vnoise = Gaussian(Tmean, Tsigma) + A*Poisson/f in the frequency domain from DC to 3 KHz to create a one hour record usingfour independent Mersenne Twister PRNG sequences for the 1/f and thermal noise, one for the real part and one for the imaginary part.The frequency sampling is 278 uHz.2) inverse transform to time and add Vdc and mains noise3) integrate for PLC=10 and subsample to 6 Samples/SThis basically assumes a "perfect" 3458A. So all the noise is attributed to the reference which is assumed to have no drift over the course of one hour.The Nyquist is 3 Hz, but the first notch is at 6 Hz, so everything above 3 Hz is aliased. This seems to me the easiest way to reproduce the effect of the integration in the 3458A.The experiment is to see how much data I need to recover Vdc to < 1 ppm if I account for the noise explicitly in an L1 inverse problem. This is not a sparse L1 pursuit, that implies multiple models for the 1/f noise and trying to find the one that fits best. Or more than one noise source with different characteristics. It's the first step towards doing that and it seems that no one has done this. based on what I found searching IEEE Explore.What I have in mind doing was not practical when the 3458A was designed. I was in grad school in Austin at the time. We could barely do L2 problems of this size on an 11/780. I don't even want to think about how long a 22 million sample FFT would have taken. Probably a couple of days. Now it's a trivial problem.

author: zhtoor
author_rank: Frequent Contributor
timestamp: April 15, 2018, 12:11:26 pm
content: Quote from: rhb on April 15, 2018, 01:34:48 amhello,or use this:-http://ubld.it/products/truerngprobest regards.-zia

author: rhb
author_rank: Super Contributor
timestamp: April 15, 2018, 01:12:38 pm
content: I'd like to kill this thread. I've copied the initial post to the sparse L1 pursuits thread which is where I should have put it in the first place.In this instance, a high quality PRNG is preferable to a true RNG.
HP 3458A (and other) DMM ADC and analog front end details - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: April 14, 2018, 05:04:50 pm
content: I'm about to write a program to model a voltage reference with 1/f and thermal noise. I need to account for the anti-alias filter. At 8.5 digits, the requirements are rather daunting and will need to be handled properly.Can someone point me to where I can find a detailed description of the input design of any of the high end DMMs? I've downloaded all the application notes and manuals from the 3458A page, but I noticed is was "assembly level" service.I'll try the 3456A documentation later.

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 14, 2018, 05:26:42 pm
content: For the 3458A, the schematics are available, 'CLIP', but no Theory Of Operation.A good analysis of the front ends of 34401A and 34420A are in the latest issue of The Art Of Electronics.Frank

author: alm
author_rank: Super Contributor
timestamp: April 14, 2018, 06:00:35 pm
content: In addition to the service manuals, you may also find some "theory of operation" level information in HP Journal issues about the meter:3458A:April, 1989 issue (PDF link)3457A:February, 1986 issue (PDF link)3456A:April, 1981 issue (PDF link)3455A:February, 1977 issue (PDF link)Not sure if any of them cover the front-end to the level of detail you desire.

author: rhb
author_rank: Super Contributor
timestamp: April 14, 2018, 08:23:32 pm
content: The HPJ discussion about the 3458A ADC is great, but I so wish it were not in blue ink. Many thanks. I'll probably download the entire archive.
Pretty nifty part - 200mA voltage reference - Page 1
Forum section: electronics / general

author: daqq
author_rank: Super Contributor
timestamp: April 11, 2018, 07:16:51 am
content: This is nice:http://www.analog.com/en/analog-dialogue/articles/the-refulator-the-capabilities-of-a-200-ma-precision-voltage-reference.html?7380&ADICID=EMAL_WW_P1274_SUB-NL-PN_290&elqTrackId=fd74a4d584c1403ba6abc94af05926d7&elq=e0096cfe1ec8410a998a95b619d04450&elqaid=7380&elqat=1&elqCampaignId=4102Pretty much a precision linear voltage regulator.

author: tszaboo
author_rank: Super Contributor
timestamp: April 11, 2018, 07:33:36 am
content: I love, how Linear technology casually drops in some parts in their application notes. Like Figure 12. Let's just throw in some resistors next to our 10ppm/K reference voltage to multiply the signal, no problems right? Let's just ignore the tempco of resistors, the effects of real world components. Let's just not mention that we used film capacitors to filter the reference, or that you need passives that cost more than the IC to not completely ruin the performance.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 11, 2018, 03:04:55 pm
content: Nice to have another unique alternative...

author: PartialDischarge
author_rank: Super Contributor
timestamp: April 11, 2018, 04:38:02 pm
content: I wonder what program they use for those circuit schematic graphics....

author: kosine
author_rank: Regular Contributor
timestamp: April 11, 2018, 05:05:12 pm
content: Interesting part. Digikey has the B-grade version for around £4 (20ppm/C and 0.1% accuracy); The A-grade is a little more expensive but offers the 10ppm/C and 0.05% spec.However, it only seems to be available in 2.5V output and a 16 pin SOP package. So not very breadboard friendly for prototyping, and not ideal if you need a different voltage. (As pointed out above.)I guess the substantial output current is a key feature here, since you can run a whole circuit from it.If that's what you're after, then an nice cheaper alternative is the 3-pin LP2950. About £0.60 each, and the specs are not too far behind. 100mA output at 20ppm/C and 0.5% accuracy. (In practice I've found them to be generally better than that, maybe around 0.25%.)They're available in 3V, 3.3V and 5V outputs, which makes them quite suitable for half-decent ADC measurements on casual microcontroller projects.The designers also made the pin out the same as the venerable 78L05 (which are +/-5% output at best), so it's a good affordable component for upgrades and a nice easy step for beginners to get into more precision circuits. Well worth adding a few to your parts bin.

author: daqq
author_rank: Super Contributor
timestamp: April 11, 2018, 05:23:14 pm
content: QuoteActually, the output is seems adjustable by using the SENSE pin as a resistive feedback.
coming soon?  mini Cs vapor cell clocks - Page 1
Forum section: electronics / general

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 09, 2018, 04:22:37 pm
content: http://teams.femto-st.fr/equipe-ohms/cs-vapor-cell-atomic-clocks

author: edpalmer42
author_rank: Super Contributor
timestamp: April 09, 2018, 04:59:47 pm
content: Isn't this the same as:https://www.microsemi.com/product-directory/clocks-frequency-references/3824-chip-scale-atomic-clock-csacwhich has been commercially available for some years?Ed

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 09, 2018, 08:15:15 pm
content: Appears similar. Hopefully it is a price thing. $5300 for Microsemi's device is a bit steep...https://www.mouser.com/ProductDetail/Microsemi/090-02984-001?qs=sGAEpiMZZMvo8iywG0hSDQnxQwf0%252bKLL8OM7FiQJWwU%3dand the eval board is $1000

author: edpalmer42
author_rank: Super Contributor
timestamp: April 09, 2018, 08:22:24 pm
content: Keep in mind that although these are Cesium devices, they aren't what you normally think of when you hear 'Cesium Standard'. Their performance is similar to a Rubidium Standard. i.e. they drift - slowly, but they do drift.Ed

author: Vgkid
author_rank: Super Contributor
timestamp: April 09, 2018, 08:54:54 pm
content: From what I remember reading a while ago these csacs are closer to the average rb oscillation in design , than a cesium clock. They used cesium instead of rubidium.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 11, 2018, 03:06:27 pm
content: Darn... I wanted a fountain on my wrist
[solved] Pt100 measurement by 3458A - Page 1
Forum section: electronics / general

author: dl1640
author_rank: Regular Contributor
timestamp: April 11, 2018, 08:57:50 am
content: Hi,I noticed that 3458A can do MATH CRTD85 to directly display the temperature measured by a Pt100, with 4w Ohm function, however it is in itps-68, what if I want it to calculate as its-90? No way?

author: voltsandjolts
author_rank: Unknown
timestamp: April 11, 2018, 09:53:42 am
content: Readout in Ohms and calculate temperature as per your requirements

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 11, 2018, 10:38:12 am
content: Probably you're right, as the firmware was initially written before SI-1990 / itps-90, and there were no adaptions mentioned in the ANs.Your only chance is either to use correction factors for certain temperature ranges as secondary math function, e.g. factor 0.99976 for -2°C ... 40°C, set SCALE = 1.00024 , or you have to write a BASIC program for the 3458A which would replace the built-in PT-100 conversion.FrankPS: By next year, 20th May 2019, the temperature scale will also change again, besides kg, and other definitions.

author: dl1640
author_rank: Regular Contributor
timestamp: April 11, 2018, 12:41:25 pm
content: thank you Frank, it looks impossible to read out against its-90, 3458A is 1989 monster.
ADS1115 - Page 1
Forum section: electronics / general

author: JS
author_rank: Frequent Contributor
timestamp: April 23, 2018, 06:54:24 am
content: I do know you voltnuts are going to shoot me hard on this!After a few days fighting to get working an STM environment I decided to have some fun. Just testing an ADS1115 (16b ADC, with internal reference, MUX and diferential PGA) as it seemed a nice toy, Arduino nano, adafruit example, see what it throws. Out of the box, no calibration, 50mV test gives results within 0.5% of the BM235!!!Ok, let's take out the noise, some averaging... 0.1% WTF!!!Of course, take it as it is, single sample with single 3.5 digits DMM. I'm not saying this will be my volt reference, but I guess there is quite some value in it! Could be useful for some projects.JS
recent DMMCheckPlus orders hitting the streets - Page 1
Forum section: electronics / general

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: March 24, 2018, 08:40:53 pm
content: Doug Malone has started shipping new DMMCheckPlus units out (ordered a while ago, of course).Just got mine. Fun!http://www.voltagestandard.com/P.S. Apologies for getting the photos the wrong way around!

author: jasonbrent
author_rank: Regular Contributor
timestamp: March 25, 2018, 04:37:36 am
content: I received mine yesterday and spent a little time with it and my 2015. Everything seemed in spec, thankfully.
Calibration club standard inductor and capacitor? - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: March 22, 2018, 02:25:50 pm
content: I have a rather large pile of WWII antenna tuning units. These were built of the finest materials of the day. Steatite insulators and silver plated wire and switches. I'd guess they are rated to several hundred volts and watts.Would it be useful to have some traveling references? What I have in mind is mounting them in an enclosure and pulling a fairly hard (e.g. a few microns) vacuum. Then installing that in a larger enclosure with insulation and a temperature control circuit. The outer enclosures would be made from the tuning unit front panel and the case. They're roughly standard rack size, but I've never measured on. It's all aluminum, so lightweight.I don't propose to trim them to value. Rather the idea is to have a number of precisely measured values made from very stable materials. Have a USB interface that would allow reading temperature and frequency correction factors and verifying vacuum integrity.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: March 22, 2018, 03:42:26 pm
content: As the box gets larger, shipping costs get out of hand. There were various things I wanted to include last time, but couldn't. Maybe better to have some standards without stabilization and just record temperature and establish a calibration curve?

author: TiN
author_rank: Super Contributor
timestamp: March 22, 2018, 04:48:04 pm
content: I had some data samples received recently from capacitance bridge, which I'd like to keep unnamed for time being, with two standard capacitors as DUT: 10 and 1000 paff.Test frequency : 1000 Hz.I'm impressed with resolution. Vertical scale on the most left - ppm of the reading.

author: cellularmitosis
author_rank: Unknown
timestamp: March 22, 2018, 05:29:54 pm
content: 13 oz. is the magic number for being able to use US Postal Service First Class Package service, which is usually the cheapest shipping option. Beyond that it becomes a hunt between UPS, Fedex and the flat-rate Priority Mail options from USPS.One approach you could take is to attempt to keep a few heavier, ultra-stable known-good references at home, and then ship around a lighter transfer standard, which can be calibrated / adjusted to your known-good references at home after each leg of the trip. This is what I'm going to attempt to do with resistance standards, anyway (oil-immersed at home, copper-wire tempco resistor compensated for the traveling references).

author: rhb
author_rank: Super Contributor
timestamp: March 25, 2018, 01:03:30 am
content: @TiN I see that the key shows environmental data which are not plotted. Can you post the temperature, humidity and pressure data?

author: TiN
author_rank: Super Contributor
timestamp: March 25, 2018, 04:14:14 am
content: Not at the moment, that data was not logged for these initial measurements, sorry.
Elektrostatic Voltmeter 30kV - Page 1
Forum section: electronics / general

author: Physikfan
author_rank: Regular Contributor
timestamp: March 17, 2018, 08:00:55 pm
content: The picture shows an electrostatic voltmeter with light mark pointer for a maximum of 30 kV.In contrast to the other 10 kV electrometer, this instrument has two additional measuring ranges 7.5 kV and 15 kV:
Guildline 9975 resistance bridge - Page 1
Forum section: electronics / general

author: scottbp
author_rank: Newbie
timestamp: March 14, 2018, 05:05:59 pm
content: I have a Guildline 9975 resistance bridge that I'd like to resurrect. Does anyone know where I can find an operator or service manual? I did a search of this forum and found a link to a teardown athttp://bbs.38hot.net/thread-4488-1-1.html,but it's in Chinese. Nice pics, though, at least I don't have to open mine up just yet.

author: Vgkid
author_rank: Super Contributor
timestamp: March 14, 2018, 05:17:25 pm
content: I seem to recall that Measurements International used to service these , after guildline.

author: chuckb
author_rank: Frequent Contributor
timestamp: March 14, 2018, 05:33:20 pm
content: Quote from: scottbp on March 14, 2018, 05:05:59 pmIf you view the bbs.38hot site with CHROME the Google Translate function will let you read everything very well.There are many good articles on the 38hot site.

author: ap
author_rank: Frequent Contributor
timestamp: March 14, 2018, 08:14:55 pm
content: I have one running in the lab, used mainly for 1/10 transfers. Send me a PM re. the information you need if you like.Maybe we can also exchange operational experience later on.

author: cellularmitosis
author_rank: Unknown
timestamp: March 15, 2018, 07:59:32 am
content: Unfortunately the forum picked up the comma in your URL, which makes it 404. Here’s the link without the commahttp://bbs.38hot.net/thread-4488-1-1.html

author: scottbp
author_rank: Newbie
timestamp: March 15, 2018, 02:36:39 pm
content: Oops on the comma... Thanks for the tip on using Chrome with Google translator. Response from one of the posters on that site: "Never knew that there is so much knowledge of a resistor."

author: lowimpedance
author_rank: Super Contributor
timestamp: March 15, 2018, 10:17:47 pm
content: There were some variations in the manuals (have several at work), best to see what information you require then place a request here .

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: March 16, 2018, 11:31:43 pm
content: Email Guildline and request a copy of the manual.They will happily send you a pdf copy and remind you they no longer service it. They will also provide a hardcopy in the $300 range.The one they send is TM9975-J-00/

author: dl1640
author_rank: Regular Contributor
timestamp: March 16, 2018, 11:40:54 pm
content: Lucky that I can read 38hot in Chinese, the uploader username "lymex" has many study and research on precision instruments and standards I think. But this man is not active on 38hot and eevblog forum for a while..

author: quarks
author_rank: Frequent Contributor
timestamp: March 17, 2018, 10:57:59 am
content: I had some private conversation with lymex, but he is not responding anymore, so I hope he is wellit would be great to here from anyone if he is ok

author: 0.01C
author_rank: Regular Contributor
timestamp: March 17, 2018, 05:18:53 pm
content: Quote from: quarks on March 17, 2018, 10:57:59 amI just talk to him yesterday ,He said he was busy and didn't have time to go online.
In memoriam: Ron Swerlein - Page 1
Forum section: electronics / general

author: martinr33
author_rank: Frequent Contributor
timestamp: March 17, 2018, 05:02:06 am
content: Ron Swerlein was one of the deisgners behind the HP 3458a, which we all know is a remarkable piece of engineering. I know little of him, other than that he was a pillar of the design of the 3458a, and had a genuine passion for chemistry (which I appreciate).http://www.howemortuary.com/obituaries/Ronald-Swerlein/#!/ObituaryHe deserves a memorial in this forum. Many of us enjoy examples of his work.

author: zhtoor
author_rank: Frequent Contributor
timestamp: March 17, 2018, 05:08:44 am
content: I second that motion !-zia
Fluke 5440B - 1000V range broken - Page 1
Forum section: electronics / general

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 08, 2018, 09:46:25 am
content: Hi,the 5440B from "a friend" has a problem. It is unstable in the 1000V range.If I select 275V it is rock stable (measured with HP 3458A). If I go to 276V (next range) the voltage begins to change in the range of a volt. If one goes higher in voltage (~700V) the 5440B sounds like an overloaded switching power supply and resets a couple of seconds later.The HV selftest stops with „FIL B/OUT BRDS FAULT CHECK +1100V RANGE“. I doubt that this is the problem, because 275V are stable.Does anyone know such behaviour?ThanksPhilipp

author: TiN
author_rank: Super Contributor
timestamp: March 08, 2018, 11:45:40 am
content: QuoteMaybe Fluke knows better?I'm not familiar with 5440B, but in 57x0A PA in 220V range using another set supply rails (+/-250V) instead of high voltage, to limit the thermal dissipation. After all these calibrators are linear devices, so heat is an issue. If 5440 use same idea, than kV range would be powered from other rails than lower range.

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 08, 2018, 02:42:55 pm
content: In the 5440B there is only a +/-30V and all the rest comes from the controlled HV transformer.

author: TiN
author_rank: Super Contributor
timestamp: March 08, 2018, 05:02:23 pm
content: Ok, my bad then. Check if high voltage generated properly.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: March 08, 2018, 09:44:40 pm
content: Quote from: e61_phil on March 08, 2018, 02:42:55 pmAnd there's the crux. The +/- HV rails are controlled by a bunch of triacs to suit different ranges of output voltage. Guess which part of the control circuitry is malfunctioning in your friend's 5440?The service manual has all the info needed.