hybridfree/eevblog-posts huggingface dataset:
SMT reference resistors: make sense? - Page 1
Forum section: electronics / general

author: technix
author_rank: Super Contributor
timestamp: December 03, 2018, 03:36:17 pm
content: LCSC is running a promotion here on the Chinese version, and one of the brands offer this resistor: 10kOhm, 0.1%, 25ppm drift, in 1206 package.Is that a good reference resistor? How should I design the adapter board for it?

author: TiN
author_rank: Super Contributor
timestamp: December 03, 2018, 05:47:02 pm
content: Does not sound like anything reference to me.

author: technix
author_rank: Super Contributor
timestamp: December 03, 2018, 07:39:30 pm
content: Quote from: TiN on December 03, 2018, 05:47:02 pmSo far that is my best resistor... I know that this isn't that great as reference...
Limits of the GPS DSO - Page 1
Forum section: electronics / general

author: jfphp
author_rank: Regular Contributor
timestamp: November 26, 2018, 03:04:36 pm
content: People always consider that the GPS DSO is the ultimate reference avoiding at least a cesium clok. You must be aware of the limits of the system. For example attached a comparison between a HP 58503B and a 5061B clock (10 min per division). Long time averaging is mandatory and limits the eye's comparison at a glance for the offset and drift of an high quality oscillator.

author: tkamiya
author_rank: Super Contributor
timestamp: November 26, 2018, 04:15:59 pm
content: I think people are aware of this limitation. I am.... I think of GPSDO as an ultimate timebase I can actually afford. For practical purpose though, this is as good as I would ever need.
EDC CR-10NR Voltage and Current Standard  Any info/schematics? - Page 1
Forum section: electronics / general

author: BC7333
author_rank: Newbie
timestamp: November 22, 2018, 11:27:28 pm
content: Hi all,Anyone have schematics or manual for this standard? There is also what looks like an empty nixie tube socket on one of the boards, see picture. Calibration port maybe?Volts and mA output okThanks!

author: Magnificent Bastard
author_rank: Regular Contributor
timestamp: November 23, 2018, 12:51:30 am
content: If you send EDC the picture you have there and a small picture of the serial number-- and ask them for a PDF manual-- they will often just send it to you. These will include schematics.

author: BC7333
author_rank: Newbie
timestamp: November 23, 2018, 07:51:43 pm
content: Sent a request to Krohn-Hite back in May but no answer :/Sent a reminder today.
Fleabay item: Julie Research 7-decade Kelvin Varley Divider - Page 1
Forum section: electronics / general

author: tggzzz
author_rank: Super Contributor
timestamp: November 27, 2018, 02:58:01 pm
content: If anyone wants one, there's a 7 decade Julie Research Kelvin Varley Divider up for sale:https://www.ebay.com/itm/Julies-Research-Lab-Vintage-Rare-JRL-VDR-106-7-Voltage-Divided-NICE-Mod-A/302961144684I've no affiliation to the vendor.I own one of these, like it (apart from the size/weight!) and am not going to part with it, but would like to establish a track record for the price of them

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 27, 2018, 06:30:58 pm
content: I've got a 6-decade Julie I bought directly from them when they were still in business. It was the prototype and is serial #1. It was a few hundred $, if I remember right. I've got another one picked up at a hamfest or somewhere for far less. Mine are both the lesser versions with individual resistors and short lengths of manganin to trim them. Also have an ESI version of the same thing. The big units like the one shown I believe use the oil can resistor banks. Somewhat better performance, but probably near impossible to service if anything goes wrong. The insane price of new ones seems to be causing the price of the old ones to rise. OTOH, they're rarely used anymore, which keeps a bit of a lid on the price.

author: tggzzz
author_rank: Super Contributor
timestamp: November 27, 2018, 06:57:38 pm
content: Quote from: Conrad Hoffman on November 27, 2018, 06:30:58 pmYes, for the more significant decades. That's one reason for the weight.QuoteAgreed, but you would have to try fairly hard to damage them. Couriers could manage to damage them, no doubt.QuoteAgreed. That price would not have been acceptable to me, since for me it is merely a diverting hobby.

author: 1audio
author_rank: Frequent Contributor
timestamp: November 28, 2018, 06:26:18 am
content: I have one of those. Its pretty well made and the resistors are all in cans. Its too big and sits in storage. I also have an ESI RV722 which is a lot smaller. Someday I may set them up for comparison testing. JRL came up with a way to validate one with far fewer measurements. Testing every step (10,000,000) would be an absurd task.

author: RobK_NL
author_rank: Frequent Contributor
timestamp: November 28, 2018, 03:11:41 pm
content: [shameless self-promotion]I happen to know there's a Fluke 720A for sale:https://www.eevblog.com/forum/buysellwanted/fs-(eunetherlands)-fluke-720a-kelvin-varley-divider/msg1882001/#msg1882001[/shameless self-promotion]
"Fake" HP AGILENT 10811A - Page 1
Forum section: electronics / general

author: jfphp
author_rank: Regular Contributor
timestamp: April 04, 2018, 04:36:31 pm
content: Hello,I am facing an operational OCXO mounted in an Agilent (not HP) recent 8662A with option 03 (specified low phase noise on the 640 Mhz output) : it is a 10811A box with the classical finger board connector but it has PN 1813-1304 and was made by OFC or Oak Frequency Control (PN MC6811X4-002W ?), bought by Vectron and Microsemi. Opening is very easy and it is a little double sided circuit made with smc comonents. Any idea ? Schematic diagram for curiousity ? Thank you

author: Vgkid
author_rank: Super Contributor
timestamp: April 04, 2018, 07:32:58 pm
content: From what I've seen hp.also used piezo branded ocxo's as well.

author: kj7e
author_rank: Frequent Contributor
timestamp: April 04, 2018, 08:53:59 pm
content: And Ovenaire Audio Carpenter, as well as others.Found a news article from 1986 related to both;SAN DIEGO — Oak Industries, awash in debt and near bankruptcy last year, began a comeback bid Tuesday by agreeing to acquire the Quartz Crystal Components Group of New York-based Electronic Technologies for an undisclosed amount.When the deal is completed, San Diego-based Oak will acquire three Electronic Technologies businesses that last year reported revenues of $18.7 million.The acquisition will "greatly enhance and broaden the scope" of Oak's existing McCoy Electronics operation, according to Oak Chairman E. L. McNeely. He described the acquisition as "the first step of our strategic plan to restructure Oak around its core companies."Included in the acquisition are Croven Crystals Ltd. a Canadian company located in Whitby, Ontario, that manufactures precision quartz crystal components; Houston Electronics, a Kane, Pa., manufacturer of hermetically sealed glass-to-metal enclosures for the quartz crystal industry, and Ovenaire-Audio-Carpenter, a Charlottesville, Va., company that manufactures crystal oscillators for the telecommunications and defense industries.More here;http://articles.latimes.com/1986-12-03/business/fi-296_1_oak-industries

author: analogRF
author_rank: Super Contributor
timestamp: November 16, 2018, 05:58:41 am
content: Quote from: jfphp on April 04, 2018, 04:36:31 pmI am also facing a dead ocxo with the exact same P/N (1813-1304) and made by OFC (same PN) in my 8664A. It's totally dead. I have taken it completely apart except the main oscillator can which is soldered and mounted on the inner PCB. I am testing it outside the unit with external power supply. Voltages and opamps all seem ok except there is no oscillation and 5 through hole pins of the oscillator 'can' are all at zero volt.A schematic would really help or at least a suggestion for replacement perhaps.the oven works because it gets hot and the current draw starts to drop from the initial 300mA on the 21V rail.in the block diagrams, there is a "switch" pin on the 6 pin connector that bring power to the OCXO from motherboard. I wonder maybe there should be a turn on signal coming in to turn this thing on and I don't have it...
Selection of toggle switch in DC voltage calibrator - Page 1
Forum section: electronics / general

author: pigrew
author_rank: Frequent Contributor
timestamp: November 08, 2018, 03:55:45 pm
content: I'm working on repairing myPPM 412 DC voltage calibrator(diode reference plus 6-digit KVD with battery power). Its 1V/10V range switch failed, and I need some help selecting a replacement.The existing switch is a DPDT toggle, with gold-plated contacts. It switches DC (low current, but probably ~10 V or so when open). It directly switches the range-selection resistors. The old switch failed open. It has a 1/4-in panel-mount bushing and a locking actuator, and is rated at 2A/240V + 5A/120V.Should I select (Brass)NiAu or (Brass)AgNiAu contact materials? I assume that AgCdO contacts are a bad idea for low-level signals because it would have a higher contact resistance or the low voltage wouldn't break down the oxide?Thanks,Nathan(PS: Once I repair the thing, I'll post some photos and my reverse-engineered schematics. Should the review go into the metrology or the test equipment forum?)

author: Magnificent Bastard
author_rank: Regular Contributor
timestamp: November 09, 2018, 04:12:07 pm
content: You will need a switch that is specifically designed for low currents (i.e. "dry contacts")-- other switches require a minimum current or they can fail prematurely. If the impedance of what you are switching is low enough (and the load impedance high enough), you could use a DPDT solid state switch, then use any switch on the panel to control the solid state switches.

author: vindoline
author_rank: Unknown
timestamp: November 11, 2018, 05:02:23 pm
content: I've usedthisswitch in the past with good results to repair the range switch in a Power Designs Precision power supply. The specs are gold plated contacts over silver.
Crest Factor, True RMS etc/ how to understand? - Page 1
Forum section: electronics / general

author: 001
author_rank: Super Contributor
timestamp: November 15, 2018, 10:25:05 am
content: Hi!Tell me please, how to understand Crest Factor and True RMS measurment?Can I read SQUARE wave voltage with meter of CF=3 and 6000 counts?

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 16, 2018, 05:46:50 pm
content: This might help-https://www.ecmweb.com/power-quality/crest-factor-key-troubleshooting-parameter

author: David Hess
author_rank: Super Contributor
timestamp: November 21, 2018, 04:18:06 pm
content: Crest factor is the ratio between the peak and RMS value. Since the peak value of a square wave is equal to its RMS value, it has a crest factor of 1 making it even easier to measure than a sine wave with a crest factor of Sqrt(2).

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: November 22, 2018, 01:03:42 am
content: Interestingly, one of the hardest things to measure accurately is noise.

author: David Hess
author_rank: Super Contributor
timestamp: November 23, 2018, 04:42:38 am
content: A good white noise source could have a crest factor of 10.https://noisecom.com/~/media/Noisecom/Crest%20Factor.ashx
Microwave, Ham Radio - Page 1
Forum section: electronics / general

author: mirzavanyaa
author_rank: Newbie
timestamp: November 07, 2018, 12:30:24 pm
content: I'm considering the 3 output DVR1 voltage reference, RS1 resistance standard and CS1 capacitance standards. So I'd be spending $600-750 depending on which models I got.. Are there comparable units I should look at or teardown photos of these?
Anritsu MG3642A Synthesizer .... Anyone have experience with this one? - Page 1
Forum section: electronics / general

author: saradr
author_rank: Newbie
timestamp: November 06, 2018, 06:44:16 pm
content: Anyone have any experience with the MG3642A (125Khz-2080Mhz)? I have error messages "rf amplifier abnormal".... Would like to have service manual (have the ops manual)Thanks, Chester
Lux (Light) Meters - Page 1
Forum section: electronics / general

author: Kenny Powers
author_rank: Contributor
timestamp: November 08, 2018, 04:29:13 pm
content: Does anyone have any information on what's needed and involved in calibrating Light Meters?https://uk.rs-online.com/web/c/?sra=oss&r=t&searchTerm=lux+meterThanksKP
calibration standards from www.ab-precision.de - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: November 05, 2018, 08:17:32 pm
content: I received a PM informing me of these and the lower end models look as if they might be very well suited to my needs. But google didn't tell me much.Does anyone have experience with these? I'm considering the 3 output DVR1 voltage reference, RS1 resistance standard and CS1 capacitance standards. So I'd be spending $600-750 depending on which models I got.. Are there comparable units I should look at or teardown photos of these?

author: Andreas
author_rank: Super Contributor
timestamp: November 06, 2018, 07:30:47 am
content: Hello,some discussion was already here:https://www.eevblog.com/forum/metrology/dvr1-voltage-reference/msg1406167/#msg1406167with best regardsAndreas
eBay USA made voltage references - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: November 05, 2018, 01:31:58 am
content: Does anyone here have any experience with these?https://www.ebay.com/itm/10-Volt-10-V-DC-Prec-Voltage-Reference-Standard-Nulled-to-Fluke-732A-or-732B/251756273626They seem rather too good to be true.

author: Kosmic
author_rank: Super Contributor
timestamp: November 05, 2018, 01:52:38 am
content: Read this firsthttps://www.eevblog.com/forum/metrology/calibratory-d-105-dc-precision-voltage-reference-standard/

author: rhb
author_rank: Super Contributor
timestamp: November 05, 2018, 03:31:28 am
content: Thanks! I read enough to not want one. It's interesting that it is no longer called a "Calibratory D-105". I'd guess so it is harder to check up on.I just ordered one of Doug Malone's 10 V references. It's 1/3 the price and has the distinct advantage of being a quality piece of work and not a nut job product.

author: Kosmic
author_rank: Super Contributor
timestamp: November 05, 2018, 02:51:21 pm
content: Good choice
Anyone with experience with Transmille Calibrators? - Page 1
Forum section: electronics / general

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: October 29, 2018, 09:22:35 pm
content: A Fluke 5502A is roughly the same cost ($20k) as the Transmille 3041A. The Transmille 3041A is nearly twice accurate in most ranges, has current to 30A, frequency to 10 MHz, resistance to 1 GOhm, includes a fixed inductance module (the Fluke 5502A does not have inductance), 3 year warranty (vs. Fluke 1 yr) and is less than half the cost for annual calibration. The Fluke 5502A is a Fluke - but there is nothing else that makes it a sell to me over the Transmille other than the weight the Fluke brand carries with it. Does anyone out there have any real world experience with the Transmille line of calibrators? I have used the Fluke 5502A and 5522A with no problems; however, I am looking for the best instrument to serve a newer laboratory (ISO 17025 accredited calibration laboratory, just haven't gotten the "source" standard yet). The accuracy, extended ranges, and lower cal cost are quite a selling point. I appreciate any and all opinions. Comparison sheet attached for any interested parties. Peace.Also want to add - I was told that the Army, NIST, NASA, and other NMI have been purchasing Transmille calibrators and meters as of late. I have confirmed with the Army that they have purchased. Another poster on this forum in Germany (I may be off here) posted a picture of one of the Transmille calibrators in a NMI they visited.

author: tggzzz
author_rank: Super Contributor
timestamp: October 29, 2018, 09:55:47 pm
content: What's the stability over time and temperature?

author: Echo88
author_rank: Frequent Contributor
timestamp: October 29, 2018, 10:09:12 pm
content: Extended Specs for both devices:http://www.transmille.com/file_upload/3041A-Extended-Specifications-V1-62.pdfhttp://download.flukecal.com/pub/literature/5502a___omeng0000_0.pdfI didnt work with transmille devices, so i cant comment.

author: itsbiodiversity
author_rank: Regular Contributor
timestamp: October 29, 2018, 10:26:23 pm
content: See Echo's reply, but they do publish stability in 2 yr which I like. I have attached the 3041A datasheet. I would appreciate your feedback on these specs.

author: Neilm
author_rank: Super Contributor
timestamp: October 30, 2018, 07:54:00 pm
content: We use them at work. They are good for the production lines but the calibration lab does have a Fluke as the main referance.
DM3068 calibration - Page 1
Forum section: electronics / general

author: jopl
author_rank: Newbie
timestamp: October 29, 2018, 09:49:21 am
content: Dear DM3068 gurus,doesn't someone of you know, how to calibrate DM3068 multimeter? There is the service guide for DM3000 available, where I can find entering password for calibration, but this is not unfortunately case of DM3068, where is just notice in service guide manual, that DM3068 does not support user calibration ... Is there any suggestion, how I could calibrate multimeter with with help of 5522A Fluke Multi-Product Calibrator, like in other multimeter models from Rigol? Thank you for anybody's reply in advance. jopl

author: bck
author_rank: Contributor
timestamp: October 29, 2018, 01:05:13 pm
content: try "DMCAL"thats what the manual for the DM3058 says (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-059c/1/-/-/-/-/DM3058%20Calibration%20Guide.pdf)

author: jopl
author_rank: Newbie
timestamp: October 29, 2018, 03:10:22 pm
content: Dear bck,thank you for your answer. Unfortunately there is no visible option of password in the "Utility" - "T/C" buttons sequence as well as no options "SecrOff" or "Cal" are there. I though DM3058 and DM3068 are very similar but as I can see now, it is different in this menu option. Or am I wrong or missing something in the beginning, i.e. within start of the system for example? Thx for reply. jopl
Alpha Electronics TLC(x) - Page 1
Forum section: electronics / general

author: Vgkid
author_rank: Super Contributor
timestamp: October 24, 2018, 03:03:58 am
content: These seem to have pretty decent specs for the price. What is your take on them, anyone used them?Datasheet:https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.trendsetter.com/v/vspfiles/assets/datasheets/Alpha%2520Electronics/TLA%2520TLC%2520Series%2520Rev10-29-2013.pdf&ved=2ahUKEwilt4Dyi57eAhUkh-AKHcmcC4oQFjAGegQIAhAB&usg=AOvVaw2ic_-0U52puTHFVipMgFdW

author: Echo88
author_rank: Frequent Contributor
timestamp: October 24, 2018, 09:53:03 am
content: I only know that Dr. Frank used FLCY-types in his Fluke 752-replica ->https://www.eevblog.com/forum/testgear/hp34401-measurement-of-linearity/msg358713/#msg358713"I used 104 identical metal foil resistors, FLCY from Alpha Electronics, 25kOhm, 0.1%, 0.14ppm/K typ. @ RT, available from rhopoint components Germany."Dont know if anyone used TLA/TLC though.

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 24, 2018, 11:11:05 am
content: I used the FLCY, as they were available from stock, with appropriate standard values (i.e. 120 Ohm, 1k, 12k, 13k, 70k) for the LTZ1000 circuit, and for a reasonable price, compared to the original Vishay BMF resistors. rhopoint components in GB had / have them in stock.Made good experience, as these parts seem to have less variance in T.C. specification than Vishay, see also Andreas analysis on these components.That was important for the build of the Hammon divider, as it lives from equal T.C. of its 100 constituents.Frank
[found] Rohde&Schwarz UPV, searching for 2.0 firmware - Page 1
Forum section: electronics / general

author: kikook
author_rank: Contributor
timestamp: October 26, 2018, 09:24:12 am
content: Just bought a not so perfect state second Hand UPV.The beast have a vey old 1.4 firmware. To upgrade it, I need the 2.0 firmware but R&S doesn"t provide a link to download it.For the moment R&S Europe didn"t respond to me.Is there anybody here who have the install disc and can make an image file of it ?The name is "UPV Audio Analyzer Firmware Upgrade 2.0.0", ident number 1406.0154.42Thanks !

author: kikook
author_rank: Contributor
timestamp: October 26, 2018, 12:02:41 pm
content: Just have a return of my mail to R&S.Nice service !

author: seebeck
author_rank: Contributor
timestamp: October 30, 2018, 10:53:28 am
content: I just used the UPL, it is a very good audio analyzer and the specification for low distortion opt of signal generator is so much better.
Hameg HZ186 4 Terminal Transformator Test Cable - Internal Circuit - Page 1
Forum section: electronics / general

author: michael_ng
author_rank: Newbie
timestamp: October 16, 2018, 07:51:12 am
content: Does anyone have a picture or schematic of the internal circuit of these testadapter for the HM8118 LCR-bridge?Are there any additional circuitry inside to make valid transformer measurements?Many thanks in advance.

author: F64098
author_rank: Regular Contributor
timestamp: October 16, 2018, 08:36:23 pm
content: Hello,when i read all accesible manuals, there is real nothing in this adaptor.The main thing of this adaptor is the description of the connectors, so that you connect the DUT in the right way.Best regardsFrank

author: branadic
author_rank: Super Contributor
timestamp: October 16, 2018, 09:12:34 pm
content: There is nothing inside, it is just a 4W connection to both terminals. I once disassambled one of them, as I had to develope an application specific test adapter.-branadic-
Schematic for: "Filter Trims Ultra-Precision Voltage Reference" article - Page 1
Forum section: electronics / general

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: November 02, 2018, 04:42:25 pm
content: Hi folks,This article:www.electronicdesign.com/energy/filter-trims-ultra-precision-voltage-referenceis intriguing, but the links to the figures do not work. Could not find in the wayback machine, either (probably pilot error).Has anyone archived the schematic??Thanks,Randall

author: Kleinstein
author_rank: Super Contributor
timestamp: November 02, 2018, 05:34:44 pm
content: I am not absolutely sure it is the picture from the article, but I think I have local copy.However the use of low pass filtering is limited to a voltage reference, as the interesting part is the very low frequency part, like below 0.01 Hz and this is hard to filter.

author: Echo88
author_rank: Frequent Contributor
timestamp: November 02, 2018, 05:44:30 pm
content: This particular circuit was already discussed here, if its of interest to you:https://www.eevblog.com/forum/metrology/(ft)-ltz1000a-fairy-tale-or-the-story-of-little-jumper/msg1190460/#msg1190460
Interesting service - custom resistor values - Page 1
Forum section: electronics / general

author: daqq
author_rank: Super Contributor
timestamp: September 27, 2018, 01:29:35 pm
content: I've been looking for something else when I came up upon this:http://www.vishaypg.com/foil-resistors/videos/?video=33Basically, with pretty simple tools (and the appropriate software), they can trim any resistance value. Which is cool.Do they sell the blanks (untrimmed resistors) to people? You could hand trim them yourself, in circuit. This would be particularly advantageous for situations where you have stuff like LM399 references that are stable, but not accurate. You'd trim the divider to a specific value, while avoiding trim pots (due to higher temp co.). After trimming you could put a layer of lacquer on them to protect them against moisture and such.

author: try
author_rank: Regular Contributor
timestamp: September 27, 2018, 02:38:37 pm
content: How close do you want to get to 10V?

author: GigaJoe
author_rank: Frequent Contributor
timestamp: September 27, 2018, 06:57:58 pm
content: use a filer trim yourself ... what the problem ...

author: babysitter
author_rank: Frequent Contributor
timestamp: September 27, 2018, 07:12:12 pm
content: Edwins resistor manufacture a.k.a. Ultrohm Plus doesn't care for E-series values, if you ask him for a 737,4 Ohm Resistor you will get it without a premium. This is where a 1355 Ohm resistor at work is from...If you try filing down, report!Best regardsHendrk

author: petemate
author_rank: Regular Contributor
timestamp: September 30, 2018, 09:29:37 pm
content: Im wondering if there is any sort of measurements included(As I have seen in this video:). That would be awesome and you wouldn't need calibration for e.g .a resistor box. Just buy 5 resistors and you have an awesome calibrated box. I know soldering could technically change the value, but thats still magnitudes of order better than what was possible before.

author: JohnWick7
author_rank: Newbie
timestamp: October 08, 2018, 03:51:21 am
content: I like this forum very much.
VisaNS (archived) or NI-VISA .NET API (sparse docs) or PyVISA for new project - Page 1
Forum section: electronics / general

author: jneudorf
author_rank: Newbie
timestamp: September 19, 2018, 03:22:48 pm
content: For a new project, I need to talk to <some generic visa measurement device> to sense currents, and also communicate with my homebrew product (using an FTDI cable) in order to calibrate it. At the moment, I'm using windows 10, but I'm not totally opposed to using Linux. I presume I'll eventually use something like a Chroma 6310A load, but at the moment, I only have an oscilloscope and RS232 DMM (UT61E); the load is something I'm negotiating to get.I've found various code to talk to things such as the Rigol DS1102E scope using the VisaNS API, but National Instruments has archived the documentation. The new NI-VISA .NET API seems to be what NI is pushing these days, but I can't find any examples that use it: they seem to be pushing their $4000 measurement studio to use a wizard to generate wrapper APIs.Does anyone have examples using the NI-VISA .NET API? Or should I use one of the other approaches? Which?For marketing purposes and/or impressing the boss it would be nice if there were a GUI, but it's not REALLY essential.

author: pigrew
author_rank: Frequent Contributor
timestamp: September 19, 2018, 03:27:31 pm
content: Personally, I use C# with the "new" IVI .Net VISA library. The advantage is that it is compatible with both NI and KeySight VISA software.I have a (buggy) exampleon GitHub of a program to control some HP power supplies.

author: JohnPi
author_rank: Regular Contributor
timestamp: September 30, 2018, 04:03:24 pm
content: I use PyVISA for these types of tasks. It can easily communicate with instruments on GPIB, RS232 or USB. It'll work in Linux, OSX or Windows. You'll have to use Python which has its quirks, but pretty easy to get going.I suggest you start with INSTRUMENT.query("*IDN?") type statements to confirm connectivity to the VISA gear. For your home-brew RS232 (which won't have VISA), you can send and receive strings via the serial port.

author: dl1640
author_rank: Regular Contributor
timestamp: October 02, 2018, 11:37:44 am
content: i am learning Python and installed Python 2.7 for windows,i think i will learn PyVisa after i grasped Python fundermantals.currently i use another api to control instruments (GPIB, RS232, VXI, USBTMC) in vba.

author: petemate
author_rank: Regular Contributor
timestamp: October 03, 2018, 11:31:00 am
content: Quote from: dl1640 on October 02, 2018, 11:37:44 amWhy python 2.7? It's old and not recommended anymore. Go with 3.7.Also, another vote for pyvisa.

author: dl1640
author_rank: Regular Contributor
timestamp: October 03, 2018, 11:56:22 am
content: Quote from: petemate on October 03, 2018, 11:31:00 amthanks,I just learning with online instructions and intended to start with a relatively older version. and I would probably change to 3.x in the near future.anyway, there will be no huge project for me, just need to talk to the instruments, data logging, file manipulating etc.though VBA works just fine i found Python kind of smarter than vb in syntax.
Australia was once guardian of the Ohm. (plus some humorous fees) - Page 1
Forum section: electronics / general

author: intabits
author_rank: Frequent Contributor
timestamp: October 04, 2018, 10:53:11 pm
content: While perusing their site, I was surprised to see that Australia's National Measurement Institute was for a time, the world's custodian of the Ohm.Elsewhere, in their amusement section, I found this collection of gems:-I would have thought $3270 for measuring a resistor would be more than enough, but no, they need that extra 33 cents.They are after all, masters of precision - they are able to determine the fee to 3ppm.

author: lowimpedance
author_rank: Super Contributor
timestamp: October 05, 2018, 01:44:48 am
content: Quote from: intabits on October 04, 2018, 10:53:11 pmlolThe Australian "gov.mt" are always up for a laugh , usually when not trying to !.

author: Vtile
author_rank: Super Contributor
timestamp: October 05, 2018, 08:21:16 pm
content: It might not be the coincidence that the AC/DC is from Australia after all.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: October 05, 2018, 09:15:58 pm
content: Quote from: Vtile on October 05, 2018, 08:21:16 pmAcca-Dacca were noted for doing " dirty deeds done dirt cheap" I don't see the connection.
Building a resistance reference box with VHP100 series resistors - Page 1
Forum section: electronics / general

author: voltlog
author_rank: Regular Contributor
timestamp: September 27, 2018, 04:51:59 am
content: I actually went ahead and built the resistance reference box for which I was asking thisquestion regarding the binding posts. I think it turned out OK, but now I am searching for a local calibration lab to have this measured because the values that we're initially measured on the resistors themselves before soldering them have changed slightly. It might be due to the thermal/mechanical stress and also because I introduced some resistance with the binding posts and the connections.Would you recommend to wait a few weeks, a month? before having it measured at a cal lab? I'm thinking the values might take some take to settle now after they've been subjected to the thermal stress through soldering?There is one important thing that would have been better if done differently, as viewers commented on the video. I should have placed the upper force terminal to the end of the bus bar to the left, and I should've placed the sense terminal to the other end of the bus bar at the right. This way there would have been no current flowing through the sense part of the circuit. Practically I don't know how much that is going to affect my measurement, considering the 1mm thickness of the bus bar.Here is a video of the build.
Coleman 37A - Page 1
Forum section: electronics / general

author: Floopy
author_rank: Regular Contributor
timestamp: September 26, 2018, 02:40:12 pm
content: My equipment source has supplied me with this almost new Coleman 37A PH meter. The carrying case is made of cowhide and everything else is very clean. It has a power receptacle for running of 120VAC, but it also has an internal cadmium battery. The battery still had a charge? Anyway, everything seems to work. Unfortunately it dind't come with a probe?Does anybody know where I can find a probe for a device like this? I took a picture of the ports, but I couldn't find anything online. Are all PH probes created equally?Also, should I remove the cadmium battery? It hasn't leaked.I'll get some better tear-down photos once I can. I took these ones while I was taking it apart.

author: Floopy
author_rank: Regular Contributor
timestamp: September 26, 2018, 02:41:41 pm
content: A little more...

author: Floopy
author_rank: Regular Contributor
timestamp: September 26, 2018, 02:43:06 pm
content: Last of it. The maximum size is 2Mb, so I have to break it up.
Datron 4910 PWM-Schematics - Page 1
Forum section: electronics / general

author: Echo88
author_rank: Frequent Contributor
timestamp: November 05, 2016, 10:19:29 pm
content: Does anyone have a working link to the schematics of a Datron 4910 or a similar reference device where PWM is used to converte the 7V to 10V? All my google-fu led me to no useful result.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: November 06, 2016, 12:54:09 am
content: Try herehttps://doc.xdevs.com/doc/Datron/4910_4911/I am not sure if it has all the schematics.

author: Echo88
author_rank: Frequent Contributor
timestamp: November 06, 2016, 01:00:03 am
content: Thank you!

author: kees0_15
author_rank: Newbie
timestamp: September 24, 2018, 09:52:29 am
content: Hi,looking for Datron user's manual 1081 and trying to understand the PWM-divider in the Datron 4910 I would like to pick up the schematics.But the suggested link does not work. Any suggestion?Thanks in advance,CGM de Bruijn (kees0_15)

author: TiN
author_rank: Super Contributor
timestamp: September 24, 2018, 11:30:21 am
content: Correct link.
How can I set the oscilloscope probes as matched probes (R&S HMO3002) - Page 1
Forum section: electronics / general

author: ogulcan
author_rank: Newbie
timestamp: September 14, 2018, 07:56:59 am
content: Hi,I want to test the switching regulator output of my circuit using the simple methodology described in the page 18 ofhttp://www.ti.com/lit/an/snva559a/snva559a.pdf,which is attached as remove-common-signal.PNG.I have a Rohde&Schwarz HMO3000 series (HMO3002) oscilloscope, and I could not make my probes matched, so when I substruct the channel 1 signal from channel 2, I cannot get rid of the spikes, which I think is due to the fact that my probes are not matched probes.How can one set two oscilloscope probes as matched probes?Cheers,Ogulcan

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2018, 09:05:15 pm
content: This was easier to do with the analog oscilloscopes and the oldest DSOs which did the invert and add in the analog domain.You can evaluate lots of probes to find the best matched set but keep in mind that the oscilloscope vertical inputs contribute their own mismatch so the probes always need to be attached to the same vertical inputs.In practice the best compromise is to use 10x probes and:1. Apply suitable common mode square wave signal.2. Adjust the compensation of each probe.3. Switch to invert and add mode so the test signal becomes common mode.4. Adjust the compensation of one probe and the vertical gain of one channel for best common mode response.Note that x1 probes have no compensation adjustment but the vertical gain adjustment still needs to be done because of gain mismatch between the vertical inputs.

author: ogulcan
author_rank: Newbie
timestamp: September 20, 2018, 02:09:20 pm
content: Thanks for your answer.It says 1:10 on the connector of my probes, so I guess they are X10 probes, I saw a hole in the connector of the probes and tweek it a little bit, it changes the amplitude, but does not seem like changing the compensation.You can see the probes I'm using in here:https://www.tequipment.net/Rohde-&-Schwarz/HZ355/Standard-/-Passive-Oscilloscope-Probes/I guess I need a matched set

author: David Hess
author_rank: Super Contributor
timestamp: September 21, 2018, 02:31:26 am
content: In order to see the compensation, a low frequency square wave test signal is required. 1kHz is typical.After compensating the probes, the same or higher frequency test signal is applied to both and the compensation and vertical gain of one probe is adjusted in differential mode for the best or least common mode response.
Absorption plate set for gamma radiation - Page 1
Forum section: electronics / general

author: Physikfan
author_rank: Regular Contributor
timestamp: July 10, 2018, 10:47:38 am
content: On Ebay I found an absorption plate set for gamma radiation:

author: babysitter
author_rank: Frequent Contributor
timestamp: July 10, 2018, 12:40:48 pm
content: Genosse Abschirmski!

author: CopperCone
author_rank: Super Contributor
timestamp: July 11, 2018, 01:02:19 am
content: The finish on that lead plate looks trashy. Give it a gentle sanding over and a coat of polyurathane.

author: InductorbackEMF
author_rank: Regular Contributor
timestamp: September 18, 2018, 06:57:19 am
content: Is that plate just made of lead? If so with the amount of lead i have i could build two boxs haha.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 19, 2018, 02:46:17 pm
content: The plated have a defined thickness. So one could add a thin layer of varnish, but should not remove much oxide.The plated are made from different materials: lead, aluminum, copper and iron. The list of contents (first picture) gives a good list.This set looks like made for schools / education, so nothing extra accurate.
Are these LM399H special in any way ? - Page 1
Forum section: electronics / general

author: DC1MC
author_rank: Super Contributor
timestamp: September 13, 2018, 10:43:31 pm
content: Hello dear volt nuts, I want to refresh the reference on some older DMM and found these NOS LM399Hhttps://www.ebay.de/itm/LM399H-25-Stk/132762592007The seller claims them to have a date code of 96 something and the only visible one has a code of 97xx.The part costs in qty of 25 something like 5,7 EUR on Mouser, do those (alleged) 20yrs storage time warrant the asked price ( almost double) because of increased stabilityor it just BS ?Many thanks,DC1MC

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: September 13, 2018, 10:51:12 pm
content: There doesn't appear to be anything wrong with these but LM399 chips do not age significantly just lying around, they really need to be under power to be aged. In my opinion, these have no significant advantage over buying current dated chips from Linear Tech, they will require just about the same amount of aging under power.

author: Wolfgang
author_rank: Super Contributor
timestamp: September 13, 2018, 10:56:53 pm
content: Hi,aging on the shelf is very slow and not used in stabilizing a reference. What they do is:- power them up at elevated temperatures- or, even better, run them thru temp cycling over their full temp range while powered up.The 4ppm LTZ1000s are made this way, I heard. Like vintage wine the stored on ships to age better

author: GigaJoe
author_rank: Frequent Contributor
timestamp: September 14, 2018, 04:14:02 am
content: for some reason they sorted in 3 groupsthen .. it national , not a linear, It possible it " Chinese new" that a used , LM399 recovering to a new state (changing legs and galvanizing to gold like state, and packaging to the new plastic case as NS product.I haven't heard about completely fake product, as it difficult to reproduce due to heating element. ( but LTZ1000 does). In overall nothing wrong. but: a. chance it less stable due to external influence like temperature or mechanical forces on legs. plastic package a flimsy tend to open ...I use to bought 10 and keep for 6 month under 160C , heater off, legs are became oxidized , then 2 month in a normal heater on state, after all 4 of them shows 0ppm voltage change in last 30 days period. ( i use 3 units HP3456 ). I may conclude it drifting less then i can measure, like 2-3ppm/1Kh. worse case 17ppm in last month -1 , and 3-6ppm the rest. I assume, it was already used, probaly high temperature do some relieve of stress, that was done during reconditioning ... just guess.
Solid state dehumidifer - Page 1
Forum section: electronics / general

author: texaspyro
author_rank: Super Contributor
timestamp: September 14, 2018, 02:47:41 am
content: Bigclive just posted a video on a no-moving-parts ionic membrane dehumidifier doohicky. Seems like it might be handy for implementing a humidity control/stabilization system for a precision gizmo mounted in a box.
Ebay Voltage References for 2018. Any troubles? - Page 1
Forum section: electronics / general

author: 001
author_rank: Super Contributor
timestamp: September 07, 2018, 08:13:27 am
content: HiI know, its another tread for china references, don`t be angry pleaseI got my own ad584 based unit two years agoIt`s fineChip looks like real old recycled ICBut now 2018 and same (?) references still avaliable! Where they get billions quantities of recycled IC`s?Is NOWDAY "AD584" are fake?What is the safe way for 2018 to get some reference from ebay? AD588? LM399? etcThanx!
what burden voltage is ok for panel ampermeter? - Page 1
Forum section: electronics / general

author: 001
author_rank: Super Contributor
timestamp: September 04, 2018, 06:32:24 pm
content: Hiwhat burden voltage is ok for panel ampermeter?Is it standartisied someway?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 04, 2018, 06:39:00 pm
content: IFAIK there is no real standard. Values of around 50 mV are good for higher current. With small currents something like 200 mV was very common with digital ones, the analog ones tend to have a little lower burden.

author: Gyro
author_rank: Super Contributor
timestamp: September 04, 2018, 08:38:45 pm
content: The old analogue meter 'standard' was 75mV, in fact you can still find plenty of those [Edit: shunts] on ebay.

author: try
author_rank: Regular Contributor
timestamp: September 05, 2018, 09:15:10 am
content: Hello 001 and Kleinstein,Quote from: 001 on September 04, 2018, 06:32:24 pmthe question ist incomplete. You do not mention the intended current range to be measured.Furthermore you should consider how far a voltage drop on the panel meter affects your device unter test.You might want to try this out measuring the start-up current on a 2,5'' harddrive - don't have a better example in mind.Quote from: Kleinstein on September 04, 2018, 06:39:00 pmWhat is "high current", what is "low current" in quantitative terms?Regardstry

author: Wolfgang
author_rank: Super Contributor
timestamp: September 05, 2018, 09:05:05 pm
content: I would say that there was no fixed standard, but a burdon voltage of a few ten mV (IIRC 60mV) was common.A lot of industrial shunts up to a few 100A are made for several 10mV of meter voltage at full scale.
ESI RV722 KVD - why 1.1 value on first decade - Page 1
Forum section: electronics / general

author: meandeev
author_rank: Regular Contributor
timestamp: September 08, 2018, 05:26:50 pm
content: Hi,I need some help for understandig (and correct repairing) an ESI RV722 dekavider that I bought "as is".At the picture one can see, that the highest decade has "1.0" and "1.1" markings on the wheel.At this decade a c-clip was missing on the axis. With that c-clip (I added one, in my opinion "normal operation") these values can not be reached, because of stoppers.Without the c-clip I can push the axis a little bit so that these stoppers are overruled and the „1.0“ and „1.1“ can be reached. These stoppers don´t exist at lower decades, but there are no markings at these positions.I made a schematic of the switch posisitons in the next picture. What is not seen in the pictures, that both inputs of the following decade can be reached on internal binding posts.So why these switch positions exist? Calibration? Why these can not be reached on the first decade in normal operation?

author: JS
author_rank: Frequent Contributor
timestamp: September 08, 2018, 06:03:35 pm
content: Check fluke 720A data, it also has 1.1 in the first decade and there's a ton of info online for it, likely for calibration.JS

author: TiN
author_rank: Super Contributor
timestamp: September 09, 2018, 03:35:26 am
content: 1.1 is so you can get 1.0 value off bit higher input voltage.

author: dacman
author_rank: Frequent Contributor
timestamp: September 10, 2018, 02:34:55 am
content: Max setting of the RV-722 should be .999999X. Settings of 1.0 and 1.1 for the MSD are not valid.A setting of 1.1 (or actually 1.099999X) is available on the Fluke 720A and IET KVD-700, but these units have both a 1.0 input and 1.1 input.There is a schematic of the RV-722 on the IET website (although the manual does have mistakes).The unit should have a panel with a window over the dial indicator and you should never see either the 1.1 or 1.0. It doesn't surprise me that it was constructed that way (ESI is not the only manufacturer that has done that or something similar).At dial setting zero, the dial should be connected to the bottom of the first resistor and between the 2nd and 3rd resistors (it should bracket the 1st and 2nd resistors). When set to 1, it should be connected between the 1st and 2nd resistors on one end and 3rd and 4th resistors on the other (it should bracket the 2nd and 3rd resistors), etc

author: meandeev
author_rank: Regular Contributor
timestamp: September 10, 2018, 05:31:57 pm
content: I know the schematic on the IET website and have also older versions. But I couldnt find a hint for these values.As I wrote, the 1.0 and 1.1 cannot be seen in normal operation because of the stoppers at this decade seen in my second picture.So I made the schematic from the device itself.The device is working as a 11:1 divider for the setting of 1.1 and as a 11:10 divider for 1.0 - regardless of the settings of all other decades.So I´m looking for a reason of this construction.
Need help (0.03%+2d)/0.005%=????????? - Page 1
Forum section: electronics / general

author: 001
author_rank: Super Contributor
timestamp: September 05, 2018, 11:42:37 am
content: HiSorryI`m old but havent any grafuate in electronixIf I read voltage with (0.03%+2d) voltmeter around 0.005% resistor what is result current tolerance?Thanx!

author: mzzj
author_rank: Super Contributor
timestamp: September 05, 2018, 01:02:14 pm
content: Quote from: 001 on September 05, 2018, 11:42:37 amAssuming that that you are measuring current shunt resistor..Simple answer: you can pretty much ignore the resistor tolerance, voltmeter accuracy is dominating the accuracy because its over 6 times worse than the current shunt.Long answer: you don't want to know( about 16 pages of explanations, two dozen unknown variables and slight headache)

author: awallin
author_rank: Frequent Contributor
timestamp: September 05, 2018, 01:08:01 pm
content: how about the 5th row in the table here:https://en.wikipedia.org/wiki/Propagation_of_uncertainty

author: try
author_rank: Regular Contributor
timestamp: September 05, 2018, 01:19:13 pm
content: Quote from: 001 on September 05, 2018, 11:42:37 amMe neither, but I am maybe not so old.QuoteWithout telling the forum the number of counts, the measurement value and range used nobody can give you an exact figure.With no correlation effects the uncertainties will add up so that the resulting uncertainty is at least 0,035%.Low readings in a range will make that figure explode due to the increasing weight of 2d.=> The value of 0,035% is pretty meaningless for you.Regardstry
Siemens Multizet A1000 - Page 1
Forum section: electronics / general

author: ac_dc
author_rank: Contributor
timestamp: September 01, 2018, 09:39:56 am
content: Hi!I have a Multizet A1000 from Siemens; when adjusting the pointerto the 0 position with the E-front rotary switch I can not do thatpointer to 0. According to instructions one should then internally with theR41 20K do the zeroing. I would complete the deviceDismount to access even on the bottom of the motherboardto have. Despite the schematic it is confusing which the R41 really isis ...greetings

author: borghese
author_rank: Regular Contributor
timestamp: September 01, 2018, 05:19:35 pm
content: R41 is the coarse adjustment and R40 the fine.Probably some components are aged a lot

author: ac_dc
author_rank: Contributor
timestamp: September 01, 2018, 05:41:15 pm
content: But they have to be there ... maybe different revisions? While looking at the board I seeunfortunately only a single IS1 (ICL 7614) and left side centerat the T4 (167B).But there where the "E-Poti" is located R40 2,5K next to it is a potibut definitely not R41 20K and also no S2 ICL 7614.

author: ac_dc
author_rank: Contributor
timestamp: September 05, 2018, 10:23:19 pm
content: Does anyone have such a multimeter and what can contribute?