hybridfree/eevblog-posts huggingface dataset:
Better hacker API for USB based test equipment: Keysight vs NI? - Page 1
Forum section: electronics / general

author: AaronDangerMartin
author_rank: Newbie
timestamp: October 07, 2022, 09:27:59 pm
content: I am considering Keysight's modular and usb based devices for mixed IO as part of a test setup. I'm wondering if they have a good set of drivers like NI's DaqMX set of drivers for data acquisition. I'm particularly interested in automating data acquisition using .NET or Python.Overall how does Keysight'sdriver supportfor desktop based equipment compare to NI's?(I am NOT wondering if Keysight has a competitive product to LabVIEW or TestStand, but maybe that's another thread, IDK)Should I install the Keysight USBDaq driver? It doesn't have any documents, does it have an API?Should I install Keysight AMM?

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 07, 2022, 11:13:17 pm
content: The best USB instrumentation API is as follows:Take USBPut in trashUse ethernet insteadDrivers are the reason. Both Keysight and NI are bad at drivers. Really bad. Trusting them with apps is a stretch, trusting them in your kernel is a Hell No. Just towards the beginning of the pandemic there were ~6 months or so where the Keysight IO Libraries would lock up our lab computers for 1 second every 10 seconds. Hard lock -- the mouse did not move, the screen did not update, IO did not happen, the keyboard USB connection would timeout and rediscover on the other side, it was bad. I didn't even know that was possible in modern Windows, but it is. Of course, usually things aren't that bad, usually you just have to jump through hoops to hunt down gigabyte-scale packages, give up personal info, download several to find what is compatible with your instrument and computer, and be ready to rollback driver updates or OS updates if one breaks the other, which it absolutely will.Ethernet+python avoids these problems. Just pip install pyvisa, pyvisa-py, and maybe pyvxi11 and you're off to the races. No drivers, no registration, no licensing, no divulging personal info, no compatibility dance, it just works, and interactive graphs and gui tools are just an "import" away.

author: Bud
author_rank: Super Contributor
timestamp: October 08, 2022, 03:33:05 am
content: Then pray that next Python release do not break your application.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: October 08, 2022, 04:24:22 am
content: Python breaks less often (YMMV) and is about 100x faster to check each version. Also: Docker exists. Artifactories exist. VMs exist. All of the modern infrastructure for dependency control and risk mitigation Just Works if you use python and ethernet, but it's a fight every single time if you use binary drivers or USB. I'd say you have it exactly backwards: NI & Keysight & USB are all stuck in the "install and pray" era. Python and ethernet are not.You're gonna have to swing harder than that to convince me USB T&M belongs anywhere except the trash can
How to reduce noise when measuring between voltage references? - Page 1
Forum section: electronics / general

author: Victorman222
author_rank: Regular Contributor
timestamp: October 03, 2022, 01:07:11 am
content: I'm trying to measure between two zener vrefs using my newly acquired HP3478A to characterize one diode by varying its current to observe change to tempco in my temperature range.Im a bit worried by the last 2 digits (1uV and 100nV) of the 5.5 digit reading on the 30mV range are completely random. My setup is coax cable going into banana plugs into dmm and soldered to opamp output on the other side. Im trying to figure out where this noise is coming from but having no luck. I tried replacing 2 cables by one coax, soldering directly to op amps, twisting the long(in order to put into thermal chamber) second diode cable.Your advice would be greatly appreciated!

author: MasterT
author_rank: Frequent Contributor
timestamp: October 03, 2022, 02:01:36 am
content: Try noise reduction, simple RC 10k + 1000 uF (Low Leak !).

author: Mickle T.
author_rank: Frequent Contributor
timestamp: October 03, 2022, 05:47:04 am
content: The OP37 (KR140UD26A) is not unity-gain stable and can oscillate in this configuration.

author: Andreas
author_rank: Super Contributor
timestamp: October 03, 2022, 06:14:45 am
content: Hello,can be too many reasons in your case:- OP37 is not unity gain stable so the cirquit may oscillate (try a OP27 instead?)- Same would apply for too much capacitive loading of the OP-Amp (coax cable length?)you may want to have a cirquit with capacitive isolation- integration time of DMM too short?but even with 100 NPLC on my 34401A I have 0.3-0.5 uVpp noise in 100 mV rangeand with the K2000 and 10 NPLC it is around 0.7-1 uVpp.- missing isolation from air drafts around the zeners.- EMI-Sources like mobile phone, WIFI, USB cables near the setup?- I would put all the setup at least on a metal plate against EMI (connected short to the housing of the DMM).(better would be to put the whole setup in a tin can)- and simply the noise of the zener could be also high.with a typical zener in a 10 Hz bandwidth you already have 4-6 uVpp on the 10V output.Of course the integration time (reducing the bandwidth) of the DMM would filter some of this noise out during measurement.with best regardsAndreas

author: jonpaul
author_rank: Super Contributor
timestamp: October 03, 2022, 07:05:17 am
content: No surprise on this very old meter, perhaps out of calibration?Suggest Tests...1. .place gold shorting plugs, see noise, digits for zero input2. Use standard cell, or any fresh battery eg 1.5v AA, D cell, wire up direct to the gold plated banana plugs, with copper wire, see digits and stabilityCheck meter specs for ENOB, accuracy, résolution, noise.Jon

author: Victorman222
author_rank: Regular Contributor
timestamp: October 03, 2022, 10:11:51 am
content: Thank you very much for the sound advice. I measured opamp output and yes it was oscillating. Will save up and get something like OP07.
Characterising analog switch charge injection - Page 1
Forum section: electronics / general

author: sahko123
author_rank: Frequent Contributor
timestamp: October 09, 2022, 01:12:19 am
content: I'm having issues trying to measure the charge injection of my TMUX1134. The plan was to characterise it for different bipolar power supplies (3.3V and -2V for example) to try and reduce the charge injection.To start I tried replicating the datasheets claims and could not get any decent reading. ATM i have one end of the switch open with the other tied to ground through either 10k resistor or just directly. The drain end of the switch has a 100pF cap and a scope probe going back to a Rigol DS1154Z. Is it a case of equipment or my setup? AFAIK i should be getting several mV differences even for tiny charges given the small capacitance but i get no change over any range of power supplies or caps.How would ye go about measuring such small charges and what could I be doing wrong?I'm trying to fill in the gaps in the graph below.

author: Kleinstein
author_rank: Super Contributor
timestamp: October 09, 2022, 10:50:47 am
content: Near ground level the charge injection is supposed to be quite small (e.g. more like 0.1-0.5 pC range) so the voltage in the 100 pF capacitor would only reach some 1-5 mV. This may be hard to see with a typical 10:1 probe. The variations with the supply also seem to be quite small.To get a better resolultion / less noise, one could think about an extra amplifer (e.g. x10): this can be be higher impedance to allow a reduced bandwidth (slower response) and this way less noise.In the extremes one would average over multiple cycles.A point to check is if the switch is actually switching, e.g. the right control signal and the EN pin correct ?
Material of Fluke standard resistors.  - Page 1
Forum section: electronics / general

author: NaxFM
author_rank: Regular Contributor
timestamp: October 04, 2022, 05:54:15 am
content: Do you happen to know what material Fluke uses to make their standard resistors?I saw that inside the box there is a combination of series and parallel resistors with positive and negative temperature coefficients, so that summing them gives a nominally zero temperature coefficient.I have doubts about the negative coefficient. From what I've found the only suitable material with negative coefficient is constantine, all the others like simple nichrome wire have positive coefficient.

author: DavidKo
author_rank: Frequent Contributor
timestamp: October 04, 2022, 07:21:06 am
content: The thermal expansion of substrate will have also influence on the coefficient.Example of resistors with different thermal coefficient are for example Vishay E102Z and E102 - check the datasheet.

author: alm
author_rank: Super Contributor
timestamp: October 04, 2022, 08:50:30 am
content: I'm pretty sure it's Evanohm. Evanohm is available in both positive and negative temperature coefficients depending on the heat treatment:https://www.carpentertechnology.com/alloy-finder/Evanohm-RThey would have different spools, measure the tempco and make different resistors with different temperature coefficients. I believe the final tempco can only be measured once the resistor is wound and terminated because it also depends on stress on the wire.Search for posts by Edwin Pettis to learn more about precision wire wound resistors.

author: trobbins
author_rank: Frequent Contributor
timestamp: October 04, 2022, 12:09:47 pm
content: The 895A-303 pcb (895A Differential Voltmeter - Kelvin-Varley board assembly) I recently checked had 19.999k resistor pairs marked FHIP0.5 and FLIN0.5, and +/-0.01%. As I understand it, the P0.5 and N0.5 markings relate to +0.5ppm and -0.5ppm batched parts, and I presume the FHI and FLI relate to above and below tolerance batched parts. Other known markings are P1.0, and N1.0 pairs. I'd anticipate parts were individually connected into a balanced bridge and galvanometer deflection used for batching.

author: RoadDog
author_rank: Regular Contributor
timestamp: October 06, 2022, 04:14:37 pm
content: Fluke uses several different types of wire depending on the application. I’ve seen how they’re made. It’s quite the process. All their precision resistors are built by hand. The wire racks are full of many different types of wires and there are different heat treating processes and other things they do depending on the resistors being made. All TC’d to each other into matched sets after being built. I don’t recall which wire they use for the standard resistors. Didn’t pay attention to brand or size. Just marveled at the amount of knowledge in that part of the factory.
Read and restore calibration constants from a HP 34401A - Page 1
Forum section: electronics / general

author: e61_phil
author_rank: Frequent Contributor
timestamp: August 09, 2018, 06:55:04 am
content: Hi,As shown here in the forum, for many meters some (undocumented) functions exists to read the calibration data via GPIB.Does anyone know, if such commands exists for the 34401A? I can't find anything until now.Best regardsPhilipp

author: meandeev
author_rank: Regular Contributor
timestamp: August 13, 2018, 08:21:35 pm
content: Hi,I did it on the hardware way with a test-clip on the eeprom (see the picture), but you have the unit switched on and the processor in "endless" reset, so that its pins are in a high impedance state.I used different test clips at the processor seen in the picture, that are connected with a 1k resistor.Then I used a GQ-4X programmer (choose 93C66B-Device with 16bit NOT 8bit).So you can read and write the eeprom.I´m also keen on: Is there a different way to read the constants (via HPIB or serial)?best regardsRonny

author: JohnPi
author_rank: Regular Contributor
timestamp: August 16, 2018, 01:54:20 am
content: There are apparently PEEK and POKE commands that might be able to read memory -- however I have never seen any documentation beyond this -https://www.keysight.com/main/editorial.jspx?cc=US&lc=eng&ckey=1000001267:epsg:faq&nid=-31895.536880933.02&id=1000001267:epsg:faqwhich shows how to enable a 10 mA AC range.

author: Hydron
author_rank: Super Contributor
timestamp: September 27, 2022, 10:17:37 am
content: A quick update to this topic - with the help of some other forum members and other old threads I've managed to do some EEPROM hacking to enable some hidden functions on post-07-xx-yy 34401A FW, and one of the discoveries was a method for saving the EEPROM contents (inc. calibration table) without opening the case:https://www.eevblog.com/forum/testgear/hp-agilent-34401a-hidden-menu/msg4436983/#msg4436983As of yet we haven't figured out how to write arbitrary values to the EEPROM without opening the case and connecting a programmer, but it may still be of interest here as at least you can get a quick backup. Would be best to whip up a script to do the work - I've already got my EEPROM dump from connecting a programmer to it, so haven't gotten around to writing one myself.As for the hidden functions, tl;dr is that there are 3 EEPROM bits (plus a checksum update) that if set allow for saving and recalling mode settings etc. (inc. on power up), a temperature measurement option (thermistor, RTD or thermocouple) and finally a "SCALE" option in the maths menu that lets you scale and offset readings without involving a computer.
Agilent 34401A 1% error on AC volts?  - Page 1
Forum section: electronics / general

author: mzzj
author_rank: Super Contributor
timestamp: September 24, 2022, 10:16:44 am
content: I'm not sure if this belongs more to repair or metrology but anyways..34401A failed on AC volts calibration at 50hz with really big error (1% low on all voltage ranges)Adjustment routine runs fine until adjustment point at 10Vac 10hz give error 733 "AC low frequency convergence failed"Manual wont tell more than that about error 733.Any ideas or has someone actually stumbled on the same problem?Oddly the VAC range measures ok-ish at 10Hz with less than 0.1% error and 1kHz is spot on.There is a dip around 50Hz on all ranges and it is about 1% of reading.

author: strawberry
author_rank: Super Contributor
timestamp: September 24, 2022, 01:38:57 pm
content: seems high pass filteroscilloscope and ac amplifier up to RMS converter

author: Gyro
author_rank: Super Contributor
timestamp: September 24, 2022, 04:55:07 pm
content: I don't know the internals of the 34401A in any detail but is it possible that (a section of) a DC mode line frequency rejection filter is wrongly switched in?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 24, 2022, 05:07:31 pm
content: The 34401 does not have an extra line rejection filter. The CMRR is just from using multiples of the power line period for the integration.The rather large error looks a bit like a defect of some kind, though a slightly odd one.The lower frequency end could be effected by AC coupling capacitors and the filter capacitor at the RMS converter.There filter at the RMS converter has 2 settings and the switching there could be wrong or defective.The amplifier / divider part could be checked with the scope and a low frequency (e.g. 20 Hz) square wave.Depending on the range different parts of the amplifier are used or not. So some defects may only effect some ranges.

author: mzzj
author_rank: Super Contributor
timestamp: September 26, 2022, 01:32:01 pm
content: Measured at 50hz and 1khz the voltage response up to rms converter seemed good (measured over R315)Things got bit weird after the rms converter: error seemed to do something with Q301, turns out it gets 0v or 2.7v gate drive depending if <200hz filter is selected or not.2.7v gate drive didn't make sense, U304 (DG4011) was driving the output pin from 0 to 15 volts. -->desolder the Q301 MTD3055VL mosfet.G-S resistance measures 2-3kOhm--> toasted-->replace with physically larger TO-220 3055VL mosfet.Seem to work fine now, now I'll just have to take this back to cal lab and run full calibration/adjustment cycle

author: strawberry
author_rank: Super Contributor
timestamp: September 26, 2022, 03:55:29 pm
content: that TH part will definitely fly off by first chance including PCB traces

author: mzzj
author_rank: Super Contributor
timestamp: September 26, 2022, 04:30:41 pm
content: Quote from: strawberry on September 26, 2022, 03:55:29 pmFairly large pads for the original TO252 and I'm not planning to use this in cement mixer.

author: strawberry
author_rank: Super Contributor
timestamp: September 26, 2022, 08:43:56 pm
content: been there
LM399 10V reference  - Page 1
Forum section: electronics / general

author: strawberry
author_rank: Super Contributor
timestamp: September 21, 2022, 07:12:37 pm
content: looking for divider resistors 1:2 , reliable sourcehttps://www.ebay.com/sch/i.html?_dmd=2&_dkr=1&iconV2Request=true&_ssn=hifi-szjxic&store_cat=10809269012&store_name=hifiaudioic&_oac=1

author: iMo
author_rank: Super Contributor
timestamp: September 21, 2022, 10:08:06 pm
content: Which one is closest to 0.4184397??

author: MegaVolt
author_rank: Frequent Contributor
timestamp: September 22, 2022, 10:20:43 am
content: https://ssl.pepas.com/hifi/dividers.txt

author: strawberry
author_rank: Super Contributor
timestamp: September 23, 2022, 06:51:57 pm
content: settling for13750/5000+750+10 trimmer
Tracor 900A VLF/LF Rx experience - Page 1
Forum section: electronics / general

author: wd5jfr
author_rank: Regular Contributor
timestamp: September 27, 2022, 10:36:30 pm
content: Just picked one up at a hamfest and never have seen or heard of one. Seems to be in pretty good physical condition so I'll have to try it out once I get my bench cleaned up and organized. It'll track 100 KHz or 1 MHz standard drift compared to whatever VLF/LF stations you can receive. Most of my stuff has 5 or 10 MHz standards, so I wonder if anyone has tried with 5 or 10.ThanksHankhere's link to manualhttps://www.glkinst.com/test-equipment/manuals/Tracor900A.pdf

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: September 28, 2022, 03:51:37 am
content: I've worked on a few of these and they work very well. unfortunately since the modulation change it wont work on WWVB!The main problem I found was bad switches! They need to work or you can't select the correct frequency!Cheers,Corby
Using the Wavetek/Fluke 9100 - Page 1
Forum section: electronics / general

author: jsolomonsc@gmail.com
author_rank: Contributor
timestamp: September 22, 2022, 01:37:19 am
content: I know this will sound like a really dumb question, but I am having a difficult time finding the answer.I have just repaired a Wavetek 9100 and I am doing some functional checks before getting involved with calibration. I am using a 6.5 digit dmm (34461A) to verify the 2-wire and 4 wire ohms function. 2-wire is fine. 4-wire is being challenging. I think it's a hook-up issue. there is no info in the manual. It does not seem to be the same as if I was using a 5500 or a 5520.When I look at a calibration procedure for the 9100 and they hook to a 8.5 dig dmm, they short the source and sense leads at the DMM end which does not seem right.but on the 6.5 without the shorts, my readings are all over the place. burden current is within the range of the calibrators.Does anyone have experience is using the 9100 sourcing ohms in a 4-wire mode? (And yes, I did turn on 4-wire on the calibrator and meter)thank you in advance,

author: CalMachine
author_rank: Frequent Contributor
timestamp: September 22, 2022, 02:24:11 am
content: The 9100 is meant to calibrate handheld DMMs with only 1 set of inputs for resistance measurements. So if you're doing 4-wire ohms, you'll want to connect your 4 wire cable up to the 9100 as normal, but then short the hi-sense/hi-current together and lo-sense/low-currnet together at the dmm input, preferably with the sense going into the dmm first.

author: jsolomonsc@gmail.com
author_rank: Contributor
timestamp: September 23, 2022, 01:14:02 am
content: Thank you for responding. makes sense... no pun intended. That confirms what I was seeing. just was not sure if it was correct.so all functions are working and its ready for alignment if needed.
Biddle 72-432 Wheatstone Bridge - Page 1
Forum section: electronics / general

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: September 17, 2022, 02:04:38 pm
content: I purchased a Biddle 72-432 Wheatstone Bridge at a Hamfest for a few bucksI brought it home and it appears to be in nice condition.I measured the resistance box function with my calibrated HP 3456It appears to be very accurate. Has four position switches, so four numbers/places.Does anyone have any experience with this particular unit?Here is the manual:https://elektrotanya.com/biddle_72-430_72-432_portable_wheatstone_bridges_sm.pdf/download.html

author: trobbins
author_rank: Frequent Contributor
timestamp: September 20, 2022, 11:57:58 am
content: Like any vintage wheatstone bridge, you could enjoy using your HP3456 to see how close the tolerance is of the ratio arm resistors and even investigate whether the individual resistors could be tweaked to gain at least an order of magnitude in accuracy for that aspect, assuming the bridge has protected itself over the decades from stress and you can arrange a suitably constant current. Your meter is in cal so should be able to confirm the decade resistor values both for absolute setting and step comparisons.
HP 5265A DCV Plugin, cal results of that nixie :-) - Page 1
Forum section: electronics / general

author: Martin.M
author_rank: Frequent Contributor
timestamp: September 18, 2022, 10:15:48 am
content: HP counter 5245L with DCV Plugin 5265A, some hours warmed up, 23.4°C around.here ist the result of calibration at the Makerfaire Hannover, done by the friends of PTB.Voltage given by the 5700 of them.the very aged nixie is still doing a great job
Volt nuts - Page 1
Forum section: electronics / general

author: artag
author_rank: Super Contributor
timestamp: September 11, 2022, 01:20:06 am
content: What happened to the volt-nuts list ?Seems like it got lost in the reorganisation of febo.comDoes it still run ?

author: alm
author_rank: Super Contributor
timestamp: September 11, 2022, 07:21:58 am
content: Yes, though it only sees the occasional burst of activity. Last time was a month ago. See here for how to subscribe and archive:https://lists.febo.com/

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 11, 2022, 08:13:32 am
content: The link was changed.http://lists.febo.com/list/volt-nuts.lists.febo.com

author: artag
author_rank: Super Contributor
timestamp: September 11, 2022, 12:35:01 pm
content: Thanks, in fact it seems I'm still on the (rehomed) list .. I just hadn't seen the updates in the forest of other testgear lists I'm subscribed to !(I did check the archives but due to the address change they stopped in about 2018, hence my question).
HP5065A Rb Fq St. Upgraded A7 (AC Amplifier) and A15 (PSU & Regulator)  - Page 1
Forum section: electronics / general

author: Uky
author_rank: Regular Contributor
timestamp: September 14, 2022, 08:00:20 am
content: Greetings.Updated designs for the A7 (AC amplifier) and a slightly improved designfor the A15 (DC Regulator board) has been uploaded to KO4BB manuals site.The A7 is a "drop-in" replacement.The A15 requres replacing the transformer based AC/DC rectifier circuitrywith a switch-mode 24V supply (and additional filtering). And I recommend thatthe +20V output is (coarse) adjusted prior to inserting the board in the 5065.Cheers.
Fluke 720A New build photos - Page 1
Forum section: electronics / general

author: volvo_nut_v70
author_rank: Regular Contributor
timestamp: September 11, 2022, 03:00:48 am
content: These are some photos I took of a new Fluke 720A, as can be seen by the new Fluke logo and serial number style.They are on the XDEVS doc site so that people can download them at the original resolution.https://xdevs.com/doc/Fluke/720A/Late_new_production_img/

author: manganin
author_rank: Regular Contributor
timestamp: September 11, 2022, 06:57:53 am
content: Quote from: volvo_nut_v70 on September 11, 2022, 03:00:48 amI have also one of those "new" units. Nothing really changed, except the modern trimmers are lower quality. And the new style binding posts no longer have gold plating, which means more cleaning.Of course the price in the second hand market will be higher, but that is more psychology than technology.The only real improvement was the change from the brittle transparent switch extender/insulator shaft to the more durable black version. But I think that took place earlier in the "old logo" era.
Photos of HP 85052B VNA Calibration Kit Standards - Page 1
Forum section: electronics / general

author: matthuszagh
author_rank: Frequent Contributor
timestamp: September 08, 2022, 05:31:28 am
content: I recently purchased a used HP 85052B VNA cal kit. As part of my verification of this kit I took pictures of the mating surfaces under a microscope (after cleaning). I'm posting the pictures here since I think others might find these images interesting and possibly useful. My other reason for posting is that I'd be interested to hear other's thoughts on the condition (particularly of the female broadband load). I haven't posted pictures of the adapters, since that's not as interesting, but I took them if people want to see. I also unfortunately don't have pictures of the sliding loads since I couldn't find an easy way to accomplish this with my setup.First, for those unfamiliar with mechanical cal kits such as this, Keysight had some good info on inspecting (https://web.archive.org/web/20220521170318/https://na.support.keysight.com/pna/connectorcare/Inspection.htm) and cleaning (https://web.archive.org/web/20220521170317/https://na.support.keysight.com/pna/connectorcare/cleaning.htm). The manual (http://www.av.it.pt/Medidas/Data/Manuais%20&%20Tutoriais/Software/XilinX/Kirby_SMA_Kit/85033-SN0211/Test_Equipment_manuals/Agilent-85052B-3.5mm_18GHz_calibration_kit-printed-2011.pdf) also covers these topics in a useful way.Unlike most 3.5mm connectors, the female connectors are slotless. When inspecting these, it's important to ensure all of the fingers are in the right position and none are bent. Additional things to look for are that the center pins are straight and the mating planes are free of dirt (which can often be removed with careful cleaning) and deep scratches. Light scratches are normal from typical use.The first image is of the female broadband load and is the only questionable connector in my opinion. The dark specs on the signal return mating plane appear silvery when viewed on the microscope and can't (at least easily) be removed with compressed air or lint-free swab and IPA. Although they appear metallic, if I had to guess I'd say they were compressed dirt rather than metal, but I don't know. What do people think about this? Are these small defects acceptable? This connector (and all others) gauges fine.All of the other connectors appear fine to me according to the above-mentioned criteria.
Tool - Q[W] for an insulated Box in LTSpice - Page 1
Forum section: electronics / general

author: iMo
author_rank: Super Contributor
timestamp: September 05, 2022, 02:16:01 pm
content: Attached a simulation of the rate of heat transfer Q for an insulated box.It should produce the same results as the excel table I published some time back.There is a youtube link inside - that is a lecture this tool is based on.The inner sizes of the box (w,l,h) and the insulation thickness (d) are in meters.Provided as-is, use at your own risk..PS: there are two shape factors - for edges (0.54) and corners (0.15) - those have to be adjusted in case the the insulation thickness d is comparable with the w or l or h. There are books written on this topic thus feel free to investigate..
Accuracy Test - Page 1
Forum section: electronics / general

author: CalTeK
author_rank: Newbie
timestamp: September 01, 2022, 07:18:21 pm
content: Hello: I have a test problem!!! A digital voltmeter can display counts up to 1999999 (6 1/2 digits). The range is set to 1 volt and has an input of .724 DCV. With an accuracy specified as +/- (4 ppm rdg + 10 LSD), the accuracy is +/- ____ DCV.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 01, 2022, 10:02:47 pm
content: Hello,to calculate the error budget is quite easy.First, you have a 2V range, i.e. up to 1.999 999V display, and its resolution is 1µV.10 digits (LSD) are therefore 10µV.4ppm of a 724mV reading are 2.9µV, so the total error would be +/- 12.9µV. (I don't like the term 'accuracy')That is equivalent to about 18ppm error of you measurement.So what's your test problem, now?Frank

author: CalTeK
author_rank: Newbie
timestamp: September 02, 2022, 03:10:34 pm
content: Thank's Frank. That's what I got.

author: mendip_discovery
author_rank: Super Contributor
timestamp: September 02, 2022, 06:08:33 pm
content: If you want to take it a step further then you need to look at measurement uncertainty which takes into account more of the measurement errors and the uncertainty of the lab that calibrated your 6.5digit meter.A quick bash into my calculator and I get around 5 μV/V + 13 μV Measurement Uncertainty with a 95% where k=2. But that is using the imported UoM from the lab that did my 6.5digit meter.
ADR1001-AHZ spotted in Analog Devices wiki post - Page 1
Forum section: electronics / general

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: August 27, 2022, 12:12:08 am
content: https://wiki.analog.com/resources/eval/adr1001e-ebzI didn't find this, but a friend on Discord did. @TheServer201 if you see this, all credits go to you

author: jbb
author_rank: Super Contributor
timestamp: August 27, 2022, 12:16:39 pm
content: Thar she blows!Interesting that they’ve a) included a buffer opamp (or at least suggestively named pins) and b) gone for a surface mount package and c) included heater control?I guess once you’ve got an oven going for your zener and resistors it’s attractive to put the opamp in too. And I guess some trimming…It will be interesting to see how this falls into the stability / noise rankings. Will it be better than an ADR1399? Or an ADR1000 with good external components? How about an ADR1000 with great external components?

author: sahko123
author_rank: Frequent Contributor
timestamp: August 30, 2022, 10:27:12 am
content: Oh god just wait till you see the datasheet

author: jbb
author_rank: Super Contributor
timestamp: August 30, 2022, 12:24:11 pm
content: I hope you mean that in a good way :-)I can wait.
DE-5000 LCR component test fixture or stuff into blades? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: August 27, 2022, 02:17:57 am
content: So on the De-5000 you can stuff a leaded components into the sense blades if you want. Is this safe, or do you need some kind of adapter to not damage the contacts to use it as a component tester? It seems perfect but I don't know if its a good idea.

author: macboy
author_rank: Super Contributor
timestamp: August 27, 2022, 02:39:09 am
content: That's exactly what those sockets are there for. Make sure to do the open/short calibration.

author: coppercone2
author_rank: Super Contributor
timestamp: August 27, 2022, 03:00:15 am
content: Quote from: macboy on August 27, 2022, 02:39:09 amOk I thought it was only for the adapters, I was not sure if those contacts are designed for leads
Resolution (digits) vs accuracy (HP 4274A/4275A) - Page 1
Forum section: electronics / general

author: Nevada
author_rank: Contributor
timestamp: August 15, 2022, 04:54:43 pm
content: Hi,Is there any sense to use the HP 4274A/4275A LRC meter in "high-resolution" (5.5 digits) mode despite it is specc'd "only" to 0.2%? E.g. if the indicated value is 1.00000uF, then the error is +/-0.002uF, so the nominal value could be somewhere between 0.99800 - 1.00200uF. It seems to be it is more closer to a 3.5 digits precision than a 5.5 digits.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 15, 2022, 05:25:46 pm
content: The higher resolution could still be used for things like matching capacitor sets or seeing of capacitance changes with temperature or similar. With higher resolution it is quite common that meters have better resolution than accuracy. The ration from accuracy to resolution also gets better lower in the range, e.g. just before one can switch to the next smaller range.The resolution specs could be for the actual display resolution or a noise level to get 1 count of RMS noise for the relevant speed. The accuracy specs are in a way to essentially guaranty that the error is smaller. This usually mean an additional factor of 2 or 2.5 for actual scattering of the true value. So even of the accuray would be limited by the noise, the accuray specs would be some 2.5 times higher then the resolution number. So the resolution is kind of requited to be at least 2-2.5 times better.

author: alm
author_rank: Super Contributor
timestamp: August 15, 2022, 05:32:36 pm
content: That's very common: for example the venerable HPAK 34401A is 6.5 digits, so on its 1 A AC range it will have a resolution of 1 µA, but the uncertainty even within 24 hours after calibration is 0.1% of reading + 0.04% of range, so for a 1 A input the uncertainty would be 1.4 mA, or 1400 counts.You should distinguish precision, resolution and accuracy. Seeherefor a nice, graphical illustration of these concepts. The reason why resolution has value beyond accuracy is that often the linearity and noise floor is much better than the accuracy. So you may not be able to say if a particular cap is 0.998 µF or 1.002 µF, but you might be able to know that a cap that measures 0.9984 µF is larger than one that measures 0.9983 µF, despite not knowing the value of either cap accurately.

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 16, 2022, 06:23:15 pm
content: Also be aware stuff swaps resolution for speed. It's a trade off, not everyone wants to wait 5 seconds to get a reading.I have found some stuff goes for amazing resolution but the last few digits are just wasted as the unit wanders all over the place. Looks are the Keysight handheld dmm.
Difference between push-on and thread-on microwave connector gages - Page 1
Forum section: electronics / general

author: matthuszagh
author_rank: Frequent Contributor
timestamp: August 15, 2022, 08:41:22 pm
content: Some of Maury Microwave's gage kits are threaded whereas others are push-on (seehttps://www.maurymw.com/Precision/Connector_Gage_Kits.php). I assume the direct difference is obvious: the threaded ones have threads to screw onto the RF connector wheres the push-on ones don't. Some connectors have both varieties (3.5mm), but others just have gages of one variety (eg SMA only shows push-on).In what ways are threaded preferable to push-on or vice versa?

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 16, 2022, 06:14:10 pm
content: With threaded gauge and a decent torque spanner I would assume you to get better repeatability. I was messing with some 40 GHz VNA stuff today and they used a spanner to ensure all results were good.The push on stuff would be quicker and depending on skill you could get ok results. I would be concerned with your hands warming them up. Depending on the ranges you are measuring temperature from handling can have some interesting errors.Depending on cost then I would be tempted to get the ones with the cheapest indicators as the ones I see in the pictures are just copies of the mitutoyo units. Then I would buy the mitutoyo units as they can be had in 0.001mm resolution and possibly better accuracy (MPE). But that is the mechanical measurement nut in me.
Fluke 7001 Volt reference - Page 1
Forum section: electronics / general

author: Abdullah1404
author_rank: Newbie
timestamp: August 14, 2022, 07:21:10 am
content: Hello everyoneWe have received the device from customer and the device was in off mode, we just connected in our lab for 5 days to get suitable temperature, but still oven indicator working and the output of 10V was 7V.please advice me to solve this.

author: branadic
author_rank: Super Contributor
timestamp: August 14, 2022, 08:04:55 am
content: You can find reverse engineered schematics by user chekhov over here:https://www.eevblog.com/forum/metrology/(3300)-wavetek-7000-the-hidden-gemstone/msg3452674/#msg3452674Fluke 7001 is similar to Wavetek 7000 except for the DC/DC converter.-branadic-
Request for information - Ovenaire OSC 49-63B 10 Mhz oscillator (HP-0960-0541-1) - Page 1
Forum section: electronics / general

author: Erik L
author_rank: Contributor
timestamp: August 07, 2022, 10:09:49 am
content: Ovenaire OSC 49-63B 10 Mhz oscillator (HP-0960-0541-1)I have made some research on the internet for this oscillator but haven't found any data so farDoes anyone on this amazing forum possess any information?Looking first of all for the required power for the unit, eventually datasheet would be fantastic.Thanks!

author: Erik L
author_rank: Contributor
timestamp: August 07, 2022, 05:40:15 pm
content: Wallace Gasiewicz tipped me that this oscillator could have been used in the HP 8672A.I downloaded the user and service manual and found out the power supply for the oscillator.Needed to do a little reverse engineering to find out the use of each pins on it.Details in the attached picture, maybe it can help someone else.

author: grizewald
author_rank: Frequent Contributor
timestamp: August 08, 2022, 05:15:13 pm
content: I have a very similar Ovenaire OCXO, original HP part number 0960-0477, subsequently renumbered to 5063-0257.Ovenaire part number OSC49-61C.Possible, but unconfirmed specs:Ageing Rate +/- 5x10-8/week (after 72 hours warm-up)+/- 1x10-7/month (after 15 days warm-up)I used this OCXO for a 5334A to replace the awful TCXO that was originally fitted.As the 5334A has +15V available for the oven power, that's what I used to power it. It drew 333mA from cold for 17 minutes before dropping back to 220mA and then more slowly down to 163mA after 25 minutes. The oven monitor signal started at 12.7V when cold and dropped down to 5.9V once. It finally stabilised at 151mA after 45 minutes and 5.5V This was with the OCXO in free air, so it will most likely be lower inside a case.The oscillator wanted 12V which resulted in a rock solid 2.5V P-P 10MHz sine wave and consumed just 18mA. Using 5V for the oscillator power only sort of worked and gave a twitchy and low level output.In the picture below, pin 1 is on the left and the pins are as follows:1 - Oven ground2 - Oven power3 - Oven monitor4 - Oscillator power5 - Ground - connected to case6 - Ground
Ammeter shunt to burden voltage relation - Page 1
Forum section: electronics / general

author: brumbarchris
author_rank: Regular Contributor
timestamp: August 08, 2022, 02:05:03 pm
content: Hello all,I am looking at the attached table, extracted from the detailed specifications of the Fluke 8845A multimeter; and I cannot correlate the figures for the shunt resistance and burden voltage. Take the 10mA, 100mA and 400mA ranges, for instance. They all share the same 1Ohm shunt. At 100mA, the voltage drop would be just 0.1V, not 0.25V.I understand that this burden voltage would also include the voltage drop on fuse and contacts, but even then, I would expect that the burden voltage for 400mA is 4 times higher than the one for 100mA and it is not. It is just double.Why is it so?Regards,Cristian

author: bdunham7
author_rank: Super Contributor
timestamp: August 08, 2022, 02:29:11 pm
content: The resistance of the 440mA fuse that protects all of the lower ranges is more significant in series with the 1R shunt but almost negligible in series with the 100R. So the 10/100/400 ranges will actually be much more than 1R, the spec implies <2.5R total (shunt+fuse+wiring). Actual measurement that I just did gives me .021, 0.21 and 0.84V burden voltage on those three ranges at full scale. So the spec appears to be just wrong on the 400mA range and everything else makes sense.

author: brumbarchris
author_rank: Regular Contributor
timestamp: August 08, 2022, 03:08:33 pm
content: Understood, thank you for the reply!Cristian
Wavetek (aka Meterman) 2030 calibration instructions? - Page 1
Forum section: electronics / general

author: perdrix
author_rank: Frequent Contributor
timestamp: August 02, 2017, 02:20:43 pm
content: Have these by any chance escaped into the wild? Or does someone have a paper copy lurking that they could scan?ThanksDave

author: perdrix
author_rank: Frequent Contributor
timestamp: March 12, 2022, 01:29:02 pm
content: Ever hopeful that this information has been found ...D.

author: DLJ
author_rank: Contributor
timestamp: July 28, 2022, 02:40:20 pm
content: I wish!!I have a 2030 that would benefit from a little adjustment.I have failed to find a cal/service manual for several years.Good hunting.David

author: bdunham7
author_rank: Super Contributor
timestamp: July 28, 2022, 03:07:18 pm
content: Take the case apart and post a good photo of the circuit board, perhaps someone will have an idea. I had a different (current production) 20,000 count meter that I did this to and I found a trimmer pot. It dialed everything right back into spec.

author: dseyst
author_rank: Contributor
timestamp: July 29, 2022, 02:22:08 am
content: If you remove the circuit board from the case and look below the pushbutton assembly you will see five trimpots. The trimpot to the far right adjusts dc voltage. That's all I have determined so far. I have two 2030 multimeters and I think eventually I'm going to use one as a control and the other to experiment on but as of now they both read very closely to each other so I'll probably leave them as is for now.
Agilent 6612C cannot avoid OUT OF RANGE error for current P2 cal - Page 1
Forum section: electronics / general

author: EE-digger
author_rank: Frequent Contributor
timestamp: July 20, 2022, 09:54:18 pm
content: A friend purchased this from BRL, with their cal, about 6 months ago and had not used it until now.The unit cals fine for voltage and low current.For CURRENT cal, I can display and set the data for the P1 parameter but get an "OUT OF RANGE" display when displaying the P2 parameter.I started cheating by cal at the front panel, thinking it must be fairly close, then switched to the rear to be safe.Has anyone run into this message and found the cause?

author: EE-digger
author_rank: Frequent Contributor
timestamp: July 22, 2022, 04:12:04 pm
content: I discovered that the B1A diagram is wrong. Load should be 1.1 ohm (not k) per youtubeBy using the current measure of the DMM, I got high current cal to work but now, low current cal shows the OUT OF RANGE when displaying a parameter P1.Any ideas? Is the firmware just flakey?

author: julian1
author_rank: Frequent Contributor
timestamp: July 23, 2022, 12:18:21 am
content: Is it possible to run unit, on the current range that fails cal and with a load? Then measure voltage drop on the current-sense resistor and determine if it makes sense, and if the current range switching works. This would help establish whether the fault is analog or digital/firmware. If analog, then just work forward in signal chain - check current at the ADC etc.

author: EE-digger
author_rank: Frequent Contributor
timestamp: July 24, 2022, 03:48:30 pm
content: Thanks for the suggestions and they would make good next steps. Unfortunately I can't do a deeper dive at this time.But, fixed it ! Actually, it was never broken.I had tried this previously but the OUT OF RANGE for high current threw me.So, high current must be cal'ed directly into the DMM current range, no B1A diagram nonsense.Then, the low current is cal'ed with the 1.1k resistor. The data entry must be in AMPS. If you enter 17.655 (the DMM mA display) you will get the OUT OF RANGE. It must be entered as .017655Once cal'ed, this is a nice little supply. My friend bought it for the low current measure capability for small radio and other work. I tried to convince him not to rely on the power supply but now this looks pretty good.
Replace binding posts on ESI SR104. - Page 1
Forum section: electronics / general

author: alligatorblues
author_rank: Regular Contributor
timestamp: July 16, 2022, 11:23:12 pm
content: I noticed on my SR104 I recently acquired that the binding posts have no banana sockets on top. So, I got some Pamona replacements, the best ones I could find besides the ones ETI actually uses on new units, which I was quoted at $79.00ea. But the guy said they're really good. Still, it was too much.But if I replace the binding posts, it will probably change the resistance value. When I have it calibrated, there would be no reliable relationship between the original calibration and the curreng one. Then I'd have no reliable drift figures. So, I thought maybe after the calibration I should do the job.Bt then the calibration would be off. So, I resigned myself to using the old ones with spade or pin teminals! What is anyone's opinion on replacing them?That standard requires 8 leads. Foour for the resistor and 4 for the thermistor. I connected just the resistor part, and it read really cl9se to 10K0. 9.9999901. So, I think it's OK. It didn't exactly have a warranty. I got it from a recent widow selling her deceased husband's stuff at a yard sale.She thought no one would want it, and she'd have to put it on the curb for trash collection, along with thousands of dollars of other equipment sitting there in a few of boxes. Some things only happen once. On Monday Night Football I saw a defensive player field a missed field goal and run it back 109 yards for a touchdown! Probably won't see that again either.

author: TiN
author_rank: Super Contributor
timestamp: July 17, 2022, 01:12:54 am
content: It would be a bad mistake to go mess with SR104 posts or internal wiring. Don't ruin most likely perfectly good reference standard.These resistors are not supposed to be used with bananas anyway, as no DMM can ever measure them accurately enough.

author: mendip_discovery
author_rank: Super Contributor
timestamp: July 17, 2022, 05:41:58 pm
content: What TiN says.Don't go adding banana stuff to it. Use it with low EMF stuff, spade connectors and all that.
Meatest Multifunction Calibrator - Page 1
Forum section: electronics / general

author: CrazyTiger
author_rank: Regular Contributor
timestamp: June 09, 2022, 09:13:40 am
content: Hi All,Yesterday I visited a calibration lab, and I found a strange looking Calibrator then the usual Fluke 57xxA/55xxA series, which really caught my eyes. The instrument was off, but I requested to turn on the unit.https://www.meatest.com/products-m143-portable-multifunction-calibrator-detail-3855?tabs=specificationsThe first observation I noticed was there was no actual button to turn on and off the unit, just the power supply on button at the back. The instrument had 5.5 digit display on voltage, could not check other functions, and they did not allow me to take picturesBut the did mention they just purchased the unit and its not yet put in as a calibration standard, and likely they will be using it to calibrate hand held multimeters. Honestly I have not seen this brand before anyone else have seen it?

author: alm
author_rank: Super Contributor
timestamp: June 09, 2022, 11:34:28 am
content: I've seen it mentionedhere, but that's the only time.

author: Ugur
author_rank: Regular Contributor
timestamp: June 10, 2022, 05:50:08 am
content: Hello,Yes, I know this brand, but at least I can say that it is not a product preferred by customers in Turkey.As you said, small calibration laboratories use this device only to calibrate handheld multimeters and clampmeters.

author: Pip
author_rank: Contributor
timestamp: July 14, 2022, 10:12:22 am
content: I first became aware of Meatest in 2017. They are the original equipment manufacturer of Fluke's 5320A and 5322A Electrical Safety Tester Calibrators and the Fluke 6003A Three Phase Calibrator (it looks very similar to the Meatest M133C).