Re: [volt-nuts] Bohnenberger electrometer
Hi Dave: Here's a free on line book "Magnetism and Electricity", 1877 https://books.google.com/books?id=y45PYAAJ&pg=PA169#v=onepage&q&f=false Chapter 6 Electroscopes and Electrometers starts on book page 74 (pdf pg 81) but . . Chapter 11 Voltaic, Dynamical or Current Electricity is where paragraph 214 Bohnenberger's Electroscope appears on book pg 169 (pdf 176). This is the chapter for the Voltaic Pile so that's probably why since it's a way to testing polarity. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Bohnenberger electrometer ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Anyone got a photo of a 3458A with "new volt" printed on it?
Hi Dave: I remember this. We already had an HP 3458 that was calibrated to the Old Volt and I ordered a new one that came with a "new volt" sticker. Tom, in the cal lab, connected them both to a voltage standard (maybe the Fluke 332) and the difference in their readings was very close to the deference in the definitions. Note the voltage source does not need to be accurate for this comparison, just stable. http://www.prc68.com/I/HP3458DVM.shtml http://www.prc68.com/I/Fluke332B.html PS Let me know if you find a photo of the sticker. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message IIRC, there are reports of 3458A's being sent to Agilent, and having a sticker to say the "new" standard volt was used - I assume the last time the volt was redefined. I was chatting to someone from my radio club in the pub last night, and somehow we got onto the definition of a volt. I'd like to try to research this, and perhaps give a talk at our radio club on it. I'd like to get a picture of a 3458A with such a sticker if I could. Dave Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT, UK. Registered in England and Wales, company number 08914892. http://www.kirkbymicrowave.co.uk/ Tel: 07910 441670 / +44 7910 441670 (0900 to 2100 GMT only please) ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Short term "standard" cell?
Hi Chris: I think it was my Heathkit VTVM that said to get a fresh AA battery and use it as a 1.52 Volt standard to calibrate the meter. An even better way was to use a Mercury coin cell since they were 1.35 volts and very stable. They were used for light meters and voltage references because of the very flat discharge curve. But when you are looking for many more digits of accuracy/precision then a battery may not be the best choice since pretty much everything will cause a variation. Maybe in order of importance: temperature, atmospheric pressure, humidity, impedance of measuring equipment, &Etc. There are a few low cost voltage standards available where the maker has an HP 3458. For example by Geller and Malone: http://www.prc68.com/I/MTE.shtml#DCVR The care and feeding of chemical standard cells is such a pain and they are inferior to the modern electronic standards so they have become obsolete. The label on my Eppley shows 5 digits (4 printed and the last hand written). Note since there's liquid involved there is also an "Up" direction. http://www.prc68.com/I/Eppley.html#Standard_Cell http://www.prc68.com/I/Fluke332B.html -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message In preparation of (hopefully!) Getting that fluke 332A running and sticker shock of what the 732A and similar references go for, I wonder about normal, every day alkaline or lithium batteries and their short term stability. Here's the half baked idea. A fresh, standard 1.5V, or 3V lithium, alkaline, or silver oxide button cell battery, or even an AA sized cell, measured by someone/some place with a known accurate precision meter. Invisioning 6 or so decimal places. Could that cell then be shipped, and used as a reference in another altitude? I haven't spent a ton of time looking, but haven't yet found anything on the web about stability of these types of batteries. Regards, Chris Sent from my SMRTphone ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Old v. New Volt?
Hi Frank: Thanks very much. I'm 99.999% sure the 332 is the instrument used. Not in the sense that it was accurate, but in the sense it could supply a voltage that stayed the same for a few minutes while it was read with the "old volt" 3458 then the "new volt" 3458. http://www.prc68.com/I/Fluke332B.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Brooke, I had the very same encounter in 1989/1990. I received the new 3458A in November 1989, and only 1 month later, on 1st January 1990, the New Volt (SI-1990) went effective. As my instrument came directly from the U.S., the difference in calibration was 9.264ppm, which the instrument now was reading high. You may read my whole volt-nuts story related to this SI - change here: http://www.eevblog.com/forum/metrology/1000-my-(hi)story-of-the-weston-cell-of-the-volt-and-of-being-a-volt-nuts/. The 332B might not have been your reference standard, as its uncertainty is 10ppm / 60days only. Maybe you had a 732A, or a bank of Weston cells in your lab, otherwise this change could not securely be observed by a solitary Fluke 33xB/D. best regards Frank --- Die Bundesliga hat begonnen! Alle Tore, alle Ergebnisse, alle News: Pocket Liga jetzt im AppStore oder Google Play Store herunterladen - kostenlos! ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Old v. New Volt?
Hi: When I was building automatic test systems we already had an HP 3458 in a system and when the second system was built the new 3458 had a front panel sticker (AFAICR it was green) with something about the "new volt". We checked them against a Fluke DC standard, not that the standard was that good, but so that we could see the difference in readings. The difference exactly matched the change in the definition. What difference would you see measuring say 10.0 Volts? Could the Fluke 332B be that instrument used then? This one looks very much like the standard we used. http://www.prc68.com/I/Fluke332B.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Initial Turn-On Fluke 332D?
Hi Mark: I hadn't thought of that, but have an ESR/Cap meter so will check it, Thanks. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message You will probably need to replace a lot of the electrolytic caps on the circuit board... ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Initial Turn-On Fluke 332D?
Hi: I just received a Fluke 332D from Fair Radio, but before I do anything is there some initial checks or a battery that needs attention? Just started reading the manual. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Practical power supply noise testing
Hi Poul When testing VCOs any noise on the control voltage causes a frequency change in the output which can be characterized. The HP/Agilent 4352 VCO tester contains a programmable DC supply with exceptionally low noise. Instead of headphones something like the HP 4395A which has a spectrum analyzer mode with a true RBW of 1 Hz to allow displaying root(Hz) noise levels (true I&Q detection rather than the old analog peak detection). http://www.prc68.com/I/4395A.shtml <http://www.prc68.com/I/4395A.shtml> AFAICR there were some HP app notes on measuring power supplies which may have included noise. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message In message <2656f010-8e12-4bad-b9ae-713cefee1...@febo.com>, John Ackermann N8UR writes: I have several supposedly low noise bench power supplies that I want to check out. They seem to work well but are quite old, so of course one wonders about the caps, etc. Can someone suggest a practical test regime to verify power supply DC noise performance? Preferably one that doesn't require building up custom low noise amps? Listen to them ? All the "hard" noise is in the audio-range, so a series capacitor a low-noise amp and a pair of headphones... ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Keithley 2001 vs HP 3457A multimeters / Any problems to watch out for on Keithley 2001? (Todd Micallef)
Hi Illya: When I try to view your web page the message is: Secure Connection Failed -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Aha! :) Hi David, First few sour points to make sure you got what to expect. * 520$USD is bit steep for 2001 from 90's you got, and VFD seem to be fairly faded according to auction pics. * It may be still have issues internally, even though showing reading does not reveal anything in first glance. 2001's are fairly capable DMMs and I personally dealt with no less than 7pcs of them over last years. Currently I still own four units of same age as your win (judge from S/N). While they are worse than 2002/3458 in terms of stability/noise, I would not trade my 2001's to fancy 3446X/34470 meters. Also 2001 support scan-card addons so you can easily expand DMM with scanner function, or even nanovolt-preamp if you dedicated enough. I'm working on nanovolt support with 2001, but that's long story. Some details with DIY card I covered here: https://xdevs.com/review/ema10/ To get you ready: 1). It's bit tricky to setup and need little bit of time to get familiar with, but otherwise on par with modern 34470/DMM7510 with bit worse resistance/current specs. No RS232, so bit more expenses to come for GPIB interfacing if you don't have that already. As Todd pointed out already to my repair article, some bits of info are linked there, as well as firmwares and documentation. Here's example test log with reading 1mV DC voltage with three meters : 2001,2002,3458. https://xdevs.com/datalog_tcomp/ 2001 also using almost exactly same ACV TrueRMS converter as 8.5 Model 2002, so that's good too if you into AC stuff. I also have thread on EEVBlog: http://www.eevblog.com/forum/testgear/restoration-glory-of-keithley-2001-dmm/ in case you missed it. 2) I never played with 3457A, but 2001 should offer better stability, less noise and more functionality in smaller package. I do take 2001 with me to remote locations sometimes to do some testing, thanks to it's relatively small size and weight. 4-5) You should update firmware to A08, which I hosted on links above, if you desire to have meter calibrated by accredited lab, such as Tektronix service center. Otherwise they might charge you for replacing simple PLCC ROM. Your digital board is older version, so you tied to A-version smaller firmwares w/o support of unobtanium nanovolt Keithley 1801 preamp. You will not loose existing calibration on firmware update. 6) This is my favorite part. Here's what you have to do: * Receive meter, take the cover off * Remove transformer, carefully remove plastic cover of analog board (top side) * Get the board out. * Replace ALL electrolytic capacitors on it. Follow my article for details. This is requirement, believe me. * If you already see gunk, liquid from caps - carefully clean board, restore any damaged traces/parts. If it leaked under ICs - you have to desolder them, clean in IPA thoroughly and solder back. * If your VFD too dim and you desire bright nice glow - you can buy Keithley 7001 switch with good screen from ebay (they can be found for 100-150$) and swap VFD. Not worth to bother asking Tek for new VFD, they sell front panel board only for ridiculous tag. * Replace caps on bottom digital board. * Install memory option if you like * You can deyellow plastic front panel with peroxide: https://xdevs.com/guide/plastic_bleach/ * Enjoy the meter. I sent one of 2001's for official cal here in Taiwan, it was 500$ for full cal with data. Cheaper than 8.5 DMMs but still bit pricey. To do user calibration you will need very stable 2V, 20V, 20kOhm and 1MOhm standards. Make sure you have meter running at least for a week before sending to cal, to get everything stable. P.S. there is no much point in 8.5th digit from 2001, as it's just down in noise. BR, Illya ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Anyone know how to make stable inductors?
Hi Dave: I'd classify this article more like pseudoscience than April's fool. To get an idea of the quality of the paper just check out the publisher. "The Chinese Publisher SCIRP (Scientific Research Publishing): A Publishing Empire Built on Junk Science" what I found by searching for the publication name on Beall’s List. This is a list of questionable, scholarly open-access publishers. These publishers are commonly used by "Medical" doctors to promote the "cure" they sell by referring to a paper in a "scholarly" journal. http://scholarlyoa.com/publishers/ I have the above link on my Faradic (Quack stuff) web page as the first entry in the Links paragraph: http://www.prc68.com/I/Faradic.shtml#L PS Some decades ago I spent over a year full time winding and testing coils on a Boonton 160 Q-meter. Even at that time the contemporary electronics college level text books did not cover inductors so bought the classics as used books (this was prior to internet so took some doing). http://www.prc68.com/I/Qmeters.html Using coils built with the knowledge from this testing I home-brewed a Crystal Radio with phenomenal performance. http://www.prc68.com/I/Xtal1800.shtml#BC1 Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Dr. David Kirkby (Kirkby Microwave Ltd) wrote: On 20 August 2015 at 02:38, Todd Micallef wrote: Here is a DIY guide to making some lab standards. It is detailed with some component values. http://nopr.niscair.res.in/bitstream/123456789/4848/1/JSIR%2065%286%29%20510-513.pdf If this was April the first, I would be convinced that paper was an April Fools Joke! I can't imagine how you can make high Q (low loss) inductors, by using a capacitor and two resistors. It just makes no sense to me, but I will read the maths later. The mere fact there is resistance makes me think it must be lossy, so low Q. Also the equations seems to come out with convenient numbers - R in Ohms, C in pF and H in Henries. But if the paper is real, it is very close to what I want, although it still leaves the position of finding stable capacitors. I thought inductors would be easier than capacitors, but maybe not. Dave ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Building a high resolution DAC
Hi: I haven't been following this thread but see it's about making a DAC with a lot of bits. While researching a Quantec GPS receiver I discovered a patent that for a 4 bit DAC to be used to drive a precision oscillator. http://www.prc68.com/I/Q5200.shtml#Patent It depends on using the carry out from an NCO that has a 48 bit input word. PS HP/Agilent has some instruments with very high quality programmable DC sources such as the 4352 VCO tester. These have very low noise but I forget how many bits. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Andreas Jahn wrote: Hello, its not only the plastic (epoxy) package. Its also the epoxy PCB which creates package stress to the die. And I do not believe that any "slots" make it significantly better. Thats why I use the AD586LQ; and soldering only one pin to the PCB. (the others with thin VERO-wire). With best regards Andreas Am 17.08.2015 um 18:46 schrieb Daniel Mendes: Look at LT6655 datasheet, page 14, about long term drift of MS8 versus LS8 package. If others refferences are as bad regarding moisture then i think this may be a problem at this level of accuracy. Daniel Em 17/08/2015 13:29, Andreas Jahn escreveu: Hello, I would rather use a reference with lower tempco than the LT1021. (typical 7ppm/K) E.g. (selected) AD586LQ or MAX6350. Or at least LT1236AILS8 with around 3ppm/K. The self heating alone gives around 3 deg C temperature difference. With best regards Andreas Am 17.08.2015 um 18:19 schrieb Attila Kinali: On Mon, 17 Aug 2015 15:38:37 + "Poul-Henning Kamp" wrote: You mean the AD7177-2? That seems to be quite hard to get by. I was thinking of the TI part intended for seismic applications. Hmm. The ADS1262 does indeed seem quite easily available. My goal was to stay below 30-40USD for the whole DAC if possible. But yes.. it might not be possible. I don't think it is. The necessary voltage reference will set you back almost that much... I thought about using the LT1021. I don't need the long term stability of the LTZ1000 and the LT1021 is available for less than 10USD. But from the discussion here, think i have to go back and see whether i really need such an high resolution or whether 20bit wouldnt be already enough. Then i could get away with a 20bit DAC like the DAC1220. Thanks Attila Kinali ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Oven thermal insulation
Hi: Look at cork. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Charles Steinmetz wrote: Chuck wrote: Bear in mind that the common ordinary styrofoam cup does just fine when containing boiling water. Sure, for the 4-5 minutes the water stays above 70C. But over 5-10 years 24/7/365 I once broke my office coffee cup and temporarily used a styrofoam cup as a replacement. I brewed tea in it once or twice a day, and in just a few weeks it had gone through significant dimensional changes (it was a little smaller and somewhat irregularly shaped). Best regards, Charles ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] The Art of Electronics
Hi Orin: Thanks very much. I've got a copy of T&S on order. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Orin Eman wrote: Try searching for the T&S V2 ISBN, 3540004297 on www.abebooks.com $40 for the International Edition from a somewhat reputable seller. Since this is an international list, I have no qualms about passing this on. Whether you can stand the almost transparent paper and smudgy ink is a different matter. Orin. On Sat, Apr 18, 2015 at 12:25 PM, Marv @ Home wrote: When AoE was released in 1980, the intended audience was electronics for a non-EE major. How this morphed into an engineering text shows how what is 'core' has changed. It had a friendly style, akin to having a instructor with you. AoE was best read in chapter sequence through the fundamentals, and higher chapters expect readers to know material from previous chapters without reference to it. On occasion it used concepts a jump forward but could be figured out by cross referencing its index. It was a semester course for us back in early 1980s. AoE v2 updated more in the digital domain with many corrected errata and typos from V1. I'd wait for V3 2nd printing or later, as typos from 1st printing are being reported as well as I read references to unpublished chapter "Xs" not in this printing. T&S is an excellent text, if you already know the material and just need a refresher. It gets to the point quickly. Only 2 T&S editions were translated to English; German has ?10+ editions. The only edition I ever looked at in print was v1, and it was $180+ in 1990s, compared to $50 for AoE new, or $20+ used. T&S used in the USA is harder to find, and few V1 I've seen sell near $100+. Student or someone with a cursory interest, cost, writing style and similar breadth could be a tie breaker, AoE V3 sells for ~$100 delivered, and V2 $20-30 used. T&S V2 from 2008 is ~$US260 delivered. At 04:33 AM 4/17/2015, Attila Kinali wrote: On Fri, 17 Apr 2015 08:24:38 + "Poul-Henning Kamp" wrote: How does it compare to the gold standard of the Tietze&Schenk? No idea. If you know a bit of german, get yourself a copy of it. You will love the in-depth explanations of the various electronics compontents. Also you can use it to knock out any burglar, should the need arise ;-) You have to remember that not everybody here are professional electronics people, I'm a software person who knows enough electronics to be useful without being dangerous, and I've certainly learned a lot from AOE3 over breakfast this past week. True that. The AoE gives at least a nice overview of quite a few electronics techniques. And probably not the worst thing you can start with, when you are new to electronics. That said, I kind of miss the amateur radio/electronics literature that was so abundant in the 80s. They really did a good job of introducing various circuits and how successfully build them if you don't have any professional equipment. Attila Kinali ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Checking an LCR meter
Hi Dave: The 4-terminal pair measurement method used on many of the HP (and other) LCR meters and impedance analyzers is much more accurate over many many decades of impedance value than network analyzers which are only accurate near 50 Ohms. This is explained in the impedance measurement handbook. In my mind the key to an accurate measurement is to know which of a number of impedance measurement techniques to use. The Z hdbk has contour maps showing the effect of frequency, impedance and accuracy for a number of different measurement techniques. http://www.prc68.com/I/Z.shtml#KeyDocs The other key idea is that LCR measurements are done on components without connectors and so there's the handling of the fixture parasitics. This is far from trivial. Again the Impedance Measurement Handbook is essential and the Measurement Accessories Selection Guide is very handy. And finally by making impedance measurements over a broad frequency range you can fit a model to the data instead of utilizing the simple series or parallel 2 component model that's standard in an LCR meter. This simple model may be fine for a lot of applications, but is not good for more complex cases. For example the model for a crystal resonator that's built into the E4915, E4916 & E5100 is based on an S21 measurement and the use of a low-Z PI test fixture. What all these instruments have in common is frequency sweep and DSP IF processing. See my Crystal Equivalent Circuit web page for an example of a Z-transform (Z:T in upper left of screen shots) measurement. http://www.prc68.com/I/Xec.shtml Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Dr. David Kirkby (Kirkby Microwave Ltd) wrote: I have bought an HP 4284A precision LCR meter. This is an old model with a basic accuracy of 0.05% and covers 20 Hz to 1 MHz. Converting the specifications into determining the uncertainty of a measurement is nontrivial, but I think it reasonable to assume the uncertainty will always be >0.05%. Surprisingly the current precision LCR meter from Kesight, the E4980A (20 Hz to 2 MHz) offers the same basic accuracy. So while fairly old, the 4284A doesn't seem to be miles behind the current crop LCR meters from the top manufacturers. The recommended calibration period on the 4284A is 6 months, which would get rather expensive - on the current E4980A the calibration period is a more respectable 12 months. I am looking for suggestions on how I can get "reasonable" confidence in the instrument at "reasonable" cost, without returning it to Keysight every 6 months. I have a 3457A DVM, but mot much else in the way of precision low frequency equipment. It has 4 BNC connectors for Kelvin probes. I suspect that getting precision resistors and keeping them for a house standard might be worthwhile, but are looking for suggestions on the best approach. I will send it to Keysight once when it arrives to ensure that there are no faults on it, but I don't currently feel I can justify getting it calibrated every 6 months. Maybe I can make some stable "standards", then measure them soon after the LCR meter calibrated been calibrated and periodically measure their values. Any suggestions about how to approach that? Dave ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] HP419A Meter Pegged to Right
Hi: My second oscilloscope was a new Tek 515 which I got for the student price and picked up from the Tek sales office on San Antonio Rd in Palo Alto. On the tour they showed me the washing booth where they used a water soap solution to spray wash the complete scope. There were no parts in the design that would absorb water. When washing semiconductor wafers after the DI water rinse they used an alcohol rinse then a compressed clean air blow off. The alcohol sucks up the water and what small amount that's left after the air evaporates quickly. Mail_Attachment -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html David C. Partridge wrote: And should you be prepared to remove the pots, you could run it through the dishwasher ... (if it works for Bob Pease, it works for me too). Regards, David Partridge -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of ed breya Sent: 11 November 2014 07:44 To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] HP419A Meter Pegged to Right If you're talking about washing the board only, I'd say go for it. : : Ed At 07:28 PM 11/10/2014, you wrote: I'm trying to bring an HP419A back to life. : : Any votes for a water wash? Any better ideas? ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Finally got around to modifying my Fluke 845ab with LED's
Hi Chuck: Is there something special about the GR strobe tube that prevents you from using a more modern strobe tube? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Chuck Harris wrote: Hi Mark, I have an itty bitty white led, probably called a T-1 size, and it glows dimly for a long time after you shut it down. They all pretty well have to. I think what you are seeing with your analyzer is the blue/UV component that drives the phosphor element. It will run just as fast as any old style LED. I also think that the blue/UV component, which is very bright, is what is driving Dallas's chopper. But enough on that. I wasn't trying to criticize, just make mention of something I noticed in my own work. Where I got to thinking of this is when I burned out the strobe tube in my G-R strobotach. Replacement tubes were in the $300 range, so I knew that would never happen, so I was thinking of making a solid state replacement using a handful of those wonderful little white LED's. They would certainly be bright enough, but I'm pretty sure the phosphor hang would make them unsuitable for stopping motion... your eye would see a blur instead of the razor sharp image you get with the strobe tube. -Chuck Harris Mark Sims wrote: I would probably use green or yellow LEDs, but the white ones should not be a problem. I built an LED analyzer/integrating sphere and one of the features is a circuit that optically measures the LED driver PWM frequency. It can also detect the minute variance in LED intensity from an LED driven by a 950 kHz boost converter. It also had no problems with a white LED driven at 4 MHz from a signal generator. You see the long persistence phosphors mainly in large lighting LEDs and not in small indicator LEDs. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Finally got around to modifying my Fluke 845ab with LED's
Hi Mark: Do you have a web page on the LED analyzer/integrating sphere? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mark Sims wrote: I would probably use green or yellow LEDs, but the white ones should not be a problem. I built an LED analyzer/integrating sphere and one of the features is a circuit that optically measures the LED driver PWM frequency. It can also detect the minute variance in LED intensity from an LED driven by a 950 kHz boost converter. It also had no problems with a white LED driven at 4 MHz from a signal generator. You see the long persistence phosphors mainly in large lighting LEDs and not in small indicator LEDs. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Building a box to measure DC resistance of multiple RF loads.
Hi David: I would think to get the most accurate result you should use Kelvin connections where the V & I leads for each terminal contacted the load under test. So, rather than using a mating connector you would use something like pogo probes where two probes would contact the ground and two would contact the center terminal. For a nominal 50 Ohm value Dc measurements will be OK, but I found for measuring very low resistance values AC must be used. I've measured the real and imaginary components of various things with the HP 4395A 0 to 500 MHz combo box which is essentially a measurement near DC. Here's a page showing the the Zo of a transmission line is not constant across all frequencies. Scroll down for some plots showing what amounts to the DC resistance. http://www.prc68.com/I/Zo.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Dr. David Kirkby (Kirkby Microwave Ltd) wrote: I am looking to measure as accurately as possible the DC resistance of a number of types of RF loads - all around 50 Ohms. Types of interest include SMA, 3.5 mm, N, APC7, 7-16 & BNC. I want to see if the difference between the actual resistance at DC and 50 Ohms correlates with the performance at RF as measured on a vector network analyzer. I want to do both sexes, with the exception of the APC7. I would expect RF performance to correlate well at low frequencies, but as the frequency is increased I would expect it not to correlate. I am looking for advice on the best way to do this. I have a HP 3457A (6.5 digit DVM with 4-wire resistance capability), but will consider purchasing a meter designed for low resistance measurements which I believe uses AC to avoid thermal EMF issues. But if possible I would rather use the 3457A. I was thinking of a plastic box with the RF connectors & 4 banana plugs. I suspect running the sense and drive wires back to the banana plugs would work. No signicant current would flow into the unterminated connectors as they would have just the dielectric. Ideally I would like to measure just the load and contact resistance and not the resistance of the plug or socket I connect it to. That might be next to impossible. Can anyone offer any recommendations of how to wire it up, type of connector (e.g. banana plug or similar) PS I once see someone selling a dummy load on eBay with an SO 239 socket and 47 Ohm wire wound resistor! Apparently the inductance made it 50 Ohms. Dave ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Eppley standard cell catalog ?
Hi Pete: I don't have info on that particular number there is some info about their patents at: http://www.prc68.com/I/Eppley.html PS their standard cell bulletin has two and three digit catalog numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Pete Lancashire wrote: Looking for spec's on model 705489 -pete ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] current-nut question .. total waste of ones time type question
Hi Pete: I did this may decades ago. 1) Do not use clamp on current probes, they have very poor accuracy at low currents. 2) Rather than using a current monitor on each circuit just use two current sensors, one on each input leg. 3) Current transformers MUST be terminated with some load resistance, i.e. they transform an input current into an output current which gets changed to an output voltage by the load resistor. I put the load resistor close to the current transformer so that a break in the long cable would not cause a problem. 4) I plotted current use on an 8.5 x 11 paper in landscape mode. Each trace was offset from the prior trace by about 1/4". At night when not much is happening you just have a bunch of straight lines, except for the frig which has a regular cycle. But if someone gets up at night you can tell. Smart meters can provide data every 15 minutes, if they are in a network. My smart meter gets read manually so no data. http://www.prc68.com/I/SmartMeters.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Pete Lancashire wrote: Next spring I'm going be rewiring my house. And for 'fun' I want to drop a couple current sensors on the input side of the main panel. Being a beginner 'nut', I'm looking for more accuracy then needed. Voltage, Frequency, waveform will be taken care of later, but accurate current has be a bit flustered. I've been reading up on CT's Iron core and Ferrite, and on Rogowski coils. And the many new IC's on the market that take care of a lot of things. Has someone done this before ? And if so any experiences to share ? -pete ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 34401A Why 10M ohm default i/p resistance?
Hi John: Because when measuring a source with a high resistance you get a different answer. Some W.W.II electronics specified 1 kOhm/Volt meters and if you used a VTVM you got the wrong results. If a test procedure specifies a 10MOhm input meter and you use a higher input Z then you may get wrong results. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html John Phillips wrote: so why do you care what the input is as long as you know what it is and how to make it do what you want? On Thu, Apr 10, 2014 at 1:16 PM, Brent Gordon wrote: Pure conjecture: So that the reading on the 34401A matches that on a $20 DVM. Or stated differently: So that the input impedance is the same as other DVMs. Brent On 4/10/2014 8:23 AM, Tony wrote: There is no suggestion in the specifications for the 34401A that the accuracy suffers by selecting 10G ohm input resistance on the .1 to 10V range so why would they make 10M ohm the default? I can think of very few cases where having the 10M ohm i/p resistor switched in is better for accuracy than not. On the other hand 10M is sufficiently low to produce significant errors on a 6 1/2 digit DVM for sources with resistances as low as 10 ohms. Measuring 1V divided by a 100k/100k ohm divider for example causes a .5% error - 502.488mV instead of 500.000mV. That might not be a problem but I wouldn't be surprised if this catches a lot of people out (including me) when not pausing to do the mental arithmetic to estimate the error. It's just too easy to be seduced by all those digits into thinking you've made an accurate measurement even though you discarded those last three digits. And if it's not a problem then you probably don't need an expensive 6 1/2 digit meter in the first place. It's a small point I agree but it can get irritating to have to keep going into the measurement menus to change it when the meter is turned on when measuring high impedance sources (e.g. capacitor leakage testing). It can't be to improve i/p protection as 10M is too high to make any significant difference to ESD and in any case there is plenty of other over-voltage protection. OK. it provides a path for the DC amplifier's input bias current, specified to be < 30pA at 25 degrees C, but I imagine that varies significantly from one meter to the next, and with temperature, so not useful for nulling out that error. So why would they do this? ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] 34401A Why 10M ohm default i/p resistance?
Hi Tony: Fluke makes some DDMs that have what they call V-Check where they put a 1,000 Ohm resistor across the voltage input. When testing lawn sprinkler valves if you measure the voltage across the valve with a Hi-Z voltmeter it looks normal, but using the V-Check range on the DMM shows the voltage to be almost zero. http://www.prc68.com/I/DMM.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Tony wrote: There is no suggestion in the specifications for the 34401A that the accuracy suffers by selecting 10G ohm input resistance on the .1 to 10V range so why would they make 10M ohm the default? I can think of very few cases where having the 10M ohm i/p resistor switched in is better for accuracy than not. On the other hand 10M is sufficiently low to produce significant errors on a 6 1/2 digit DVM for sources with resistances as low as 10 ohms. Measuring 1V divided by a 100k/100k ohm divider for example causes a .5% error - 502.488mV instead of 500.000mV. That might not be a problem but I wouldn't be surprised if this catches a lot of people out (including me) when not pausing to do the mental arithmetic to estimate the error. It's just too easy to be seduced by all those digits into thinking you've made an accurate measurement even though you discarded those last three digits. And if it's not a problem then you probably don't need an expensive 6 1/2 digit meter in the first place. It's a small point I agree but it can get irritating to have to keep going into the measurement menus to change it when the meter is turned on when measuring high impedance sources (e.g. capacitor leakage testing). It can't be to improve i/p protection as 10M is too high to make any significant difference to ESD and in any case there is plenty of other over-voltage protection. OK. it provides a path for the DC amplifier's input bias current, specified to be < 30pA at 25 degrees C, but I imagine that varies significantly from one meter to the next, and with temperature, so not useful for nulling out that error. So why would they do this? Could it be psychological? By limiting the drift caused by the i/p bias current to 300uV max when the meter is left unconnected? A voltmeter with a rapidly drifting reading (several mV/s) when not connected to anything is a bit disconcerting and would probably lead to complaints that the meter is obviously faulty to users who are used to DVMs which read 0V when open circuit - because they have i/p resistance << 10G ohms and don't have the resolution to show the offset voltage caused by the i/p bias current. Personally I'd have though that the default should be the other way round - especially given that there is no indication on the front panel or display as to which i/p resistance is currently selected. Any thoughts? What do other meters do? Tony H ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Eppley 811381 standard cell
Hi: I got an Eppley 811381 standard cell and am looking for info on how to use it. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Keithley SourceMeters
Hi John: A SourceMeter is just the combination of a Voltage/Current source and a meter that can measure current/voltage. More like the HP 4141 or 4142 than the 4140. The tricky part of using them to measure semiconductors is setting the compliance for the sources so that you don't blow out the semi. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Clarke4Congress.html J. Forster wrote: At a quick glance, the Keithley box looks like an HP 4140 or an earlier PAR C-V plotter. These things characterize PN junctions by integrating the current for a series of voltage steps. The integral of the current.dt is the charge, so they can work back and figure the capacitance. They effectively measure the capacitance of the SCL as a function of voltage. Of course the SCL is a function of the reverse bias on t6he junction. -John == Hello Fred, Regarding your question on Keithley SourceMeters: Short question, keithley makes source meters, They are in the micromeasurements handbook but I can not really place this. It sounds like a sort of IV meter, or coulomb meter but for DC. Not planning to buy one, just curious. They are basically precision power supplies with precision measurement capabilities. They are frequently used to test VCSELs (a type of laser diode) and LEDs. Here is part of the description from <http://www.keithley.com/products/dcac/currentvoltage/gpmp?mn=2400>: All SourceMeter models provide precision voltage and current sourcing as well as measurement capabilities. Each SourceMeter instrument is both a highly stable DC power source and a true instrument-grade 6½-digit multimeter. Brent ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Impedance bridge information
Hi Fred: Here's my page on transmission line Zo and how it's not a constant impedance: http://www.prc68.com/I/Zo.shtml I've added a list of impedance equipment on the Impedance web page: http://www.prc68.com/I/Z.shtml#Rel I've used a number of the Keithley DC boxes for automated testing of semiconductors. http://www.prc68.com/I/RASS_PP.html#D http://www.prc68.com/I/RASS_PP.html#TD They are great where you need a current source in the nano or femto amp range or higher. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Clarke4Congress.html Fred Schneider wrote: Thanks for the info, the HP impedance measurement handbook is a bit my bible so I know it. About analysers, i know a modern impedance analyser, be it a vna, IV, or just a LCR meter can be more accurate and has more possibilities. I have two digital vna's ( DG8SAQ VNWA) one that has the RF-IV test head designed by Paul and an analog one from HP. The latter I yesterday used to make RF-IV measurements as an experiment. A tek CT currentprobe from splitter to reference and the other output via a shunt fixture to the test port. The result was above wat I expected, a nice impedance curve that has a resolution of 40 dB under 1 ohm. I am most time busy doing network analysing, component research, most of them involve capacitors and parasitic behaviour of components. And playing with calibrators. But I teached my self everything and i have no math education so I always avoided that ( i have discalculus too) but I like it a lot and the lat time I try to get back to the basics for deeper understanding about what I am meaduring and for most practice and learn some math. The result is new ( that is for me) ways to measure things. I ( re ?)invented a CF converter, build snd designed a IV-meter like fF meter, did coulomb and C ( under 10pF) measurements with a O plugin in an old Tek 547 ( after that i found out it was, in a different form, described in the manual). Did tek-130 style C measements like described by Terman. Measured capacitanceusing DC, tryed about 10 ways to measure ESR, recently tried to measure the parasitics of 10 m bare wire. Things like inductance, resistance, skineffect, Q, capacitance ect. Very intresting, the meaurements worked, grapical it made sense and gave an idea, but the math was to complex for me to extract it to numbers, gave the data ( thoug! hstone files) and graphs to a friend who is a math , RF engineer and RF guru but he had to admit it was even to complex for him. He could probably do it but it would take to much time. I could not anlyse the data my self. This is pure hobby, I do not even have an electronic education. I have a marconi TF1313A, 0,1% bridge and a HP ( the same, like the damaged one you have) I builded a simpke complex measurement bridge based on the arrl antenna handbook. Also made a poor mans wobbulator based on a noise source, external signal generator and audio SA software ( involved mixing so it could be used for the whole HF band) But it would be great to have an old bridge like the GR ones. With lots of knobs and after that calculate from there, to the corrections ect. Mostly to measure capacitove stuff. I'm offered a GR1620 from a list member that I will buy, i read the manual and I allready love it. With the info gathered I also would like to have a passive RF type bridge. I know I can easy use a vna but I like to measure the basics and try to extract the other parametrs from there as a learning experience. I am now doing some 3 voltmeter experiments. It is nice to compare results from this experiments to my vna. Some times I'm way of but it feels good if it worked out well. Like meauring capacitance and esr on a curvtracer, that was fun. Or the RI-IV meaurement of a cap. After that I had calculated esr capacitance and esl from that I did a simulation and that gave the same SRF. That gives me a kick. So to be short ( very difficult for me ;-) ) , i do not have a need for a frequency or so, i adjust/ make up my experiments around an instrument. Thanks to the answers from you and the others and your link i now know were to look for and use the right search terms. First wait for answer from the seller of the GR about transport and hopr we find a way abd then play with that nice instrument and then look for a RF admitance/impedance bridge. Short question, keithley makes source meters, They are in the micromeasurements handbook but I can not really place this. It sounds like a sort of IV meter, or coulomb meter but for DC. Not planning to buy one, just curious. Thanks, Fred PA4TIM Op 25 mei 2012 om 22:41 heeft Brooke Clarke het volgende geschreven: Hi Fred: In HP speak "meters" have numerical readouts and "analyzers" have graphical readouts. So the 4-terminal pair LCR meters are good, but the 4-terminal pair LCR analyzers are better. You can substitute
