Re: [volt-nuts] Buying HP-3458A

2014-07-06 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 6 Jul 2014 07:12, John Phillips john.philli...@gmail.com wrote: ​They do really offer that service as​ long as you send them a complete meter... No missing parts. Well they will take a few missing screws and such. There is also the possibility someone has tried repairing it, but done so

[volt-nuts] Building a box to measure DC resistance of multiple RF loads.

2014-08-16 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
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

Re: [volt-nuts] The averaging reference

2014-12-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 18 Dec 2014 19:06, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 5492f59e.8060...@free.fr, Joel Setton writes: In my search for the Perfect Volt, I'm thinking about building a reference voltage generator which would average the voltages generated If you want to do it

Re: [volt-nuts] The averaging reference

2014-12-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 19 Dec 2014 19:30, Jan Fredriksson j...@41hz.com wrote: It's no coincidence that virtually all 8.5 digit DMMs use the LTZ1000. It's in a class of it's own. What do the 8.5 digit meters use if they don't use the LTZ1000? Dave. ___ volt-nuts

Re: [volt-nuts] The averaging reference

2014-12-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 Dec 2014 21:18, Joel Setton set...@free.fr wrote: Jan, Thanks for a good summary f the pros/cons. Of course the LTZ1000 is much closer to the current state of the art, but the REF102 is far easier to use and to calibrate. I'm definitely not shooting for sub-ppm performance, if I can

[volt-nuts] Checking an LCR meter

2015-02-06 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
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%.

Re: [volt-nuts] 3458A reference boards on ebay

2015-01-27 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 27 January 2015 at 09:16, Orin Eman orin.e...@gmail.com wrote: There is a seller letting a slow trickle of them out there... they seem to be going for about $165. The current batch of two is around $100, but will probably be bid up. I just received one that I won. Seems to be working

Re: [volt-nuts] plastic caps on 3458A reference board

2015-01-28 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 28 January 2015 at 18:56, Charles Steinmetz csteinm...@yandex.com wrote: The problem is that an LTZ1000 (or LM399) runs hot enough that most plastics you find lying around won't stand up to it for very long (some of them melt almost immediately when you power it up). This is true even of

Re: [volt-nuts] Design Spark PCB Design Package

2015-01-05 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 5 Jan 2015 15:36, Randy Evans randyevans2...@gmail.com wrote: This is indirectly pertinent to the group since I am designing a PCB for the HP-419A and Fluke 845A modifications. Does anyone have any experience/comments on the Design Spark PCB design package? Is is a viable package for

Re: [volt-nuts] 3458A reference boards on ebay

2015-01-29 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 27 Jan 2015 09:47, Orin Eman orin.e...@gmail.com wrote: There is a seller letting a slow trickle of them out there... they seem to be going for about $165. The current batch of two is around $100, but will probably be bid up. I am puzzled why there are so many reference boards that are

Re: [volt-nuts] 3458A reference boards on ebay

2015-01-30 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 30 January 2015 at 12:25, Will willvo...@gmail.com wrote: The boards are factory rejects. I doubt all boards on eBay are in this category. Some are probably quite genuine, some may be rejects, and it would never surprise me if some are counterfeit. The problem is, I have no idea what ones are

[volt-nuts] Keysight seminar of possible interest to those in the UK

2015-05-13 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
This might interest those with an interest in metrology in the UK. It is run by Keysight on the 16th and 18th June http://www.keysight.com/main/eventDetail.jspx?cc=USlc=engckey=2553856nid=-33166.920244.08id=2553856cmpid=1-6830540895 The annoying this is Keysight are running something else that

[volt-nuts] Seminar: Fundamentals of Low Current and Ultra-High Resistance Measurement

2015-04-11 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
Google that and you should find a seminar sponsored by Keysight, scheduled for Tuesday, April 14, 2015 1:00pm ET / 10:00am PT (I'll convert to GMT later) Trouble is, it is streamed in a Windows format. Dr. David Kirkby Ph.D CEng MIET Kirkby Microwave Ltd Registered office: Stokes Hall Lodge,

[volt-nuts] Stabilising resistors

2015-08-16 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I have bought some resistors of 0.1, 1.0, 10, 100, 1k, 10k 100k Ohms. These are in little boxes with 4 BNC connectors spaced 22 mm apart. This sort of thing http://m.ebay.co.uk/itm/231460477406 although I paid a *lot* less. They are designed for use verifying the performance of LCR meters. I

[volt-nuts] Anyone know how to make stable inductors?

2015-08-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I was looking to make some inductors that I can use as a sanity check for my HP 4284A LCR meter. I don't too much care what their values are, but I want them to be stable with time. Any suggestions about the best way to make or buy them? I'd like values in the range of 1 nH to 100 mH. The LCR

Re: [volt-nuts] Anyone know how to make stable inductors?

2015-08-21 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 August 2015 at 02:38, Todd Micallef tmical...@gmail.com 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 OK, I tried this. I was hoping to use a

Re: [volt-nuts] Anyone know how to make stable inductors?

2015-08-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 August 2015 at 02:38, Todd Micallef tmical...@gmail.com 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

[volt-nuts] LCR meter calibration certificate

2015-08-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I just got my LCR meter back from Keysight today. For anyone interested in looking at the cal certificate, which includes the uncertainties, a copy may be found here,

Re: [volt-nuts] Anyone know how to make stable inductors?

2015-08-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 August 2015 at 19:11, Brooke Clarke bro...@pacific.net wrote: 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. Yes, the publisher does seem dubious. If Wikipedia is to be believed,

Re: [volt-nuts] Anyone know how to make stable inductors?

2015-09-01 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
> external influences as possible. Of course, the same couild be said of > any > > physical or electrical standard. > > > > Cheers, > > Dave M > > > > > > > > > > Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > > > >> I was look

[volt-nuts] Could you fall an HP 4-wire LCR meter into thinking you have a negative resistor?

2015-09-01 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I just sent an email by mistake, failing to finish it before hitting "send". The recent discussion about creating inductor standards from a capacitor and two resistors got me thinking. I suspect if you connected up an HP (or similar) LCR meter in a way not intended, you could make it appear you

Re: [volt-nuts] Making a Reference IC

2015-09-14 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 13 Sep 2015 09:15, "M K" wrote: > There has been some of those references available second hand from ebay, mostly pulled, but some may be counterfeit, so look for sellers with pictures showing it as old.. Several sellers have more than 1, but with one photo, so you would

Re: [volt-nuts] Low-cost voltage reference questions

2015-11-29 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 Nov 2015 11:18, "Charles Steinmetz" wrote: > > I'm curious why you think the AD587/586 are better than other hermetically packaged references with better drift and noise specifications -- in particular, > > MAX6350MJA > AD588KQ > LTC6655CHLS8 > LTC6655BHLS8 >

Re: [volt-nuts] Low-cost voltage reference questions

2015-11-29 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 29 November 2015 at 10:53, Charles Steinmetz wrote: Dave wrote: > > As regards humidity, I wonder if an reasonable attempt at sealing a package >> combined with silica gel inside would give an internal humidity that keeps >> fairly stable. >> > > That is exactly what I

Re: [volt-nuts] LTZ1000 project build

2016-06-04 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 4 Jun 2016 20:44, "Poul-Henning Kamp" wrote: > > > In message <57527f8a.6070...@yandex.com>, Charles Steinmetz writes: > > >As I have mentioned before, for many years I have put precision circuits > >that may be sensitive to humidity into gasketed metal boxes with

Re: [volt-nuts] LTZ1000 project build

2016-05-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 May 2016 at 19:24, Russ Ramirez wrote: > A lot of great information Eric, thanks for sharing the link. > > Due to my ignorance in general on the subject of Metrology, I have the > following question for the list. > > If one built a project with the LTZ1000, like the

Re: [volt-nuts] Keithley 2001 - do you need to open it to calibrate it?

2016-06-26 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 26 June 2016 at 20:46, Todd Micallef wrote: > David, > > I have found that many sellers like to remove any calibration stickers or > tamper evident stickers. Not sure why they do that as a sticker does not > mean the item is calibrated. > The sticker on the front has

Re: [volt-nuts] Thermal EMF of common solder

2016-06-26 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 26 June 2016 at 15:12, Andrea Baldoni wrote: > Hello All. > > I measured the thermal EMF of two common solder, the lead free > Sn96.5/Ag3/Cu0.5 and the old Sn60/Pb40. > Please excuse my ignorance, but how do you mean the thermal EMF of solder? Do you not need another

[volt-nuts] Keithley 2001 - do you need to open it to calibrate it?

2016-06-26 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I got the 2001 that I ordered yesterday. There are a few things that make me feel uneasy about it, so I will probably return it. The calibration seal is missing off the front, which is obvious from the eBay photo, but also one at the bottom which looks as though one needs to open in order to get

Re: [volt-nuts] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?

2016-01-31 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 January 2016 at 11:12, Dr. David Kirkby (Kirkby Microwave Ltd) < drkir...@kirkbymicrowave.co.uk> wrote: > As noted in another thread, I want to replace a battery in a 3457A that > has not been replaced in at least 11 years. The instrument has not been > calibrated in t

[volt-nuts] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
As noted in another thread, I want to replace a battery in a 3457A that has not been replaced in at least 11 years. The instrument has not been calibrated in that time either. At the time it was purchased from a dealer, I was told it was within specification, but if I wanted it calibrated I would

Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 January 2016 at 15:23, Andrea Baldoni <erm191...@ermione.com> wrote: > On Sun, Jan 24, 2016 at 07:54:34PM +0000, Dr. David Kirkby (Kirkby > Microwave Ltd) wrote: > > > I've got a HP 3457A 6.5 digit multimeter - S/N 2703A04579. It's working > > fine, but

Re: [volt-nuts] 3457A - should I preserve SRAM contents, or purposely corrupt them by removing power?

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 January 2016 at 15:40, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > In message < > canx10halwjxt+8ev8lywdqy9eez+anawihgqeyrzntsy80v...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >I'm wondering if I wou

Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 Jan 2016 03:51, "Tom Miller" wrote: > > Looking through the service manual I don't see a connection from the battery to the NVRAM. I am sure I measured battery voltage on pin28 so I suspect a schematic error. Can someone that has one open verify that? My 3457 is in

[volt-nuts] Fall of SRAM voltage in a 3457A without external power

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I decided to try a little experiment on my 3457A, When on mains the SRAM gets 4.8 ~ 5 V. This does not seem to be well regulated, so I assume depends on mains voltage. Once power is removed, the voltage on the SRAM stays well above the battery voltage for some considerable time, which I assume is

Re: [volt-nuts] Fall of SRAM voltage in a 3457A without external power

2016-01-25 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 25 January 2016 at 11:50, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > In message < > canx10hcamahhhxqiao9bdzu03c2bbt787mr10rmnywk3oa8...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >ESD and leakage

Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-24 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 24 January 2016 at 21:24, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > In message < > canx10hadbw1u9ejc8_zgsk94k8az8vzg4ose+xngfwrali0...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >Opening the mete

Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-24 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 24 January 2016 at 22:16, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > In message < > canx10hcknsnxczjx8gccd2-t0j-jom7ybmncgdvis9ic3yv...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >The SRAM actually

[volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-24 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I've got a HP 3457A 6.5 digit multimeter - S/N 2703A04579. It's working fine, but I'm aware the battery must be at least 11 years old, as I first bought the meter 11 years ago. I suspect its due for a change. I'm trying to find a *reputable* source for a replacement. I want to avoid eBay, due to

Re: [volt-nuts] Wanted - UK source of a replacement battery (type LX 1634) for HP 3457A 6.5 digit multimeter

2016-01-24 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 24 January 2016 at 22:46, Poul-Henning Kamp wrote: > > In message

Re: [volt-nuts] Just back from cal

2016-04-07 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 8 Apr 2016 04:21, "Joseph Gray" wrote: > > In February, I sent my HP 3457A in for cal. In late March, I sent my > EDC VS330 DC Voltage Reference in for cal. Today, I just got the VS330 > back and thought I'd compare the two instruments. Did you send them to the manufacturers

[volt-nuts] Suggestions for 10 milli Ohm 0.04 % 100 W resistor

2016-05-17 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I have an HP 6674A power supply with option J06, which means that the PSU is 70 V @ 30 A rather than the standard 60 V @ 35 A . I've replaced a couple of bits in this and will need to replace some more, so it would be prudent to get this calibrated. The service manual calls for a 8.5 digit

Re: [volt-nuts] Keysight 3458A vs Keithley 2002 8.5 digit multimeters.

2016-07-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 18 Jul 2016 17:34, "John Phillips" wrote: > > Most labs never turn 3458As off. The longer they are on the lower the drift > rate. I would rather have an 20 year old meter with new batteries than a > new meter. If one buys a used meter, one has no idea if it has been

[volt-nuts] Don't bother changing a 3457A battery if sending to Keysight for calibration.

2017-02-01 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
Today I went to Keysight in Winnersh in the UK for a seminar on RF material measurements. We were given the opportunity to go for a 20 minute tour of the repair and calibration labs. Needless to say I took up the opportunity. There are 3 areas at Keysight in the UK. * Repair * Main calibration

[volt-nuts] Availability of 3458A in Europe after the end of 2016.

2016-10-29 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
The 3458A page on the Keysight website is interesting. "Notice for European Union Customers: This product is not updated to EU RoHS compliance and can be ordered via Keysight directly or Keysight Authorized Distributors until 31 December 2016. Beyond this date, the product can still be purchased

Re: [volt-nuts] low emf solder

2016-10-29 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 29 October 2016 at 14:51, NeonJohn <j...@neon-john.com> wrote: > > > On 10/28/2016 08:39 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > > > I wonder how practical it is to weld test leads, so there's no solder or > > thermal EMF. > > > > I kno

[volt-nuts] Is there a "standard" much better than a LTZ1000, but much cheaper than a Josephson Junction Array?

2016-10-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
The question about the Josephson Junction Array got me thinking. I wonder if there are any sort of technologies that can produce a voltage with much better stability than the LTZ1000, but without the cost of a Josephson Junction Array. A sort of half-way house. BTW, I see some rather battered up

Re: [volt-nuts] Low-cost Josephson Junction Array

2016-10-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 19 October 2016 at 20:15, Ken Peek wrote: > Well, I already have a 3458A, OK, quite an expensive multimeter. Otuside my budget for something I don't really need, but would like! $400K is *WAY* out of my budget. I was looking more for > something on the

Re: [volt-nuts] Is there a "standard" much better than a LTZ1000, but much cheaper than a Josephson Junction Array?

2016-10-20 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 20 October 2016 at 00:08, Poul-Henning Kamp <p...@phk.freebsd.dk> wrote: > > In message g...@mail.gmail.com> > , "Dr. David Kirkby (Kirkby Microwave Ltd)" writes: > > >The question about the Josephson Junction Array got me thinking. I wonder >

Re: [volt-nuts] Availability of 3458A in Europe after the end of 2016.

2016-11-13 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 13 November 2016 at 09:19, Alessandro Saporetti wrote: > Hi all > Just got back from Electronica in Munich where i did have a small > conversation with keysight people about 3458A Rohs issue, they have a vague > idea about when it will kick-in , but where sure about

Re: [volt-nuts] Availability of 3458A in Europe after the end of 2016.

2016-11-13 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 13 November 2016 at 14:17, Chuck Harris wrote: > RoHS does not apply to test equipment. > Where do you get that from? When I was looking briefly the other day, there did not seem to be a lot of exemptions. I'm sure Keysight must be a bit more on the ball than to put that

Re: [volt-nuts] low emf solder

2016-10-28 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 28 Oct 2016 15:25, "Juris L" wrote: > > Found reference to optimal emf solder composition cadmium/tin alloy > (70 %/30 %) in JJ array measurement article page 12. I wonder how practical it is to weld test leads, so there's no solder or thermal EMF. I know that this will

Re: [volt-nuts] Calibration of 34401A

2016-10-12 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 12 Oct 2016 10:31, "Poul-Henning Kamp" wrote: > > > In message <120112818.2234439.1476263954...@mail.yahoo.com>, Bruce Griffiths wr > ites: > > >Does anybody know if a 34401A can be adjusted by a competent 3rd party lab, > >or are the details of how to adjust the

[volt-nuts] Calibration of 34401A

2016-10-12 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I have a 'friend" (actually a person who I have never met, but is a pain in the ***). He sold a Agilent 34401A multimeter which the customer said is out of specification and can not be adjusted. Quickly scanning the measurent results, the meter is not showing results with any huge errors (say

Re: [volt-nuts] PCB Artist

2016-12-14 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 14 Dec 2016 14:14, "Dan Kemppainen" wrote: > If it's a one off board, with a handful of components anything should work. You can always redraw it later in something else. If you have 500 components, differential signals, and controlled impedance stuff that's a different

Re: [volt-nuts] [time-nuts] OT: ExpressPCB (cross-post from volts-nuts)

2016-12-09 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 9 December 2016 at 19:58, BIll Ezell wrote: > Sorry if I'm behind the times, just did a new project that required a pcb, > and ExpressPCB is my go-to vendor for one-off boards. I just noticed they > now provide the low-cost boards (fixed size, 3x5, quantity 3) that I've >

Re: [volt-nuts] Short term "standard" cell?

2017-03-12 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On Sun, 12 Mar 2017 at 17:03, Frank Stellmach wrote: > Hi Chris, > > > > Therefore, instead of poking around with these mediocre 10V > "references", I'd look for a possibility to get access to a 3458A, maybe > there's a friendly volt-nuts nearby. > > Frank > There

Re: [volt-nuts] Anyone got a photo of a 3458A with "new volt" printed on it?

2017-05-31 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 31 May 2017 at 20:57, Frank Stellmach wrote: > >> 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. > >

[volt-nuts] Anyone got a photo of a 3458A with "new volt" printed on it?

2017-05-30 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
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

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-18 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 18 September 2017 at 18:36, Todd Micallef wrote: > Dave, > > Another meter is the Cambridge LOM-510A. I am not sure if it is in your > budget but there has been a review made on EEVBlog. There is one currently > on eBay with a current amplifier that I have never seen

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 19 September 2017 at 20:32, Charles Steinmetz wrote: Looking at the pix, there appear to be lots of aluminum joints due to the > "built-up" construction, maximizing the potential for the sort of troubles > you are having. I would re-make the piece in brass, doing

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-19 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 18 September 2017 at 23:28, george wrote: > The reason that DC is used commercially to measure resistance is simple, > if you use AC you may well get the reactive component as well as the > resistance coming into play. > That may not be an an issue with a dual-phase

[volt-nuts] Power consumption of 3458A reference board / fitting one in a 3457A

2017-09-23 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I've got two different, but not totally unrelated questions. 1) Does anyone know what is the power consumption of the 3458A reference board? I was thinking of getting one, boxing it up with a battery, that allowed it to keep running without mains power. I would like to know the energy storage the

Re: [volt-nuts] Power consumption of 3458A reference board / fittingone in a 3457A

2017-09-23 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 24 September 2017 at 08:52, Bill Gold wrote: > David: > > Your answer to question #1. I have a spare reference board setup to be > powered up on the bench. > > I measure around 36 ma when it starts cold and then around 30 ma when > it > warms up to operating temp.

[volt-nuts] Best way to measure micro Ohms

2017-09-17 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I want to measure the resistance between two bits of aluminum. Each are 40 x 30 mm across. One is 250 mm long, the other is 8 mm long. I'm wondering is surface oxides are on the faces, so despite being held together with bolts, the resistance is perhaps not as long as I would expect. There's also

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-17 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 17 September 2017 at 20:12, wrote: > The question is what accuracy you need. > No a lot. I just want to find out if there's any voltage drops that are significantly higher than I would expect. The unit makes an RF transmission line, and the loss at RF is significantly higher

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-17 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 17 September 2017 at 21:58, Mitch Van Ochten < mi...@vincentelectronics.com> wrote: > The Keithley 2002 uses DC but automatically takes a reading of any offset > voltage and subtracts it (offset compensation). Rated accuracy on the 20 > ohm range (2 years) is +/- 26 ppm, and with 10 averages

Re: [volt-nuts] Solartron (aka Schlumberger) 7081

2017-10-03 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 27 September 2017 at 11:09, David C. Partridge < david.partri...@perdrix.co.uk> wrote: > I assume you've seen my website: Solartron7081/index.htm>? The last corporate owner of the Solartron > brand was Ametek, and their branch in Farnborough did calibrate them up to

Re: [volt-nuts] Power consumption of 3458A reference board / fitting one in a 3457A

2017-09-24 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 23 September 2017 at 18:03, Tom Knox wrote: > If you want I will send you a few to play with for a few months. > Thank you very much. I'd like to have a play. I sent you a private email. Someone suggested using the DCV:DCV ratio mode to look at two references, but I

[volt-nuts] Solartron (aka Schlumberger) 7081

2017-09-26 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
I've been offered a Solartron 7081 8.5 digit meter, but are having difficulty finding out much about this. Is there any "official" place where these can be calibrated? As far as I can see from a search of Companies House https://beta.companieshouse.gov.uk/company/02858371 Solartron Instruments

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-28 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 28 September 2017 at 19:17, ed breya wrote: > Hmm. Alternating the direction of the current repeatedly and processing > the results - sure seems like that is fundamentally an AC measurement too, > despite using DC measurement equipment. > > Ed I guess the point is

Re: [volt-nuts] Best way to measure micro Ohms

2017-09-27 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 27 September 2017 at 22:22, ed breya wrote: > I just noticed this discussion recently, so I'm late to the party, but > that never stops me from adding my one-cent's worth. > > David, regardless of the aluminum and other material issues, I think your > initial idea of using a

Re: [volt-nuts] Solartron (aka Schlumberger) 7081

2017-09-27 Thread Dr. David Kirkby (Kirkby Microwave Ltd)
On 27 September 2017 at 11:09, David C. Partridge < david.partri...@perdrix.co.uk> wrote: > I assume you've seen my website: Solartron7081/index.htm>? Yes I had. I believe your site has more about the meter than the sum total of the rest! I was surprised how little