Re: [volt-nuts] Shorting straps for test equipment banana jacks

[Steve - Home]

Hey Mark,

I just tried to order the shorting straps with 2 oz copper and 1 mm thickness 
as you recommended and it only allows .8mm thickness. Is there an option code 
hidden somewhere?

Thanks,

Steve




> On Jan 1, 2018, at 1:47 PM, Mark Sims  wrote:
> 
> I got in my latest PCB based shorting straps for test equipment banana jacks 
> from OSHPARK.  You can find them here:
> 
> http://www.eevblog.com/forum/metrology/copper-binding-post-shorting-straps-for-low-thermal-emf-alloytempering/msg1389056/#msg1389056
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Re: [volt-nuts] Solartron 7081 .. what to look for

[Steve - Home]

Pete,

Congrats! The 7081 is a good meter, although very slow when making 8.5 digit 
measurements. The key is only necessary for calibrating the instrument and can 
be bypassed with a clip lead to go into cal mode. I have the part number for 
the matching input connector somewhere but I'm traveling until March 18 so I 
can't lay my hands on it. If no one finds it before then I will have a look 
when I get home.

Steve




> On Mar 10, 2016, at 9:53 PM, Pete Lancashire  wrote:
> 
> I just won a Solartron 7081, hopefully did not pay too much.
> 
> I have 30 days ROR.
> 
> Other then the usual things in any used piece of equipment, obvious damage,
> Perfume of Allen Bradly, error messages What are some of the thing I should
> be looking for.
> 
> The bad news is I do not have a cable or key. Is the key needed to take the
> cover off ?
> 
> Someone in the past said the had the key type and a drawing or scan of the
> key
> are you still here ?
> 
> I could coble up a cable to do the basic E/I/R checks or is there someone
> in or near Portland Oregon that has one ?
> 
> Regards
> 
> -pete
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Re: [volt-nuts] AC calibration

[Steve - Home]

Fred,

The 3458A is 8.5 digits, which puts it into the standards category. They are 
used as lab standards in many, many labs. 

73,

Steve
WB0DBS



 On Aug 27, 2014, at 12:08 AM, pa4...@gmail.com wrote:
 
 Thanks, I did not new NIST has so much interesting information on their site. 
 
 
 
 
 I read the following on their site :
 
 multirange instruments with up to eight decimal digits of adjustability, are 
 not considered by NIST to be standards 
 
 
 
 
 Does that mean a HP3458 ? Fluke in the Netherlands used a HP-3458 and a 732 
 to calibrate the Fluke 5101 that  I'm working on at this moment (it failed 
 calibration due to some hardware faults) 
 
 
 
 
 Everybody thanks for the information. Turns out, a friend has a GR 1455AH for 
 me, that is some kind a AC KV divider. 
 
 I will test if the output of my HP 3400 is usable to connect a DMM. I have 
 one I restored a few years ago. Besides that someone mentioned to look at the 
 LT-1088.  
 
 
 But that has to wait until I have some more time. I only repaired 
 calibration, percission gear and RF stuff  for my hobby, but, not planned, I 
 started to do this on a commercial base too. See my (non commercial) site 
 about my collection calibration and other gear and projects  www.pa4tim.nl .
 
 Today the 5101 goes back to the custommer but he brings 2 other instruments 
 in need of some TLC and a precheck before they are shipped to Fluke for 
 calibration.  And yesterday an other company asked if I want/can repair a GM 
 safety tester (a sort of megger on steroids) that died during calibration.  
 
 
 Fred
 
 
 
 Verzonden met Windows Mail
 
 
 
 
 
 Van: acb...@gmx.de
 Verzonden: ‎dinsdag‎ ‎26‎ ‎augustus‎ ‎2014 ‎18‎:‎56
 Aan: volt-nuts
 
 
 
 
 
 Dave,
 
 the title is: 
 Thermal Voltage Converters and Comparator for Very Accurate AC Voltage 
 Measurements
 by E.S.Williams.
 
 Adrian
 
 
 Gesendet: Montag, 25. August 2014 um 19:32 Uhr
 Von: Dave M dgmin...@mediacombb.net
 An: Discussion of precise voltage measurement volt-nuts@febo.com
 Betreff: Re: [volt-nuts] AC calibration
 
 Adrian,
 Do you have a link or title for the NIST paper that you mentioned?
 
 Dave M
 
 
 acb...@gmx.de wrote:
 fred,
 generally you raise a good point, I had the same issue of calibrating
 an ac voltage to a high level of accuracy. you need this e.g. to
 validate the self.cal of a 3458a or other precison stuff like the
 8506a0.   
 
 what i would recommend to do if you want to keep costs down is:
 in a nutshell, get a thermal converter in the lowest range you need
 and a second one on range above. build a set of resistor range
 extenders (rf type with appropriate connectors and housings) to
 expand the range to where you need to be max. get one of the thermal
 converter calibrated (the higher one usually, and you need to havr 
 good cal lab, should be 10ppm accuracy) and use it to calibrate the
 rest. generally, up to 20khz, the accuracy is some 20 ppm anyway for
 thermal converters! at higher frequencies, due to reflections and
 stray capacitance/inductance influences, the accuracy decreases. the
 resistor range extenders though, if build up correctly, only have a
 few ppm impact (there is a paper from nist on that, but this is only
 typical). you can calibrate all converters to the one you got
 externally calibrated. do some research in the web, when you do the
 calibration, you need to determine the so-called constant N. then do
 an ac, dc+, ac, dc-, ac measurement between the the two and establish
 the deviation, also establish the error propagation. the end result
 will be a set of highly precise (low inaccuracies9 thermal converters
 good enough to calibrate a 3458a an better devices. if you want to
 spend the money, you could also buy a set of converters/range
 resistors (with/without a 540), that typically is a few k altogether,
 while a single device sometimes is available for below 100 bucks. you
 need to have a stable 7.5 digit nanovoltmeter though for the
 measurements of the tvcs (34420a or 2182 typically ) and precision
 (stable) dc and ac sources. but in the end, all you need is a single
 calibrated thermal converter.
 
 adrian
 
 
 
 Gesendet: Montag, 25. August 2014 um 18:38 Uhr
 Von: Dave M dgmin...@mediacombb.net
 An: Discussion of precise voltage measurement volt-nuts@febo.com
 Betreff: Re: [volt-nuts] AC calibration
 
 Well, you sort of answered your own question.  The equipment is
 called a Thermal Transfer Standard, but instead of thermistors, it
 uses a thermocouple.  Look at the manual for the Fluke 540B
 (http://bama.edebris.com/manuals/fluke/540b/) and you'll see how
 it's done. Basically, the AC source is input into the transfer
 standard, and the standard's internal reference voltage is adjusted
 for a null on the galvanometer.  Leaving the reference voltage
 setting alone, a DC voltage is input into the unit, and the DC
 source is adjusted for a null on the galvanometer.  At that point,
 the AC voltage source is equal to 

Re: [volt-nuts] Datron 4910 components

[Steve - Home]

Thanks Frank, much appreciated!

Steve
WB0DBS



On Aug 20, 2013, at 4:27 PM, Frank Stellmach frank.stellm...@freenet.de wrote:

 Steve,
 
 yep, it's in the LTZ100 thread.
 We discussed intensively the sense or nonsense of those slots in the Datron 
 PCB design, which is very often (blindly) copied by others...
 
 Mickle T. contributed the already known schematics and he measured all 
 resistor values of the Vishay array.
 
 Then, quarks simply added a schematic of this array, which he received 
 directly from Vishay, obviously.
 
 So, Datron used 21 Ohm in series with the Zener for better T.C. (originally 
 50ppm/K), 9k/659 as initial divider for temperature regulation (altered by 
 the external temp. PWM), 128 Ohm for the Zener current, 39k as collector 
 resistor for the reference transistor.
 
 There's no complete schematic yet, but now it's possible to finalize that.
 
 Here's the link:
 
 http://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/300/
 
 Frank
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