[volt-nuts] Economical Standard Calibration

[Dallas Smith]

Hi Bob,

I also heard about this  technique, probably on 'volt-nuts'. They 
connected 16 LM199's summed
  together isolated with about 500 ohms each. This averaged the voltage 
and reduced the noise.

But not knowing the absolute voltage will not calibrated my Fluke 731b. 
It appears if I want
  a calibration, I'll have to play with the big boys and spend the bucks.

Dallas


On 3/8/2014 10:05 PM, Bob Albert wrote:
> I have five AD587 switch selected, powered by a wall wart.  They seem to be very good, but of course not in the league of the units discussed here.
>
> In any case, they are 10V and all within about a millivolt.  If I average them I should get a statistically valid accuracy improvement, neglecting any systematic errors in their manufacture.
>
>
> While watching the display on my HP 3456A I begin to realize that my need for 'exact' voltage isn't really so great.  Certainly what I have is more accurate than anything I will ever really need.  But it's fun to see the variation and watch the drift and compare my other high class voltmeters.  The 3456A manual says to wait an hour for it to warm up and that seems reasonable; nearly all the drift is gone by about 45 minutes.
>
> Bob
>
>
>
>
> On Saturday, March 8, 2014 5:34 PM, Dallas Smith <dosmith at outlook.com> wrote:
>   
> I'm in west Michigan, Holland. As far as accuracy the manual states  ±10ppm for 30 day or ±30ppm per year for the 10v output .
> I need it to calibrate my (modified with reference oven)  EDC (Electronic Development Corp.) model 520a. Which I calibrate my Fluke 510a with a Fluke 720 voltage divider. I use the 510a to calibrate DB voltage for my audio test equipment. I also have a Fluke 8505, Fluke 8800 and Data Precision Model 2500.
>
> So if I can achieve ±50ppm per year this would be sufficient, but better would be nice since they may not be calibrated every year.
>
> I’m just a hobbies audio engineer that designs audiophile equipment and other interesting projects not related. So sending it to fluke is not economical for me.
>
> Since Joe suspended  operations for his SVR-T with low cost calibration. I purchased one and put it in a 35°C oven and it seems to outperform the Fluke 731b as compared to my 8505 for drift. I will have three 10 volt references in my lab to track uncertainty.
>
> So are there any calibration labs that will calibrate my 731a and my home brew reference’s?
>
>
>
>
>> Date: Sat, 8 Mar 2014 16:00:41 -0700
>> From: nova at npgcable.com
>> To: volt-nuts at febo.com
>> Subject: Re: [volt-nuts] Economical Standard Calibration
>>
>> Dallas,
>>
>> How accurately do you need the 731B set?
>>
>> Where are you located? I am in Flagstaff, Arizona
>>
>> I have four 731s, and I know how to calibrate them.
>>
>> I also have a 3458A and a Fluke 7001 that goes to Fluke for calibration soon. I
>> do not know the turnaround time.
>>
>> Joe
>>
>>
>>