[volt-nuts] Simpler Transfer Voltage Standard

[WarrenS]

Here is another way to make a transfer voltage standard for KISS Nuts.

I've mounted a selected 1N825 type reference diode and its 'Zero TC' current 
setting resistor 'inside' a dual banana plug to made a KISS simple 6.2xxxxxx 
transfer standard.
To use it, I plug it into a 0.01% or better 10 Volt reference supply capable 
of supplying  5 ma.
Nothing else needed except for a good linear voltmeter.
The 10 V reference provides all needed power.
Using JUST that small, self contained Plug-In,  I'm getting short term 
transfer repeatable under 1PPM

I still need to do lots of testing to see what happens when I torture it and 
mail it.
If successful, this would make a simple and cheap 6.2v transfer standard.
Still TBD what kind of mailable transfer accuracy to expect from it.
If found helpful, it could also be plugged into a small standard, 
rechargeable 9 volt battery to keep it 'warm' for up to 5 days
by using ONLY  a " 9V 600mA Lithium Rechargable Battery 6F22 ", something 
like EBay # 110736916935, which is a $6.
That would more than double the size and weight of a mailable packaged, So 
I'll try and do without it.

Please note that not all 1N825, 6.2 volt reference diodes are created equal.
This one is cherry picked from my special supply of ones which I've:

1) Aged at 50 MA for a year,
2) Run in at 7.5 MA for another year,
3) Then No power Aged for another 5 years,
4) Tested for stable and repeatability for better than 1PPM,
5) Tested for low noise for better than 0.1PPM,
6) Has a room temperature 'Zero TC' under of 0.1PPM
7) and the Zero TC current is a under 5 ma.


Many thanks go to J.H.,  a fellow Volt-Nut for the Plug-In idea.

ws

***** sniped from 'Traveling Standards' Postings **************

>"ZERO TC" means that over some temperature range there is NO
>significant change in the output.
>This family of zeners have a reasonable wide and flat room temperature
>True "ZERO TC" current point that can easily be found and set.
>Parts can be selected with noise and stability well under 1 PPM,
>which is much better than any of the  LM399's that I've tested.

>If you want something Kiss simple that will more than do what you're asking 
>for.
Take an AGED & SELECTED 1N825 type zener. (or 1N827, 1N829)
Select a stable resistor that will apply it's measured  "Zero TC current"
(which is generally between 4 and 9 ma),
set to use 15.0000  volts or whatever stable PS voltage you care to use.
Measure the zener's voltage and with only two parts and some
fun Volt Nut time you have a 6.2xxx volt reference.

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[volt-nuts] Traveling Standards
Bob Smither smither at c-c-i.com

Fellow voltage aficionados ,

If this has already been discussed - my apologies.  I could not find
this topic in the past several months of list archives.

Like many of us, I have an ever growing collection of voltmeters and
related instruments.  Like the man with two clocks who is never sure of
the time, I now have enough volt meters to have doubts about all of them.

So - I was wondering if those on this list with really good voltage
measurement capabilities would be willing to help those of us without.

What I have in mind is creating a small voltage reference circuit based
on one of the many available IC references that is stable enough in both
time and temperature to use as a transfer standard.  I am thinking that
the actual voltage is not important, just the stability.  Using the ICs
that I am familiar with the actual reference voltage would be around 5,
7, or 10 volts.  Said reference would be mailed to a willing list member
who would record his reading of the reference and mail it back.

I don't have such a reference yet, but have breadboarded a couple and
the idea seems like it might work.

My first objective would be to obtain a reference that I could use to
get all my meters to agree.  Since the best meters I have are an HP3455A
(best accuracy about 20 - 40 ppm, and only for 24 hours) and an ancient
(but very usable) Fluke 883AB (best accuracy is 100ppm), I would be very
happy to have a reference that I could trust to 10ppm.

So - two questions for the list:

1.  Does this sound feasible?  Am I overlooking anything that would keep
me from being able to transfer a 10ppm known reference?

2.  Any list members that would be willing to help with this?  I
envision mailing a small package with the reference in it along with an
enclosed, postage paid, return box.  I am asking for a member that would
take the reference, apply power, let it warm up, record the room
temperature and the reference voltage to within 10ppm, and return it to
me.  If you prefer to respond off-list - smither at c-c-i.com.

BTW - I live in Friendswood, Texas (near Houston).  Any fellow nutters
close enough that I could hand deliver the reference?

Best regards,

Bob Smither