I have several voltmeters in my lab, and like the man with two clocks who never knows what time it is, I have meters that give different answers.
In order to resolve this problem I want to build a Traveling Standard (TS) that I can send out to be measured by other volt nuts with better meters than I own.
Here is the first message I posted about a TS to the volt-nuts mail list.
I was very pleased with the responses I got back, which included this one. What a great reply - it gave me lots to think about.
Here are my design notes.
A proposed TS protocol.
I have posted some pictures as the unit is developed, along with some plots of the voltage versus time and temperature
The detailed schematic is attached to this page.
|2012-01-04 - 2012-01-08||69.955||1||3458A||20||6.9973253500||0.0000032489||20||5.0005381000||0.0000085156|
|2012-04-19 - 2012-04-21||2||3457a
(7.5 digit mode)
|2012-08-20 - 2012-08-20||80.9||3||3458A(1)||999||6.9971877711||0.0000010629||999||5.0005314107||0.0000009556|
|2012-08-18 - 2012-08-18||82.76||3||3458A(2)||999||6.9971967204||0.0000009491||999||5.0005410164||0.0000011941|
|2012-08-05 - 2012-08-05||80.96||3||7081||66||6.9972224758||0.0000030342||69||5.0005511870||0.0000006535|
|Average of averages||6.9972476635||5.0005362028|
|STDEV of averages||6.37E-005||1.18E-005|
The measurements reported by Volunteer 1, taken from 2012-01-04 through 2012-01-08, are attached below.
The measurements reported by Volunteer 2, taken from 2012-04-19 through 2012-04-21, are attached below.
Volunteer 4 is providing long term drift data, taken with multiple HP3458As calibrated against a Fluke 732A. Here are some plots of his data:
|TS Schematic (pdf)||11.8 KB|