Products > Test Equipment
Cheap, not Chinese, Voltage reference for DIY meter calibration
GigaJoe:
since 587 not available in overall
AD588 + thermal correction
https://www.ebay.com/itm/323780690966?
dazz1:
Hi
I updated the BOM for the Elector Voltage Reference here: https://www.eevblog.com/forum/testgear/elektor-voltage-current-calibrator-project/msg5643277/#msg5643277
It looked like a viable option until I priced the DAC and LCD.
This leads me to conclude that the most cost effective and versatile option would be an old bench multimeter (7 1/2 or 8 1/2 digit) with an aged and stable voltage reference, combined with a reasonably priced process calibrator.
That combination would provide the same capability, with greater functionality, than the Elektor device. That doesn't mean I wouldn't like to build the Elektor reference.
tggzzz:
Too complex >:D
Why not reuse the concepts in old differential voltmeters? That avoids the need for calibrated high resolution voltmeters; all you need is something that reads 0V accurately (e.g. the crappy 20kohm/V 2% moving coil meter at the back of your storecupboard!)
A high voltage is divided down by a Kelvin-Varley divider. The divided voltage is compared with the known reference voltage, and the KVD ratio twiddled until they are the same. From that you can calculate the high voltage.
You can get 7-decade KVDs on fleabay, capable of having 1kV as the high voltage.
If you look at the Fluke 893 manual, you will see that's what is inside.
That's the mechanism we used at school to measure voltage to 0.1% using a 2% meter and 1m of wire. We could have measured to 0.01%, but that would have required a 10M piece of wire.
dazz1:
--- Quote from: tggzzz on September 15, 2024, 09:11:35 pm ---Too complex >:D
...
That's the mechanism we used at school to measure voltage to 0.1% using a 2% meter and 1m of wire. We could have measured to 0.01%, but that would have required a 10M piece of wire.
--- End quote ---
Too simple >:D
You obviously don't understand the concept of over-engineering. ::)
Although I did help my daughter with a school science project. She was able to measure the weight of air compressed in a balloon with a stick, string and paper clips. That was waaaay too simple, but remarkably accurate. 8)
My main problem is that the Elektor Voltage reference is the solution to a problem I don't have.
tggzzz:
--- Quote from: dazz1 on September 15, 2024, 11:22:32 pm ---
--- Quote from: tggzzz on September 15, 2024, 09:11:35 pm ---Too complex >:D
...
That's the mechanism we used at school to measure voltage to 0.1% using a 2% meter and 1m of wire. We could have measured to 0.01%, but that would have required a 10M piece of wire.
--- End quote ---
Too simple >:D
You obviously don't understand the concept of over-engineering. ::)
Although I did help my daughter with a school science project. She was able to measure the weight of air compressed in a balloon with a stick, string and paper clips. That was waaaay too simple, but remarkably accurate. 8)
My main problem is that the Elektor Voltage reference is the solution to a problem I don't have.
--- End quote ---
Playing like that with your daughter is fun :) Now ask her to calculate the weight of a fully developed cumulo nimbus cloud. Zero it ain't :)
(Since you are in NZ, start your daughter flying gliders before she can start to drive a car. My daughter had great fun learning a lot of things that way.)
And apparently you do have a problem, whether or not the Elektor reference would solve it >:D Welcome to the rathole ::)
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