Electronics > Metrology

Volt Nutting Newbie

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BertSP:
I have recently jumped-in the volt thing addiction. My arsenal consists of:
Agilent 34401A,
HP 3457A,
Fluke 45,
GWInstek GDM 8251A, purchased in reverse order.
I am waiting for a Fluke 3330B calibrator that I just acquired.
I would like some advice as to how to proceed to get this gaggle working in unison and which one I should get Calibrated/Adjusted first (I doubt they all sing to the same sheet of music)
This is a new field for me as I collect mostly Tektronix analog scopes.
I will probably need some hand-holding and parts guidance on the 3330B.

Thanks for your help.
 

cellularmitosis:
Great to have you Bert!

I have a 332B calibrator which is in need of repair -- it works, but if you log the voltage you will see that it will stabilize for a few hours, and then start wandering around by a few hundred millivolts for a while, then stabilize again, etc.  I'm not certain, but I believe the 3330B may be based around a similar circuit, but is a bit younger.  It may suffer from the same sorts of issues (I.e. You are probably going to need to replace a few capacitors here and there).

Do you have data logging set up with any of your meters?  I'd say your first step is to evaluate the stability of your 3330B by logging it for 24 hours or so.

You've got a great start here -- the 34401A is probably the best value available for budding volt nuts who haven't yet ascended to a higher plane of existence (by purchasing a 3458A).  The 34401A gives 7.5-digit resolution over its data logging interface, supports 10GOhm on the 10V range, is the easiest to get started with data logging (use "talk only" mode on the serial port), and is both plentiful and old enough that it can be had for under $250 on ebay if you are patient and lucky.

Hook up your 3330B to one or both of the 34401A and 3457A (using both would help deduce if any strange behavior is due to the 3330B or due to one your meters), take some data, and then make a plot to see where you are at.

VK5RC:
As a junior volt-nut, I would start by doing some measurements and see how repeatable you can get. In my set up, I have found multiple issues with things such as temperature of the lab, smpsu for the lights, even other test equipment switched on at the time, lead types even the computer! Once these issues are tied down - then think if you really need to calibrate - this is an ongoing process over years really, as points, error bars, uncertainties etc.
The serious guys like mrdiodes, Edwin Pettis, drfrank, TiN etc have said a lot - certainly worth reading their posts.
Robert

BertSP:
Good points. I need to map out my inventory and see where the biggest problems are first and then tighten the noose, so to speak. The learning curve is staggering, especially when I look at the sheer volume of printed instruction user and service manuals. Chasing that elusive last digit of precision will get you going crazy no doubt. I will try to post some feedback for other newbies as I go through each piece of equipment and see what kind of history they have. Buying off eBay is a hit and miss.

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