[time-nuts] OT: Basics of voltage calibration?

Daun Yeagley daun at yeagley.net
Wed Mar 18 09:44:50 EDT 2009


That reminds me of a prank we pulled off in a measurements class in college
many years ago. Of course we were working with galvanometers and standard
cells, and the "usual" warnings.
We had some cloth insulated hook up wire, so we pulled the wire out and put
part of it back in the insulation so that it looked real, and then "shorted"
the standard cell with this setup. We waited for the professor to come by
and let him see what we had done.  After he came down off the ceiling, we
pulled the insulation back off so he could see that we hadn't really shorted
it after all.  It's a good thing he had a great sense of humor. (I think he
is the type that would have pulled the same sort of stunt).

Daun

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Jean-Louis Oneto
Sent: Tuesday, March 17, 2009 11:49 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] OT: Basics of voltage calibration?

I suppose it was to to keep the electrolyt to slam around ;-} ???
Jean-Louis Oneto
----- Original Message -----
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'" 
<time-nuts at febo.com>
Sent: Sunday, March 15, 2009 4:24 PM
Subject: Re: [time-nuts] OT: Basics of voltage calibration?


> Yes, never load a standard cell.
>
> It's standard practice to put a jumper across the terminals of a
> galvanometer for shipping, so the needle (or mirror) doesn't slam
> around.
>
> Some years ago, I got a standard cell from eBay. The terminals had been
> shorted for shipping.
>
> Bill Hawkins
>
>
> -----Original Message-----
> From: Jürg Kögel
> Sent: Sunday, March 15, 2009 7:36 AM
>
> A good reference is the old Fluke publication "Calibration - Philosophy
> in Practice"
> by Steve Spang. (1975)
>
> Be very carefull with standard cells! Never load a cell. Use the cells
> only with high ohm null detectors.
> A loaded cell need a long time for regeneration (or come back never to
> the old value!)
>
> I think a good zener reference is a better practical solution for today.
>
> Juerg
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 


_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.





More information about the time-nuts mailing list