); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Hi John:
How does it compare to the Linear LTZ1000? Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam Neon John wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > On Tue, 06 Nov 2007 11:57:27 +0000, Joe McElvenney <[EMAIL PROTECTED]> wrote: > > >>Anyone know of a simple way of producing an AC voltage standard >>suitable for general workshop use without reference to another >>one? About one percent would be good enough, wave shape and >>frequency accuracy not important (wash my mouth out). I have a >>Weston Cell for DC voltage calibration, a Rb one for frequency but >>nothing for AC volts. Perhaps there is a chip out there that >>clocks between accurate limits that I could use as a source? > > > If a simple square wave will do then one of the simplest and yet most accurate > sources is to switch a known DC reference using a mercury wetted reed relay. > A dry > reed will work but will bounce a little. The small reed relays as were > ubiquitous in > data acquisition systems up into the 80s can switch at 150 hz or better. > Driving the > coil of the relay with stepped-down line voltage is a good solution. > > You probably know this already but I'll mention it anyway. You can't draw any > appreciable current from that weston cell and it remain within specs. Even a > 1 meg > scope probe is too much. I'd use a DC power supply or battery and a quality > DVM > (which is probably more accurate than the standard cell) instead. > > I started in metrology in the time when the standard cell was the best there > was. > Boy, am I glad that era is gone. I still have one just to stimulate old > memories but > my lab standard is a precision 10 volt reference IC. I don't recall the part > number > but both National and Burr-Brown make 'em. Untrimmed accuracy is something > like > 0.01%. That's better than my boat anchor Fluke meter calibrator! > > John > -- > John De Armond > See my website for my current email address > http://www.neon-john.com > http://www.johndearmond.com <-- best little blog on the net! > Tellico Plains, Occupied TN > Save the whales, collect the whole set! > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
