Hello, For my 5cents worth, I also found Fluke 8506A's to be satisfactory - so long as they work. I only have one good remaining unit that does AC volts as well as DC. I like the HP 3458A for AC volts, but always need to apply corrections for serious AC volts work. A better solution I now use is the Datron 4920 units which are an order of magnitude more accurate than the 3458A across their full bandwidth. However, be aware of their input impedance and selection of cables - always use short coaxial. The 4920 impedance is around 100k to 400kohm (mostly frequency dependant) and this also varies during its sampling period. Otherwise they are great units, in the same ball park as a Fluke 5790 but way cheaper. For an AC source I thoroughly recommend the Datron 4200 or 4700 series, which are also way cheaper than the near equivalent Fluke 5700. Ben ---------------------------------------- From: acbern@gmx.de Sent: Wednesday, July 09, 2014 9:29 PM To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Subject: Re: [volt-nuts] AC Voltage Measurement Standards J.L., it really depends on what level of accuracy you are looking for. The gold standard obviously is the Fluke 792A. That is probably not an option. The Fluke 8606 is more on the lower end side (dont get me wrong, compared to the 792A), it does not really bring much improvements compared to the 3458A operated in the AC SYNC mode, but maybe it is good enogh for what you want to do. In that range are also e.g. the R&S ac voltmeters, but their focus is more in the higher frequency area. Very good accuracies are achieved by thermal converters (Ballantine...). You can do DC to AC comparison measurements with a few ppm accuracy. But measurements are slow, and you need a nanovolt meter. I personally did the following: I got a Ballantine 1605A transfer voltmeter. This is comparable to the 792A in a way, except it was much cheaper. It is automatic, much easier to use than the Fluke 540 and goes up to I think 100MHz. This can be used for percision calibrations as a working standard. The calibration of this meter as well as others (e.g. the 3458A in its AC mode) I am doing with a set of thermal converters (0.5V to 100V). One of which (10V) has been externally calibrated up to 30MHz, cal of the others are derived from it. That way I am deriving everything from a very precisely (few ppm) calibrated 10V TVC. Overall, this saves cost on the calibration side, allows for high accuracy and measurement speed is good. > Gesendet: Mittwoch, 09. Juli 2014 um 06:20 Uhr > Von: "John Phillips" > An: mitch@vincentelectronics.com, "Discussion of precise voltage measurement" > Betreff: Re: [volt-nuts] AC Voltage Measurement Standards > > J. L. , > I do not know what level you are willing to pay for. I do not work in a > real high end lab but we seem to get by with checking our secondary > standards with a 3458A before and after we send it to gary to be > calibrated. We use our 10 volts and 10K resistor to calibrate the 3458A > before we send it in and then after. We look at the before and after data > as well to come up with new values for the units. Comes down to using the > 3458A as the primary standard filtered by our history. The different AC > measurement methods in statistical mode can give you a good idea where your > AC values really are. > > I would like to know how that compares with what the extra hardware can do. > > > > On Tue, Jul 8, 2014 at 7:52 PM, Mitch Van Ochten mitch@vincentelectronics.com> wrote: > > > Joe, > > > > I used a Fluke 540 for a while, and also the Fluke 8506A. The Fluke 540 is > > MUCH more difficult to use. You need to flip the switch between two > > positions rapidly and the results you get depend somewhat on how "rapidly" > > you make the transition. For AC volts the 8506A seems very nice. > > > > > > Best regards, > > > > mitch > > > > -----Original Message----- > > From: volt-nuts-bounces@febo.com [mailto:volt-nuts-bounces@febo.com] On > > Behalf Of J. L. Trantham > > Sent: Tuesday, July 08, 2014 9:46 PM > > To: Discussion of precise voltage measurement > > Subject: [volt-nuts] AC Voltage Measurement Standards > > > > I've been thinking about adding an AC Voltage Measurement Standard to my > > shop. > > > > > > > > It would appear that most of these have to do with thermal converters. > > Does > > anyone have any thoughts about this? > > > > > > > > I've been thinking about a Fluke 540B, 8506A, or a collection of A55 > > Thermal > > Converters. I have accurate DC measurement tools and DC standards. > > > > > > > > I would appreciate any thoughts. > > > > > > > > Thanks in advance. > > > > > > > > Joe > > > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > > > > -- > John Phillips > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.

Ben, Do you have the 4921 Current Shunt Adapter option for the 4920? I have not found any information on it other than what is listed in the 4920 user's handbook. It mentions the unit simulates the impedance of a 540B. The guide says that the instructions are included with the 4921. Do you happen to have a copy of that document? The 4920 user's guide is on the KO4BB website. Thanks, Todd On Thu, Jul 10, 2014 at 5:17 AM, ben <ben@veritechmeasurements.com.au> wrote: > Hello, For my 5cents worth, I also found Fluke 8506A's to be satisfactory > - so long as they work. I only have one good remaining unit that does AC > volts as well as DC. I like the HP 3458A for AC volts, but always need to > apply corrections for serious AC volts work. A better solution I now use > is the Datron 4920 units which are an order of magnitude more accurate than > the 3458A across their full bandwidth. However, be aware of their input > impedance and selection of cables - always use short coaxial. The 4920 > impedance is around 100k to 400kohm (mostly frequency dependant) and this > also varies during its sampling period. Otherwise they are great units, in > the same ball park as a Fluke 5790 but way cheaper. For an AC source I > thoroughly recommend the Datron 4200 or 4700 series, which are also way > cheaper than the near equivalent Fluke 5700. > Ben > > > > >