Re: [volt-nuts] AC Voltage Measurement Standards
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: acb...@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 RS 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: mi...@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 mi...@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-boun...@febo.com [mailto:volt-nuts-boun...@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
[volt-nuts] fluke 5200a repair
Hi Gerd and Charles, Thanks for the input it has given me other things to think about. I checked the output of pin 6 of U1 and I get a voltage variation of 10.2 mv from +15 to -15v adjustment on R6, so that appears to be working correctly. Now the fun starts :- using my HP 3478A to measure the dc on the output terminals I get a reading of 0.9mv on the 1 volt range, 0.3 mv on the 10 volt range, and 1.8 mv on the 100volt range. As a quick check of wether C8 may be leaky I pulled Q38 out of it's socket and got a constant DC out on the output terminals of 0.22mv on all three ranges, so maybe C8 is leaky? Using a fluke 77 3.5 digit multimeter yields vastly different DC readings, up to 5.5 v on the 100 volt range, so I suspect the Fluke 77 is reading some of the AC component on the output terminals even though DC is selected. Last night I did check the input and output on the amplifier, and on the 1 v range I was getting an input of 1v and an output of 3 volts, so the gain was correct, I did not check it on the 100v range though to see if the gain was 30. The input and output was a good clean sine wave on the amplifier. I have previously checked the 190 volt + and - supplies and they were spot on, but I will check them again before I pull the amplifier board apart again to remove C1 and C8 to test with a higher voltage other than the battery voltage of the multimeter, to see if they may be leaking at a higher voltage. Thanks, Ken - Message: 2 Date: Wed, 09 Jul 2014 14:21:13 -0400 From: Charles Steinmetz csteinm...@yandex.com To: Discussion of precise voltage measurement volt-nuts@febo.com Subject: Re: [volt-nuts] Fluke 5200A repair Message-ID: 20140709222123.lmbgv...@smtp2o.mail.yandex.net Content-Type: text/plain; charset=us-ascii; format=flowed Ken wrote: R6 slider to U1 varies from +15v to -15v but the output of U1 only varies by mv's, I put this down to the loading of R9 to earth on the input to pin3 of U1 (221 ohm),only allowing a small variation to the input on pin 3 of U1, maybe this needs further investigation! Look at the circuit. The 100k potentiometer (R6) feeds a voltage divider composed of R8 and R9 (464k and 221 ohms, respectively). The tap of this divider feeds the reference input of U1. R8 and R9 attenuate the +/- 15v range of R6 by a factor of 210, so the divider tap voltage (i.e., the reference voltage for U1) only varies +/- 7.14 mV from ground for the full range of R6. U1 is an integrator, so it has lots of gain at DC (Q38 switches the integrating capacitor to give two time constants). If one of these capacitors is leaky or shorted (or there is another leakage path from Pin 6 to Pin 2 of U1), it would reduce the gain of the integrator and could produce the symptom you are having. Best regards, Charles -- Message: 3 Date: Wed, 09 Jul 2014 14:29:40 -0400 From: Charles Steinmetz csteinm...@yandex.com To: Discussion of precise voltage measurement volt-nuts@febo.com Subject: Re: [volt-nuts] Fluke 5200A repair Message-ID: 20140709222949.tnbeu...@smtp2o.mail.yandex.net Content-Type: text/plain; charset=us-ascii; format=flowed Oops! the divider ratio of R8/R9 is 2100, not 210. Best regards, Charles Message: 4 Date: Thu, 10 Jul 2014 18:25:32 +1000 From: Gerd ad...@controlelectronics.com.au To: Discussion of precise voltage measurement volt-nuts@febo.com Subject: [volt-nuts] Fluke 5200A repair Message-ID: 53be4dfc.7090...@controlelectronics.com.au Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hello Ken, The offset adjustment is about +-7mV to the input of U1. The amplifier has a gain of 3 or 30 so adjustment is small. Is the problem the same on both the 10V and 100V ranges? Is the amplifier producing the full output voltage? Is it distortion free? Are both the 190V regulators working correctly? Regards --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ 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.
Re: [volt-nuts] AC Voltage Measurement Standards
Todd and anyone else would is interested, Measuring a Thermal Converter against another Thermal Converter is a bit of a black art. The main problem is thermal converters are a square law device that is if you change the input voltage by a factor of 2 the output voltage will change by a factor of approximately 4. Now I say approximately because for most thermal converters like the Fluke 540B, A55, Ballantine and Holts the actual factor can be anywhere from 1.4 to 1.8 due to losses in the thermal converter. In the literature you often see this factor refer to as the N factors. Each thermal converter will have its own N factor which must be measured to make sense of the measurements. It even becomes more difficult in that the AC-DC difference of a thermal converter is defined as (Vac-Vdc)/Vdc where Vac and Vdc are the inputs to a thermal converter which give an equal output from the converter. Also Vdc is the mean of the forward and reverse DC voltages. The problem is that when you have two converters connected in parallel you cannot balance both converters AC and DC inputs to produce equal voltage out of the converters at the same time because each converter has its own AC-DC difference and its own N factor. It anyone is interested I can send them a technical paper that describes this process and the appropriate math to use but I cannot send it to the list due to copyright issues. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Todd Micallef Sent: Thursday, 10 July 2014 2:36 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] AC Voltage Measurement Standards I would like to know more about your setup. Which source(s) are you using for the input and which nanovoltmeter(s) are you using to transfer the 10V TVC to your other converters? I remember you asking on PMEL forum about the accuracy of using a 34420A nanovoltmeter. I did not see a response as to whether you opted for an alternative like Keithley 2182(A) or a low noise preamplifier connected to a 3458A. I have done some reading about how NIST transfers their calibrations using two TVC's in parallel and I am guessing that is what you are doing. http://www.nist.gov/pml/div684/acdc/tcs.cfm To transfer the accuracy up/down to other TVC's at different rated voltages appears to be a difficult task since they typically need at least half the rated max voltage to be within spec. It would be similar to starting with a SR104 standard and transferring its value through a set of SR1010 and SR1050 resistors using an ESI 242. I have a few AC sources, and I would like to be able to verify my TVC's without sending all of them out for cal. Ballantine quoted $600+ per TVC and I haven't checked what Fluke would charge for each A55. Todd 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. ___ 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ 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.
Re: [volt-nuts] AC Voltage Measurement Standards
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 b...@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 ___ 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] Desperately seeking OPTION 10 for Datron 4708
I am looking to purchase OPTION 10 slide in board for the Datron 4708 Multifunction Calibrator. If anybody has a parted out unit and can sell me just the option 10 board i would appreciate it dearly! Thank you for considering! Chris ___ 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.
Re: [volt-nuts] AC Voltage Measurement Standards
I have a set of 7 TVCs, from 1 to 100V. having them all calibrated externally is just too expensive. There is no doubt that having all 7 TVCs calibrated at NIST or PTB, wherever you are, is much more precise, I will just not spend it and live with the accuracy I get. As source I am using a Datron 4808, as nanovolt meter an Agilent 34420. Problem with this is, you pointed it out, Agilent does not specify transfer accuracy, I am in contact with them, so far no outcome though, not sure there will be any. So I have not yet completed my error calculation for the TVC cal. I will probably end up doing some calculations based on data sheet an then vaildate by measurement. Need that on the 10mv range only, so effort is limited. additionally I also have a ratio transformer, which is good to about 10kHz, that also allows for validating the TVC results by comparison in lower frequency ranges and narrow down the tolerances. I do have a 182-M, but do not trust it, I saw a lot of drift doing some other measurements although it passes performance verification, and I just got a 2182, which has an issue that needs to be fixed first. I need to say the 34420a is very stable with the digital filter switched on and you can see the nanovolts walk until the TVC stabilizes. vice versa, if you have an issue in the setup (thermal drifts...), you also seethat very well, so the filter is not hiding this. as far as your comment re. calibrating a set of resistor cal from one calibrated one, whats wrong with it? if you do that with a stable voltage and by voltage divider measurement using the linearity of the 3458A, you end up with pretty decent accuracies. I cannot comment on the 242, just did some quick checks some time ago and my quick assessment then was it is worse/not better than the 3458a method. Gesendet: Mittwoch, 09. Juli 2014 um 16:35 Uhr Von: Todd Micallef tmical...@gmail.com An: Discussion of precise voltage measurement volt-nuts@febo.com Betreff: Re: [volt-nuts] AC Voltage Measurement Standards I would like to know more about your setup. Which source(s) are you using for the input and which nanovoltmeter(s) are you using to transfer the 10V TVC to your other converters? I remember you asking on PMEL forum about the accuracy of using a 34420A nanovoltmeter. I did not see a response as to whether you opted for an alternative like Keithley 2182(A) or a low noise preamplifier connected to a 3458A. I have done some reading about how NIST transfers their calibrations using two TVC's in parallel and I am guessing that is what you are doing. http://www.nist.gov/pml/div684/acdc/tcs.cfm To transfer the accuracy up/down to other TVC's at different rated voltages appears to be a difficult task since they typically need at least half the rated max voltage to be within spec. It would be similar to starting with a SR104 standard and transferring its value through a set of SR1010 and SR1050 resistors using an ESI 242. I have a few AC sources, and I would like to be able to verify my TVC's without sending all of them out for cal. Ballantine quoted $600+ per TVC and I haven't checked what Fluke would charge for each A55. Todd 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. ___ 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.
Re: [volt-nuts] AC Voltage Measurement Standards
in a nutshell, what i am doing is that I first establish the dc (+/-) output of the ref. TVC at nominal and then determine the ac voltage from a precision, highly linear (datron 4808) ac source that generates that default output voltage at the key frequencies. that establishes a set of ac voltage settings. for these the deviations of the TVC are known from the calibration. then I do the same with the TVC to be calibrated. (factor of 2 nom. voltage is important to stay within allowable range). that way you can link both. sure, sending all to cal is more precise, if you get the right lab at least, but also very expensive. would sure be interested in your tech paper Gesendet: Donnerstag, 10. Juli 2014 um 13:27 Uhr Von: Stephen Grady grady.st...@gmail.com An: 'Discussion of precise voltage measurement' volt-nuts@febo.com Betreff: Re: [volt-nuts] AC Voltage Measurement Standards Todd and anyone else would is interested, Measuring a Thermal Converter against another Thermal Converter is a bit of a black art. The main problem is thermal converters are a square law device that is if you change the input voltage by a factor of 2 the output voltage will change by a factor of approximately 4. Now I say approximately because for most thermal converters like the Fluke 540B, A55, Ballantine and Holts the actual factor can be anywhere from 1.4 to 1.8 due to losses in the thermal converter. In the literature you often see this factor refer to as the N factors. Each thermal converter will have its own N factor which must be measured to make sense of the measurements. It even becomes more difficult in that the AC-DC difference of a thermal converter is defined as (Vac-Vdc)/Vdc where Vac and Vdc are the inputs to a thermal converter which give an equal output from the converter. Also Vdc is the mean of the forward and reverse DC voltages. The problem is that when you have two converters connected in parallel you cannot balance both converters AC and DC inputs to produce equal voltage out of the converters at the same time because each converter has its own AC-DC difference and its own N factor. It anyone is interested I can send them a technical paper that describes this process and the appropriate math to use but I cannot send it to the list due to copyright issues. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Todd Micallef Sent: Thursday, 10 July 2014 2:36 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] AC Voltage Measurement Standards I would like to know more about your setup. Which source(s) are you using for the input and which nanovoltmeter(s) are you using to transfer the 10V TVC to your other converters? I remember you asking on PMEL forum about the accuracy of using a 34420A nanovoltmeter. I did not see a response as to whether you opted for an alternative like Keithley 2182(A) or a low noise preamplifier connected to a 3458A. I have done some reading about how NIST transfers their calibrations using two TVC's in parallel and I am guessing that is what you are doing. http://www.nist.gov/pml/div684/acdc/tcs.cfm To transfer the accuracy up/down to other TVC's at different rated voltages appears to be a difficult task since they typically need at least half the rated max voltage to be within spec. It would be similar to starting with a SR104 standard and transferring its value through a set of SR1010 and SR1050 resistors using an ESI 242. I have a few AC sources, and I would like to be able to verify my TVC's without sending all of them out for cal. Ballantine quoted $600+ per TVC and I haven't checked what Fluke would charge for each A55. Todd 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. ___ 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. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ volt-nuts
Re: [volt-nuts] AC Voltage Measurement Standards
The ultimate AC standard would be NIST's AC Josephson junction array. Sam Benz and his team continue to make advances, pushing the accuracy and output level. They have also substantially reduced the needed electronics placing much of the peripheral electronics in a custom built two-U enclosure. NIST has also recently introduced a fully programmable JJA that automates most of the set up and operation. It won't be long before we need 10 1/2 digit DMM's Cheers; Thomas Knox From: acb...@gmx.de To: volt-nuts@febo.com Date: Fri, 11 Jul 2014 01:13:44 +0200 Subject: Re: [volt-nuts] AC Voltage Measurement Standards in a nutshell, what i am doing is that I first establish the dc (+/-) output of the ref. TVC at nominal and then determine the ac voltage from a precision, highly linear (datron 4808) ac source that generates that default output voltage at the key frequencies. that establishes a set of ac voltage settings. for these the deviations of the TVC are known from the calibration. then I do the same with the TVC to be calibrated. (factor of 2 nom. voltage is important to stay within allowable range). that way you can link both. sure, sending all to cal is more precise, if you get the right lab at least, but also very expensive. would sure be interested in your tech paper Gesendet: Donnerstag, 10. Juli 2014 um 13:27 Uhr Von: Stephen Grady grady.st...@gmail.com An: 'Discussion of precise voltage measurement' volt-nuts@febo.com Betreff: Re: [volt-nuts] AC Voltage Measurement Standards Todd and anyone else would is interested, Measuring a Thermal Converter against another Thermal Converter is a bit of a black art. The main problem is thermal converters are a square law device that is if you change the input voltage by a factor of 2 the output voltage will change by a factor of approximately 4. Now I say approximately because for most thermal converters like the Fluke 540B, A55, Ballantine and Holts the actual factor can be anywhere from 1.4 to 1.8 due to losses in the thermal converter. In the literature you often see this factor refer to as the N factors. Each thermal converter will have its own N factor which must be measured to make sense of the measurements. It even becomes more difficult in that the AC-DC difference of a thermal converter is defined as (Vac-Vdc)/Vdc where Vac and Vdc are the inputs to a thermal converter which give an equal output from the converter. Also Vdc is the mean of the forward and reverse DC voltages. The problem is that when you have two converters connected in parallel you cannot balance both converters AC and DC inputs to produce equal voltage out of the converters at the same time because each converter has its own AC-DC difference and its own N factor. It anyone is interested I can send them a technical paper that describes this process and the appropriate math to use but I cannot send it to the list due to copyright issues. Kind Regards, Stephen Grady Sydney Australia -Original Message- From: volt-nuts-boun...@febo.com [mailto:volt-nuts-boun...@febo.com] On Behalf Of Todd Micallef Sent: Thursday, 10 July 2014 2:36 AM To: Discussion of precise voltage measurement Subject: Re: [volt-nuts] AC Voltage Measurement Standards I would like to know more about your setup. Which source(s) are you using for the input and which nanovoltmeter(s) are you using to transfer the 10V TVC to your other converters? I remember you asking on PMEL forum about the accuracy of using a 34420A nanovoltmeter. I did not see a response as to whether you opted for an alternative like Keithley 2182(A) or a low noise preamplifier connected to a 3458A. I have done some reading about how NIST transfers their calibrations using two TVC's in parallel and I am guessing that is what you are doing. http://www.nist.gov/pml/div684/acdc/tcs.cfm To transfer the accuracy up/down to other TVC's at different rated voltages appears to be a difficult task since they typically need at least half the rated max voltage to be within spec. It would be similar to starting with a SR104 standard and transferring its value through a set of SR1010 and SR1050 resistors using an ESI 242. I have a few AC sources, and I would like to be able to verify my TVC's without sending all of them out for cal. Ballantine quoted $600+ per TVC and I haven't checked what Fluke would charge for each A55. Todd 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
Re: [volt-nuts] AC Voltage Measurement Standards
The remark about calibrating the resistors was merely an example of how I thought you may have been transferring the calibration of the 10V TVC. My first thought was that you compared the 10V TVC to the next closest model at fixed points. The inter-comparison would then continue from that model to the next value down (or up). I had a hard time trying to understand how that could be accurate, and the thought of using a ratio transformer didn't cross my mind. Thanks for the explanation. I can see how the costs of calibrating a TVC can be so high. I am guessing few labs possess the equipment to calibrate them and places like Ballantine probably use NIST for their cals. Todd as far as your comment re. calibrating a set of resistor cal from one calibrated one, whats wrong with it? if you do that with a stable voltage and by voltage divider measurement using the linearity of the 3458A, you end up with pretty decent accuracies. I cannot comment on the 242, just did some quick checks some time ago and my quick assessment then was it is worse/not better than the 3458a method. ___ 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] Need info on LN 4214 temp vs resistance plot..
I'm guessing that the 4214 10K standard has a resistance curve that peaks around 73F??? I've searched for old pix of data and can't find any. The 4214 I got this week had no old, original data with it in its box. Over the past few years there have been some resistance standards sold on fleabay with pictures of temp vs. resistor value charts pasted on the top cover. They may not have been 4214s, though. I also just discovered that fleabay drops its pix on items sold past a certain date. So, volt-nuts any help??? Alphas, Betas, charts? Willy ___ 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.
