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AA-35 Zoom Capacitance Accuracy

#AA-35-ZOOM

David Dybas All Messages By This Member #610 Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Alex RigExpert Member Profile All Messages By This Member #612 开云体育 Dear Dave, It is necessary to measure the capacitance of the capacitors (or the inductance of the coils) at the frequency where the value of the active resistance is about 50 ohms. That is, the algorithm is as follows: - connect the capacitor to the analyzer - start the R X measurement in the entire range (button 5) - move the cursor to the value of R= 50 ohms in the chart. - press button 8 and get the capacity value. Regards, Alex 29.04.2021 00:10, David Dybas via groups.io пишет: toggle quoted message Show quoted text Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Ken All Messages By This Member #613 It might depend on the capacity of the units compared to the fixture used to connect them to the analyzer. The fixture's capacitance would be included in the measured capacitance unless calibrated out. You should find a method to do the Open Short Load (OSL) calibration at the fixture Unit Under Test (UUT) terminals.? Sent From My Desktop Via EMClient. toggle quoted message Show quoted text ------ Original Message ------ From: "David Dybas via groups.io" <Dd92251@...> To: [email protected] Sent: 4/28/2021 2:10:10 PM Subject: [RigExpert Family] AA-35 Zoom Capacitance Accuracy #AA-35-ZOOM Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
David Dybas All Messages By This Member #615 I dont see any means for doing an OSL calibration of this model unit. But I will keep searching. BTW that is a great idea ...I use that approach with my Array Solutions VNA. toggle quoted message Show quoted text On Apr 29, 2021 12:54 AM, Ken <ko6no@...> wrote: It might depend on the capacity of the units compared to the fixture used to connect them to the analyzer. The fixture's capacitance would be included in the measured capacitance unless calibrated out. You should find a method to do the Open Short Load (OSL) calibration at the fixture Unit Under Test (UUT) terminals.? Sent From My Desktop Via EMClient. ------ Original Message ------ From: "David Dybas via groups.io" <Dd92251@...> To: [email protected] Sent: 4/28/2021 2:10:10 PM Subject: [RigExpert Family] AA-35 Zoom Capacitance Accuracy #AA-35-ZOOM Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Alex RigExpert Member Profile All Messages By This Member #616 开云体育 Hello, AA-35 Zoom does not have a built-in OSL calibration function. 29.04.2021 19:52, David Dybas via groups.io пишет: toggle quoted message Show quoted text I dont see any means for doing an OSL calibration of this model unit. But I will keep searching. BTW that is a great idea ...I use that approach with my Array Solutions VNA. On Apr 29, 2021 12:54 AM, Ken <ko6no@...> wrote: It might depend on the capacity of the units compared to the fixture used to connect them to the analyzer. The fixture's capacitance would be included in the measured capacitance unless calibrated out. You should find a method to do the Open Short Load (OSL) calibration at the fixture Unit Under Test (UUT) terminals.? Sent From My Desktop Via EMClient. ------ Original Message ------ From: "David Dybas via groups.io" <Dd92251@...> To: [email protected] Sent: 4/28/2021 2:10:10 PM Subject: [RigExpert Family] AA-35 Zoom Capacitance Accuracy #AA-35-ZOOM Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Tom Parkinson All Messages By This Member #617 AA-55ZOOM and up -? toggle quoted message Show quoted text On Thu, Apr 29, 2021 at 1:30 PM David Dybas via <Dd92251=[email protected]> wrote: I dont see any means for doing an OSL calibration of this model unit. But I will keep searching. BTW that is a great idea ...I use that approach with my Array Solutions VNA. On Apr 29, 2021 12:54 AM, Ken <ko6no@...> wrote: It might depend on the capacity of the units compared to the fixture used to connect them to the analyzer. The fixture's capacitance would be included in the measured capacitance unless calibrated out. You should find a method to do the Open Short Load (OSL) calibration at the fixture Unit Under Test (UUT) terminals.? Sent From My Desktop Via EMClient. ------ Original Message ------ From: "David Dybas via " <Dd92251@...> To: [email protected] Sent: 4/28/2021 2:10:10 PM Subject: [RigExpert Family] AA-35 Zoom Capacitance Accuracy #AA-35-ZOOM Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Alex RigExpert Member Profile All Messages By This Member #618 开云体育 Good video about this topic: 29.04.2021 22:00, Tom Parkinson пишет: toggle quoted message Show quoted text AA-55ZOOM and up -? On Thu, Apr 29, 2021 at 1:30 PM David Dybas via <Dd92251=[email protected]> wrote: I dont see any means for doing an OSL calibration of this model unit. But I will keep searching. BTW that is a great idea ...I use that approach with my Array Solutions VNA. On Apr 29, 2021 12:54 AM, Ken <ko6no@...> wrote: It might depend on the capacity of the units compared to the fixture used to connect them to the analyzer. The fixture's capacitance would be included in the measured capacitance unless calibrated out. You should find a method to do the Open Short Load (OSL) calibration at the fixture Unit Under Test (UUT) terminals.? Sent From My Desktop Via EMClient. ------ Original Message ------ From: "David Dybas via " <Dd92251@...> To: [email protected] Sent: 4/28/2021 2:10:10 PM Subject: [RigExpert Family] AA-35 Zoom Capacitance Accuracy #AA-35-ZOOM Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? Best Wishes Dave Dybas
Doug VE7DXK All Messages By This Member #622 On Wed, Apr 28, 2021 at 02:14 PM, David Dybas wrote: Hi All, I am measuring 1% tolerance Silvered-Mica Capacitors which I purchased new from a large supply house.? ?When I use the AA-35 to measure these capacitors, of various capacitances,? the AA-35 gives me measured values that are about 20% higher than the Capacitors marked value.? ?I do not suspect the capacitors to be mis-marked.? ?What can I expect for the accuracy of the AA-35 ?? ? ?Is there a particular frequency to measure the capacitors to get the best and most accurate measurement ?? ? ? ?I have another brand of VNA that gives me better, but still not perfect measurement values.? ?Does anyone have information regarding my problem ? You need a proper test jig in order to measure components accurately.? I wrote a post on this topic some time ago.?? /g/RigExpert-Family/message/352
Doug VE7DXK All Messages By This Member #623 David, Another thing to keep in mind is the inductance of the leads on your capacitor.? It is about 5 nanohenries (nH) per cm or 13 nH per inch. This has a considerable effect depending on what frequency you measure the component.? ? This was posted by a guy on Facebook using his NanoVNA.? ? I did a similar plot of a 10 pF cap using my AA-55 Zoom and AntScope2 .? Results were exported from AntScope2 as a CSV file and plotted in a spreadsheet.? ?Note how you you need to be in a reasonable reactance range to get a decent estimate of capacitance. ?

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