Can't measure capacitors!

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sm7etw
Posts: 2
Joined: Mon Sep 26, 2016 1:31 am

Can't measure capacitors!

Post by sm7etw » Mon Sep 26, 2016 9:45 pm

Hi Dan

Using latest version from Google play.

I have tried measuring capacitors but can't get it to work.
I select XLC, and then C.
Put a capacitor (470 pF) via a adapter to the DUT connector.
Nothing happens, I then hit run and get some diagram but no values for the capacitors.

What am I doing wrong ?

73 Jan SM7ETW

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yo3ggx
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Joined: Wed Aug 15, 2012 8:30 pm

Re: Can't measure capacitors!

Post by yo3ggx » Mon Sep 26, 2016 10:03 pm

Hi Jan,

What is your miniVNA model?
You need to run a capture in Reflection mode with XLC overlay activated and C selected in order to measure the capacity.
Do you get any values in the data fields after a capture?
Please post a screenshot after a capture, with your 470pF capacitor connected to the DUT connector.

Thank you.
73 Dan YO3GGX

sm7etw
Posts: 2
Joined: Mon Sep 26, 2016 1:31 am

Re: Can't measure capacitors!

Post by sm7etw » Mon Sep 26, 2016 10:29 pm

Minivna std

reflection selected then M then XLC toogle, the screen with xtal l and c shown.
Select C it gets yellow, select run it says receiving data, the overlay disappears a graph comes with phase Rs and XS.
screenshot attached...
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yo3ggx
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Joined: Wed Aug 15, 2012 8:30 pm

Re: Can't measure capacitors!

Post by yo3ggx » Mon Sep 26, 2016 11:02 pm

The overlay must not disappear after a capture, this must be a bug in your particular configuration. Anyway, miniVNA standard is not able to provide the sign of the reactance (Xs) so is not suitable for XLC mode (implemented in BlueVNA), as the resonance frequency is determined by the Xs pass through 0 (with sign change).

I don't have a miniVNA Std here to test this now, but I will do it as soon as possible.

I'm really sorry for that.
73 Dan YO3GGX

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