Can't measure capacitors!

Here we will discuss only topics related to the miniVNA Android application
Post Reply
sm7etw
Posts: 2
Joined: Mon Sep 26, 2016 1:31 am

Can't measure capacitors!

Post by sm7etw »

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
User avatar
yo3ggx
Site Admin
Posts: 753
Joined: Wed Aug 15, 2012 8:30 pm
Location: Bucharest, România
Contact:

Re: Can't measure capacitors!

Post by yo3ggx »

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 »

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...
Attachments
miniVNA-0926162120.png
miniVNA-0926162120.png (81.25 KiB) Viewed 3840 times
User avatar
yo3ggx
Site Admin
Posts: 753
Joined: Wed Aug 15, 2012 8:30 pm
Location: Bucharest, România
Contact:

Re: Can't measure capacitors!

Post by yo3ggx »

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
Post Reply