Re: LF: Current Transformers (off topic, but expertise probably here)

[Alberto di Bene <dibene@usa.net>]

Andy wrote:

> BUT, and I don't know how to account for it,  there was a very significant
> non-linearity .  Testing over a range of currents from 0.2A RMS to 9A, the
> slope of the  Vout / Iin graph shifted by nearly a factor of 2.
>
> That says 'core saturation' to me,  but I don't see how that can be.   If
> the core is saturating with just 9V across a winding designed for 240V, it
> doesn't say a lot for the device in a PSU.   Should reducing the value of
> the  burden resistor help matters?
>  
Have you considered the possibility that for the material composing the 
core the ratio B/H is not a constant ? It could exhibit a change in 
value much before reaching the saturation point. But I am not an expert 
in metals, so take my words with a grain of salt...
73  Alberto  I2PHD