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From: Peter <occassionally-confused@nospam.co.uk>
Newsgroups: sci.electronics.design
Subject: Re: How to make an 8mH inductor which can handle 13V peak square wave without saturation
Date: Tue, 12 Mar 2024 12:59:22 +0000
Organization: A noiseless patient Spider
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Just an update.

I tested that 8mH coil from Mouser. Verified at 8mH with an LCR meter
and with the $500 micro tweezer thingy.

Doesn't work!! It behaves like it was 20mH or something like that. The
attenuation is way too high. But 8mH was the perfect value with that
funny milspec 0-10mH box I got off Ebay, which was heavy enough to
contain pretty big inductors.

So what is happening?

Must be something in the waveform which is buggering up the way these
inductors behave, in conjunction with the demodulation scheme used to
"decode" the LVDT position.

Maybe it is saturating, but saturation has the opposite effect: it
*lowers* the effective inductance.

So I bought a 2.5mH one from Mouser, again one which can do 1.5A or
so, and will try that, after the potting compound has gone off :)