Peak an inductor actively?

I want to peak an LC circuit as the load changes. It's < 30 KHz and the inductor is approx 20 mH.
I've seen some patents for electrically-controlled inductors (one winding is
the control winding) which changes the permeability of the core. But I've not found any such designs used or offerings on-line.
I would appreciate any constructive suggestions how I might go about this.
Janey
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Janey wrote:

Not an inductor but use a gyrator? <http://en.wikipedia.org/wiki/Gyrator
--
Adrian C

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Janey wrote:

go read some ancient books on magnetic amplifiers; Geyger & Storm are both very good.
this stuff is old. so old that it hasnt been mentioned in universities for decades (except for using mag-amp post-regulators on smps), so I wouldnt owrry about any patents.
Cheers Terry
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--
http://www.google.com/search?hl=en&q=saturable+reactor

JF

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What's your application?

JF

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"Janey"

** Be a hell of a lot easier to vary the drive frequency to bring the LC circuit into resonance.
Just needs a detector to indicate when the voltage and current are in phase.
..... Phil
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If that were the goal, yes. But I want to peak a given frequency.

How would one go about this detection?
J.
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--

Easiest way: (View in Courier:)

29KhZ
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On Wed, 09 Apr 2008 11:54:37 -0500, John Fields

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PS:

Version 4
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The basics of designing a saturable reactor is:
1. wind a 3-winding inductor (or two 2-winding inductors) - design for a uH/mH value greater than your greatest need 2. wire the "business" windings in series 3. apply a DC voltage to the control winding(s) and adjust such that the sum inductance in the main windings reduces and approaches your target.
The inductance will be maximum with minimum control voltage, and vice versa.
Is this right?
Janey
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