Browse Prior Art Database

Adjustable Inductors and Transformers

IP.com Disclosure Number: IPCOM000098963D
Original Publication Date: 1962-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Gunn, JB: AUTHOR

Abstract

A and B illustrate an infinitely variable inductor and a transformer, respectively. Both utilize two identical ferrite cup cores having loose windings in them. The ends of these are brought out through holes provided in the cup cores.

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Adjustable Inductors and Transformers

A and B illustrate an infinitely variable inductor and a transformer, respectively. Both utilize two identical ferrite cup cores having loose windings in them. The ends of these are brought out through holes provided in the cup cores.

A variable inductor (A) is made by using a loose winding W1 with one end brought out through a hole in each half-core 1. By clamping the cores together so that they are in magnetic contact, but still free to rotate, it is possible to vary the number of turns continuously over a certain range by a relative motion of the half cores. Thus, an infinitesimally variable inductor is realized having all the desirable properties of cup core construction. A number of other possibilities exist utilizing the A structure. By bringing both ends of one winding out through one core and the ends of the other out through both cores, as described, a transformer is obtained having very nearly unity coupling but having adjustable mutual inductance. As a variation, both windings can be brought out in the adjustable manner, but by winding them originally in opposite directions the number of turns on one may be increased as the number of turns on the other are decreased by the same amount, when the cores are rotated.

In the B structure, independent adjustment of a number of windings is obtained by interposing ferrite annuli between the outer opposing faces of the cup cores 1. The adjustable windings each have an end br...