Ferrite Toroid Research Articles

Uniform Rotational Flux Reversal of Ferrite Toroids

A model is presented for the high speed uniform rotational flux reversal of ferrite toroids. The magnetization is uniform in the sense that the components of magnetization in a cylindrical coordinate system are independent of position. Analysis of the model, to a very good approximation, leads to results identical with those obtained from uniform rotation in isotropic thin films. The minimum switching coefficient predicted by this model is 0.005 oe μsec. Experimental confirmation of a high speed switching mode in ferrite toroids is given. A toroid with a wire loop embedded in it was used to induce the proposed flux configuration. The switching coefficient and the extrapolated threshold field associated with the high speed mode have been found to decrease with increasing temperature.

Some Broad-Band Transformers

Several transmission line transformers are described which have bandwidth ratios as high as 20,000:1 in the frequency range of a few tens of kilocycles to over a thousand megacycles. Experimental data are presented on both transformers and hybrid circuits. Typical applications are: interstage transformers for broad-band amplifiers; baluns for driving balanced antennas and broad-band oscilloscopes; and hybrids for use in pulse reflectometers, balanced modulators, etc. These transformers can be made quite small. Excellent transformers have been made using ferrite toroids having an outside diameter of 0.080 inch.

Uniform Rotational Flux Reversal of Ferrite Toroids

A model is presented for the high-speed uniform rotational reversal of ferrite toroids. This model eliminates the prohibitively high demagnetizing energy usually associated with uniform rotation in toroids. Analysis of the model, to a very good approximation, leads to results identical with those obtained from uniform rotation in isotropic thin films. Experimental confirmation of a high-speed switching mode in ferrite toroids is given.

Recent Advances in Magnetic Devices for Computers

Major advances in computer technology have been made by the use of magnetic devices. The speed of operation, storage capacity, and reliability of computers has been significantly increased by the development of the memory core. The present paper will describe some of the newer magnetic elements which may replace ferrite toroids in memory matrices. Ferrite materials are being used as sheets and multiaperture devices. The sheets show great promise in achieving a cost reduction. The multiaperture devices in memory applications offer the advantages of increased speeds, a wider operating temperature range, and nondestructive readout. The ferromagnetic materials are used in the form of thin films and wrapped wire. The films are capable of increased switching speeds at nominal current drives. The use of magnetic wire as a storage element offers new fabrication technology, a wider operating temperature range, and new functional structures. A comparison is made to highlight the device characteristics of the various structures.