Masters Theses


"In the past 10 years, magnetic amplifiers have received much attention in many different fields of engineering. Although the principles of this amplifier have been known since 1915, it has been forced into the background by the development of the vacuum tube amplifier, the need of better core material and better dry disk rectifiers.

The basic magnetic amplifier, or saturable reactor, is nothing more than an iron core reactance coil whose a-c impedance is controlled by a d-c premagnetization of the core. This d-c premagnetization may be obtained in a number of ways, the simplest of which is a separate d-c source.

The name amplifier applies because, by a small variation of the d-c control current, larger variation of the a-c output current may be obtained. The ratio of these currents is known as current gain and is a very important quantity in the study of magnetic amplifiers. It will be shown that with certain refinements, namely that of feedback, it is possible to greatly increase this gain.

The main purpose of this thesis is to analyze a series type magnetic amplifier in two different ways and then to compare these analyses.

More specifically, a half wave magnetic amplifier circuit will first be considered in which an attempt is made to consider all aspects of the problem. This analysis will be shown to be impractical because of mathematical complications and will then be abandoned. A new approach to the problem with certain simplifying assumptions will be made that will lead to an approximate mathematical solution.

A full-wave series magnetic circuit will then be analyzed assuming a power series approximation of the B-H characteristic. This type of approach has its shortcomings, however, but serves quite nicely to yield information which other approaches fail to give.

Finally, an approach to the problem will be made by assuming straight line magnetization curves. This analysis gives quite a lot of useful information as will be shown later in this thesis. These analyses will then be compared as to accuracy of results, assumptions made, and validity of the initial assumptions.

A short discussion on magnetic amplifiers used as mixers and as audio amplifiers will be given"--Introduction, pages 1-2.


Skitek, G. G. (Gabriel G.)


Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering


Missouri School of Mines and Metallurgy

Publication Date



v, 64 pages

Note about bibliography

Includes bibliographical references (page 63).


© 1952 Wiley Talley Ruhl, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Magnetic amplifiers
Magnetic flux -- Mathematical models
Magnetic fields -- Mathematical models

Thesis Number

T 1026

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