Theory of superconductivity: by M. von Laue, translated by Lothar Meyer and William Band. 140 pages, diagrams, 16×24 cm. New York, Academic Press, Inc., 1952. Price, $4.00
✍ Scribed by William F. Love
- Publisher
- Elsevier Science
- Year
- 1952
- Tongue
- English
- Weight
- 153 KB
- Volume
- 254
- Category
- Article
- ISSN
- 0016-0032
No coin nor oath required. For personal study only.
✦ Synopsis
Price, $7.00. The subject of d-c. analog computers is treated very effectively by the authors who have used such devices and have perfected through experience ways and means of avoiding the common pitfalls inherent in their use. The book commences with an introduction to the subject, then guides the reader through chapters on Practical Setup Procedure, The Application of D-C. Analog Computers to Representative Practical Problems, Theory and Design of Linear Computing Elements, Operational Amplifiers and Networks, D-C. Amplifiers for Computer Applications, Multiplication and Function Generation, Auxiliary Circuits and Computer Operation, and The Design of Complete D-C. Analog-Computer Installations. An Appendix entitled Some Properties of Parallel-Feedback-Type Operational Amplifiers is followed by an excellent Bibliography and Author and Subject Index.
Those working with analog computers should benefit by reading this book, as well as those who have problems they feel might be solved by computers of this type. Actual procedures are explained in detail and step-by-step summaries are given after the discussions.
Computers of this type built around d-c. amplifiers and servo multipliers are capable of solving a large variety of problems. Their main use has been in solving sets of simultaneous differential equations which may have varying coefficients and even be non-linear. Provision may be made for initial conditions and the solution recorded for later study. Though considerable time is required for set-up, determination of scale factors and checking before the final solution is obtained, there are many advantages of using electron means instead of the desk-type computing machine. Once the problem is set up, for instance, the effect of a change in a coefficient may be seen at a glance merely by turning a knob. Such matters are presented by Korn and Korn in a manner that makes the reader feel some of the enthusiasm for the subject obviously shared by the authors.
Consideration is given to both advanced time-scale computers and those operating on a real time basis. Considerable attention is given to foolproof methods of establishing scale factors--a phase of the work the authors feel has caused the most errors by those using analog computers. The only place this reviewer can suggest any improvement in the text is in the subject of checking the computer prior to running the solution. A valuable means of checking block diagrams, scale factors and wiring is to replace the feedback capacitors of the d-c. amplifiers by the appropriate feedback resistors and after recording the output of each amplifier, compare the solution with that of the basic machine equations in which integrations have been replaced by sums.
Considerable progress has been made in the design of d-c. amplifiers in recent years and banks of them can be built using standard circuits or purchased from a number of manufacturers. With little more, the electronic engineer who has not yet entered this field may, with the use of Korns' book, find new adventure. Do~D B. HOUGHTON