CHAPTER V 



TRANSDUCERS 



Research on Magnetostriction Transducers. 



As is Inevitable in the hurry of war, much of the scien- 

 tific work devoted to the production of new tools for subsur- 

 face warfare Involved the type of research that is commonly 

 called developmental^ rather than the type which may be called 

 fundamental or basic „ Yet considerable research of the latter 

 sort was done In the field of transducer development . Trans- 

 ducers were required in a wide variety. Sonar devices were 

 made for listening, where their function was to make possible 

 the perception of noise-making objects such as a ship's pro- 

 peller or the enemy's sonar gear. They were made for echo- 

 ranging to detect the presence of submarines and other objects; 

 for sounding to measure the depth of the water; for masking, 

 to interfere with the performance cf enemy sonar; and for de- 

 coyingj to make sounds and noises to confuse and mislead the 

 enemy o 



Although the word "transducer" by its Latin derivation 

 may properly be used to describe any device which converts 

 energy of one type to energy of some other type^ in this 

 volume "transducer" is used to describe the device which con- 

 verts electrical energy into acoustical energy and vice versa. 

 This conversion can be accomplished in several ways: electro- 

 dynamicallyj as in the convention radio loudspeaker; by the 

 magnetostriction effect; and by the piezoelectric effect, 



A substantial program of basic physical research in mag- 

 netostriction was conducted by three of the Division 6 con- 

 tractors in parallel with a program for the development of 

 transducers for experimental and service use , These contrac- 

 tors included the Bell Telephone Laboratories, the Harvard 

 Underwater Sound Laboratory and the Columbia University 

 Division of War Research Laboratory at New London. As a 

 result of this research effort s the fundamental scientific 

 base for further development work in magnetostriction has 

 been broadened and strengthened rather than restricted by the 

 work concentrated on applications useful in subsurface warfare. 



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