The Bell Sysleiu Teeliiiieal Journal 



Volume XXXI May 1952 Number 3 



COPYRIGHT 1952, AMERICAN TELEPHONE AND TELEGRAPH COMPANY 



Present Status of Transistor Development 



By J. A. MORTON 



(Manuscript received March 17, 1952) 



The invention of the transistor provided a simple, apparently rugged device 

 that could amplify — an ability in which the vacuum tube had long held a 

 monopoly. As with most new electron devices, however, a number of extremely 

 practical limitations had to be overcome before the transistor could be re- 

 garded as a practical circuit element. In particular: the reproducibility of 

 units was poor — units intended to be alike were not interchangeable in 

 circuits; the reliability was poor — in an uncomfortably large fraction of 

 units made, the characteristics changed suddenly and. inexplicably; and the 

 "designability" was poor — it was difflcidt to make devices to the wide range 

 of desirable characteristics needed in modem communications functions. 

 This paper describes the progress that has been made in reducing these 

 limitations and extending the range of performance and usefulness of tran- 

 sistors in communications systems. The conclusion is drawn that for some 

 system functions, particidarly those requiring extreme miniaturization in 

 space and power as w^ll as reliability with respect to life and ruggedness, 

 transistors promise important advantages. 



IXTRODUCTIOX 



When the transistor was announced not quite four years ago,- it was 

 felt that a new departure in communication techniques had come into 

 view. Here was a mechanically simple device Avhich could perform many 

 of the amplification functions over which the electron tube had long 

 held a near monopoly. The device was small, required no heater power, 

 and was potentially very rugged; moreover, it consisted of materials 

 which might be expected to last indefinitely long, and it did not appear 

 to be too complicated to make. 



However, as might be expected for a newly invented electron device, 

 the practical realization of these promises still required the overcoming 



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