400 BELL SYSTEM TECHNICAL JOURNAL 



So far on most counts the comparison is not too favorable but, as we said 

 before, it isn't fair to the baby. In addition there are a number of other 

 considerations which are secondary from the point of view of pure technique 

 but may be dominant from other points of view. Among favorable factors 

 here are: small size; low power drain; no standby power, but instant re- 

 sponse when needed; low heating effect when used in large numbers; and 

 ruggedness. 



The life of transistors should be fairly long on the basis of diode per- 

 formance, but the device is too new to permit definite statement. The 

 mechanical simplicity might well lead one to hope for low cost, but no 

 production figures are as yet available. 



In fine, even if Type A transistor performance does not excel all electron 

 tubes, it is still good enough for many applications and will be considerably 

 better in the future. 



Acknowledgement 



This survey is based on the work of many people, only a few of whom 

 have been mentioned in the text. The examples of circuits have not been 

 numerous or exhaustive, but rather have been used to illustrate the methods 

 adopted; these are general enough to be adapted to the solution of many 

 particular problems. 



