428 



THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1952 



manding that alpha, as a function of /« , go through a transition from a 

 negUgible vahie (at small negative le) to a value well in excess of unity 

 (at a correspondingly small positive value of /«) and maintain its value 

 well in excess of unity at large values of /« , conditions (b) and (c) can 

 be met. 



In Fig. 20 are given the characteristic specifications which must be 

 met by the M1689 bead type switching transistor now under develop- 

 ment. With these kinds of limits, circuit users find it possible to inter- 

 change such M1689 units in various pulse circuits and obtain ovei-all 

 circuit behavior reproducible to the order of about dz2 db. 



Fig. 18 — Idealized collector characteristics. 



0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 

 EMITTER CURRENT, If , IN MILLIAMPERES 



Fig. 19 — Effective alpha characteristic. 



