p-,i Jl\\CnO\S l.\ SKMICO.XDLCTORS 



473 



For icvXp large, the junctions do not interact and the hyperbolic coeflicient 

 becomes unity and Ii, = —[f,o(ft) + ^poi'fr)]. 



EMITTER 



BASE 



COLLECTOR 



(a) 



n+^f 





(b) 



DISTANCE THROUGH SAMPLE , X *- 



Fig. 11 — p-ii-p transistor. 



(a) Thermal erjuilibrium. 



(b) Operating condition. 



If (fc is several volts negative, so that I ,x){^c) has its saturation value 

 I ,„ (see (4.11) and (4.20)), then the ratio -hi, '81, = a has the vakie 



5h 

 '81, 



csch -z— - 



-? = sech — - 



2w Lj, 



(6.4) 



coth 



Lr 



l-"or (2ic/Lp) = 0.5, 1, 2 respectively, a = O.cS^, 0.65, 0.27. Since the output 

 impedance R22 will be very high when >pc is in the reverse direction, and the 



