【正文】 nEpEpiii????? BiiBiiiEnEpEpEC ??????? ???????1/1/ECECCECBCiiiiiiiii?The Base transport factor iC=BiEp EpEnB iBii )1( ???? It remains to be shown that the collector current iC can be controlled by variations in the small current iB. ? In fact, we can show from space charge neutrality arguments that iB can indeed be used to determine the magnitude of iC. Assume the emitter injection efficiency ?=1。)()()(。)()(??????Diffusion currents equations with pbpbpbPbLWLWCLWELpWbLWLpWbECeepepCeeeppC?????????????21)()()()0()()()(121221pbpbpnpnLWLWppbnpCppnpEpnnpnpLxLxneCeCLDqAWxIICCLDqAxIIdxxpdq A DxIeCeCxp?????????????????????????????????????????????????????????pbCEppBpbpbCEppCEBpbCpbEppCpbCpbEppEpLWppLDqAILWhLWc t n hppLDqAIIILWc t n hpLWhpLDqAILWhpLWc t n hpLDqAI2t a n h)(c s c)()c s c()c s c()()()()()()t an h ()(1)(s ec2)()(1)(c s c h2)(xshxchxct n hxchxshxxchxheexchxshxeexshxxxx??????????)1()1(//??????kTqVnCkTqVnECBEBeppeppWhere, Example 72 (a)Find the expression for the current I for the transistor connection shown if γ=1. (b)How does the current I divide between the base lead and the collector lead? P+ P+ n C E B I V + pbEpppbCpbEppCLWhpLDqALWct n hpLWhpLDqAIc s c)c s c(??????)1( / ??? kTqVnC CBepp 0?? CpSolutions: Since VCB=0, pbEpppbCEppBLWpLDqALWppLDqAI2t an h2t an h)(??????????????pbEpppbCpbEppEpLWc t n hpLDqALWhpLW