4KH BELL SYSTEM TEC/LXICAL JOl K\AL 



ii„ , lip = equilibrium densities of electrons in ;/- and />-regions 



f) = density of holes 



p„ , p,, = equilibrium densities of holes in //- and /"-regions 



pt) = d-c. component of non-equilibrium hole density (4.3) 



pi e.\p(/co/) == a-c. component of non-equilibrium hole density (4.3) 



P = total number per unit area of holes in specimen (2.35) 



(/ = electronic charge {q = \q \) 



Q — qP = total charge per unit area (2.39) 



r = recombination coefficient for holes and electrons (3.1) 



R — resistance of unit area 



Ka = resistance of unit area obtained by integrating conductivity (3.10), 



Append i.\ I 

 R\ = effective series resistance, discussed in connection with (3.13) 

 .y = rate of recombination per unit area of surface per unit hole density. 



Appendix V 

 S ^ susceptance per unit area (imaginary i)art of admittance) 

 S,, , S„ , 5ras for .fs. 

 / = time 



T = temperature in °K 

 T = subscript for transition region 

 I, = cpP/kT (2.9), q{4^ - <fx):kT (2.32), Appendix VII 

 CO and ric'"' = d-c. and a-c. components of voltage applied in forward direc- 

 tion (4.2) 

 ir = width of space charge region in abrupt junction, Section 2.4 

 w — half thickness of »-region or transistor base of Sections 5 and 6. 



IV = half width of square rod in Appendbc V. 



.V = coordinate perpendicular to plane of junction 



V, :; = transverse coordinates. Appendix V 



y = reduced length (2.17), Appendix VII 



a = current gain factor in transistor (6.4) 



a = parameter in Appendix III and VI 



a,j = parameter in Appendix \' 



fi, = pir.imeter in Appendix \' 



7 = parameter in Appendices II, IV and \'II 



e = syml)ol for emitter Section 6 



0, = ^ ,'.v Appendix \' 



;> = (l:,.'lectric constant 



^ = mobility of a hole (6/x — mobility of electron) 



V = rates of recombination etc., Appendix \'I 

 p = charge density (2.1) 



a = conductivity 



I 



