NAME___________________________________________________________
Find:
ß = (we/wb)(un/up)(NE/NAB)Let Ne = Neff = 1018
In the base where doping is 1017 , un = 1200
In the emitter where doping is 5x1019 , up = 100
ß = (we/wb)(un/up)(Neff/NAB) = (1.5/1)(1200/100)(1018/1017 = 180
where tbb = wb2/(2 Dn) = 10-8/(2*31) = 0.16 nSec.Dn = VT un = 0.0259 * 1200
FT, the frequency at which the magnitude of beta is one___FT = 1/(2 pi tbb) = 995 MHz__