
Principles of Analog Electronics
426
➜ The parameter
i
v
ob
c
cb
i
e
=
=
can often be negligible since it is related to the poor slope of the BJT’s output
characteristics within the active region.
The AC analysis will here be performed according to Figure 11.49 (the analysis
for Figure 11.50 is similar to that already performed in Section 11.5.2).
Before determining the circuit’s equations, it is useful to recall the formulas of
the h–parameter network, which are useful to model the AC behavior of the BJT
when it operates in C.B. conguration in the center of the forward-active region
(Section11.3.2):
vhihveqICB
ihihve
eb ib erbcb
cfbe ob cb
=+
=+
(...