
Principles of Analog Electronics
416
In addition, let us dene, as usual, R
12
= R
1
| |R
2
and R
EL
= R
E
| |R
L
In order to calculate the unknown values, we will use the two hybrid parameter
equations of the BJT in “c” subscripts:
vhihveqICC
ihihveq
bc ic brcec
efcb oc ec
=+
=+
(...)
(.III CC
)
The subscript “c” merely indicates that h–parameters are specic for a BJT used
in a common-collector amplier topology.
11.6.2.1
C.C. (C.C. Hybrid Parameters): Input Resistance
R
iBJT
v
i
iBJT
bc
def
The equation of the output voltage, v
ec
= –R
EL
i
e
, is substituted in
Equation II C.C. obtaining
−= +
v
R
hi hv
ec
fc bo
c
from which we nd the v
ec
expression and subs ...