
Ampliers: Basic BJT Congurations
411
So, it has been conveniently separated into two terms
/
vBJT
and
vi
,
The term A
vBJT
can be considered the voltage gain owing to the BJT
itself, because of the ratio of its output and input voltages. The term
,
will
reduce the overall voltage gain A
v
because it takes into account the voltage divider
effect owing to the input loop, as we will see, so this term furnishes an attenua-
tion effect.
A
vBJT
v
v
vBJT
c
b
def
The base and collector voltages can be written as
vv vv Ri vR
bbeebe Ee be Eb c
=+=+ =+ +
vv vv Ri vR
cceece Ee ce Eb c
=+=+ =+ +
and from Equation II C.E.
v
h
ihi
ce
oe
eb