Page 180 - 30105-2003 การวิเคราะห์วงจรอิเล็กทรอนิกส์ความถี่สูง

172
4.

R = R R r + R )
EP E 2 ( d 2 L
! ก R

1
ก
5( & 4%
! 0 # ก - R
0
2 E
r
R EP = R ( d 2 + R L )
E
R E ( d + R L )
r
R EP = 2
( R + r d + R L )
E
2
E = I r + I r + I (β + 1)R
i b bb′ b b e ′ b F EP
E
I = i
b
r bb′ + r b e ′ + (β + 1)R EP
F
E i E i {r bb′ + r b e ′ + (β + 1)R EP }
F
R i (0- ) = I b = E i
π
R i (0- ) = r bb′ + r b e ′ + (β + 1)R EP
π
F
% & R = r + r + (β + ) 1 R (4.11a)
π
i (0- ) bb′ b e ′ F EP
R in (0- ) R i (0- )
π
π
r bb′ D 1
B b′ C A K
I b I c
r V g V
R g b e ′ b e ′ m b e ′ R C R 1
E g E i R BB D 2
I E A K
e
R EP r d I d
π
R E R 2 2 2 R L V o (0- )

1 4.7 . % 4==D ก (. 5 -
ก5 , (0- ) # 1 4.5
π

!
0 (
# - ก -ก %* , (0- )
R in (0- ) π
π
R R 2
B
1 B
R =
BB
R B 1 + R B 2
R
R BB i (0- )
π

ก R in (0- ) = ( R BB R i (0- ) ) =
π
π
R BB + R i (0- )
π
R R (0- )
π
BB i
% & R = (4.11b)
π
in (0- )
R BB + R i (0- )
π

*& 4.10 ก 1 4.7 (
R i (0- ) .5( R in (0- )
π
π
+ , ก
ก (4.11a) R i (0- ) = r bb′ + r b e ′ + (β + ) 1 R
π
EP
F
ก

ก
ก