Page 45 - 30105-2003 การวิเคราะห์วงจรอิเล็กทรอนิกส์ความถี่สูง

37
1. !!" # $
%&

Q 1 V CC = 10 V

1.29 - ( H / %$ &!
FE

1.6 - ก 1.29 - ( H &
V R C = 6 V,V R B = 3 V;
FE
V R 6
=
9 + H FE = C × 100 = × 100 200
V R 3
B

H = == = 200
FE
1.4.3.4 P ! ก ก % % (F

)
T
8' &ก ก0, , $ + %$ 0 & . 8' / ! /

0

ก ( ! ก0, , $ & . * + 0! / ก ( '0,' ' &+'
& . 1 " -0 -

,, $ $!&! ก
F = B β
F
W
T
&
- ก B ≈ F
β
W
F = F β
β
F
T
0
&
- ก F & . * + 0! / ก ( '0, ' ' &+'
& . 0.707 & / ! /
β
ก ( ! -( ก
β ( o F β ) = 0.707β
F
" β ( o F β )
0! / ก ( '0,/ F
β

0 0 F = F β F (1.5)
β
T
β ( o F β ) = 0.707β F

1.7 %$ &! F = 6.5 GH , H FE = 120;- ( / F '( β ( o F β )
z
β
T
9 + H FE = β
F
×
F 6.5 10 9
- ก ก (1.5) F = T = = 54.166 MHz
β
β
F 120
)
β ( o F β ) = (0.707 β = 0.707 120 84.84 85
≅
=
×
F
≅
≅ ≅ ≅

F = == = 54.166 MHz, β ββ β ( o F β ββ β ) = = = = 84.84 85;
β ββ β
ก

ก
ก