LI GII HAY CHO MT BI TON
t in ỏp u = 120cos(100t + /4) V vo hai u on mch AB gm hai on AM v MB mc ni tip. AM
cha cun cm v MB cha in tr R. in ỏp hiu dng trờn AM v MB ln lt l 2010 V v 40 V. Khi
mc ni tip t in cú in dung 1/ mF vo on MB thỡ in ỏp hiu dng trờn AM l 2410 V. Tỡm R, Z
L
v vit biu thc dũng in khi cha cú t.
2 2 2
0
sin 60
1 2
cos 45
cos 60
2. . 3
2
sin 0,3 10
sin sin
L
L
R r
U AB
MB AB AM
R Z
U U AB
MB AB
AMB
AB AM






I
r
A
M B
40
60 2


20 10

( ) ( )
( ) ( ) ( )
( ) ( )
2 2
0
: 72 2 72
sin sin
2
: 12 14 72 12 14 11,69
2
6,16 4,11
3
C
C
C
L
L L
AN AM AN
AMN AN V AE NE V
U

r
L
U
r
I
r
A
M
B
0
45
β
24 10
sin 0,3 10
β
=
60 2
0
45
N
R
,L r
C
B
M
A
N
E