^hdn tick m hu&ng ddn gidi
Su dung may tinh:
Taco: u = UR + UL = ^ UL = u - UR = 100x/2Z J - lOOZO = lOOZ^ Vay: u =100cos Vay: u =100cos
Chgn dap an A
lOOTlt V
V i d u 6 : Dat dien ap u = Uocoscot vao hai dau tu dien c6 dien dung C thi cuang do dong dien qua tu dien la cuang do dong dien qua tu dien la
A. i = COC.UQ cos C. 1 = ; = ^ C O S V2 cot + — 2. 71 (Ot + — 2, B. 1 = — p ^ c o s D. i = coC.UoCOS 71 cot-- 2.
<Phdn tick ra hu&ng ddn gidi
Vi mach chi c6 ty nen: (Pi==(pu+r = 0 + X = T ^0=^ = COCUQ
2 2 2 Z-c
V?iy: i = W C U Q C O S
Chpn dap an A
cot + — 2
V i d g 7: Dat dien ap u = 120cos(100nt + - ) V vao hai dau mpt doan mach gom cuon cam thuan mac noi tiep di?n tro thuan R = 30Q thi di^n ap hi^u gom cuon cam thuan mac noi tiep di?n tro thuan R = 30Q thi di^n ap hi^u dung hai dau cupn cam la 60 V. Dong di^n tire thai qua doan m?ch la
A. i = 2N/2COS 1007tt + — (A). C. i = 2V2cos(1007rt--)(A). C. i = 2V2cos(1007rt--)(A). 4 B. i = 2N/3COS D. i = 272 COS 1007tt + -6y 1007:t + - , (A). (A).
(phdn tich ra huong ddn gidi
CUf TNHH MTV nwil Khaug Viet
^hdn tich vd hit&ng dan gidi
Thong thuang khi vic't bic'n thi'ic dien dp ci'ia hai dau doan mach ndo do ta phdi tinh duox dien dp cite dai gifta hai dau doan mach do vd do lech pha cua no so vai cwdii'^ do dong dien trong mach. Doi voi bni nay tht de Idm nhw vqy rat ddi so v&i tiiai gian cua mot bdi trdc nghiem.
Tuy nhien ta c6 the Idm vice do tuong doi dan gidn neu chii y den nhung giu kien bdi todn cho.
Theo gia thiet \Jc = U K ^ = R
Gia trj ciia L de Ui eye dai thoa man: Z[ = — - — — -> Z| = 2R
D Q l^ch pha g i u a UKi. va i : tancp,., =-?L = 2^ ( n n , = — \
R 1 8 0 '
Khi Ui cue dai , thi U I m.,. = -^-j^ ^ - UN/2 = IOOV2 ( V )
Ket hop v d i bieu thuc - Uf< + ( U L - U C ) ^ U K = ^ = 50V2V U R L = = ^ ( 5 0 7 2 ) ' + ( 1 0 0 / 2 ) ' = 50V1OV
Vi U I max nen U ^ c 1 U -> ip - (pK(^ = -
- Z
Mat khac tancp^;^ =^ — ^ = - i ^ =
R 4
71 (adsbygoogle = window.adsbygoogle || []).push({});
Vay do IC^ch pha giua UUL. va u mach Am = — - - = — (rad)
180 4 10
Bieu thuc dien ap gii>a hai dau cua dien tro va cuon day: V U K L =100^/5cos Chpn dap an A f n ^ 1007rt + — V 1 0 ;
Vl du H : Dat mot dien ap xoay chieu u = 200 cos(100TTt + ^) vao hai dau
doan mach m^ic nol tiep theo t h u t u cac phan t u gom m o t dien t r o thuan R, m o t tu di$n eo dien d u n g C va mot cupn cam co do t u cam L thay d o i , duoc. Dieu chinh L de dien ap gii>a hai dau cuon day dat cue dai t h i k h i do di$n ap giCra hai dau cua tu dien la Uc = 100 V . Hay viet bieu thiic giOa hai dau ciia R va C
Bi quyct on luyftt thi dai hqc dat diem toi da Viit I"!' ' - Van Vinh
" R R 60 ' 4
Vay bieu thuc c u o n g d p dong dien trong mach: i = 2N/2 cos
Chpn dap an C
1007lt + -
. 4
Vi du 9 : Dat dien ap u = U„eos lOOTTt--
3 j
j(V) vao hai dau m p t t u d i ^ n c6 d i ^ n d u n g ^'^^ (F). 6 thoi diem di^n ap giua hai dau tu dien la 150V
n
thi cuong dp dong dien trong mach la 4A. Bieu thuc cua c u a n g d p dong dien trong mach la
,-4 A. i=472cosfl00T:t + - A. i=472cosfl00T:t + - 6 ( A ) i C. i = 5cos lOOrct — 6 :(A) B. i = 5cos D. i = 4V2cos 1007lt + - , (A) ' l 0 0 7 t t- - l( A ) D u n g khang: ZQ =
<Pkan tich vd huang ddn gidi
1 1 ,-4 = 50Q
Mach chi c6 t u nen i sam pha h o n u m p t goc - :
i ^ u2 i ^ + = 1 <=> " , + ^ = 1 => In = Z6-I,1 I 0 1 so- so^ + 42 = 5 { A ) 71 71 71 7t 9 . - c p u - 2 = ' l " 2 = 6
Vay bieu thuc c u a n g d p dong dien: i = 5 c o s Chpn dap an B
^ 71^ 1007lt + - 1007lt + -
6 ,(A)
V l du 1 0 : Dat vao hai dau doan mach m p t d i f n ap xoay chieu
u - 100N/2cos(a)t) (V) g o m mpt di?n tro thuan R, cuon day thuan cam c6 d p t u cam L thay d o i dupe va mpt tu d i ^ n c6 dien d u n g C. K h i thay doi
L ta thay Ui dat cue dai va h i ^ u d i ^ n the hai dau t u d i ? n b^ng hi?u di?n t h e h a i dau d i ? n t r o thuan. Viet bieu thuc di?n ap giija hai d a u cua U ^ L t h e h a i dau d i ? n t r o thuan. Viet bieu thuc di?n ap giija hai d a u cua U ^ L
A. URL =100N/5COS C. U R , =200V5COS C. U R , =200V5COS 1007tt + — 10 100nt + — , 10; V B. URL = 200N/5COS V D. URL = lOoVscos lOOTtt- — V 10, f 71 lOOTtt 10 V
Pha ban dau ciia hi#u di#n the: (p = (Pu-9i=>'Pu =<Pi+<p=-— + — = 0
4 4 Bieu thuc hieu dien the: u = UQ cos(cot+ (pu) = IOOV2 cos(1007it)V Bieu thuc hieu dien the: u = UQ cos(cot+ (pu) = IOOV2 cos(1007it)V (adsbygoogle = window.adsbygoogle || []).push({});
Chpn dap an D
Cau 2: Cho mach di?n gom RLC noi tiep.
Di^n ap hai dau mgchu = 220^2 cos(1007tt + ^ ) ( V ) . Di?n tro R = 50>/3 L la cuon day thuan cam c6 L = — H , di^n dung C = ——F, bieu thuc cuong la cuon day thuan cam c6 L = — H , di^n dung C = ——F, bieu thuc cuong dp dong di^n trong mach:
A. i = 2,2N/2cos 1007tt + — A 1 2 , 1 2 , C. i = 2,2>/2cosfl007rt-- l 6) B. i = 2 cos D. i = 2cosl007tt A lOOnt-- I A 6,
'Phdn tick vd hu&ng ddn gidi
Cam khang: = L.to = -^1007: = 50Q
7t
Dung khang: ZQ = 1 1
(o.C IOOTT. 10 1-4 = lOOQ
T6'ng tro: Z = ^R^HZ^-Z^f = x/(50V3)2+(50-100)2 = lOOQ
Cuong dp dong dif n cue dai: lo = = ^ ^ " ^ = 2 2^/2 A Z 100 ' Z 100 ' Dp l#ch pha: tan 9 = ^LZ^ = ^0-100
R 5073
Pha ban dau cua cuong dp dong dien:
N/3 7t ,
- - = ^ c p . - - r a d cp = (p„-(Pi=^cp.=cp^_(p = i E _ Z L = ^ cp = (p„-(Pi=^cp.=cp^_(p = i E _ Z L = ^
4 6 12
Bieu thuc cuong dp dong difn: i = IoCos(cot + (Pi) = 2,2N/2cos 1007tt + ;^ (A).
V 12/ Chpn dap an A