C. 2OOV2 W D 300 N/3 W.
A 128 V B.60 N/2V C.120V D 155 V 3.,
124
Cty TtWit nrv D VVH KhangVlft Huong dan
U„ = Ju,^|+U, i 2+2U„,U„2Cos(cp2-cp,) = W- + 3.60^ + 2.60.60^3 cos^ = 120(V) U=-Iil = 60V2(V) r^ChonB.
V2
V i d u 4: Cho doan mach xoay chieu AB gom hai doan mach A N va N B mac noi tiep. Dat vao hai dau doan mach AB mot dien ap xoay chieu on d j n h U A U = 200N/2 cos(1007tt + 7t/3) ( V ) , k h i do dien ap tuc thoi giCra hai dau doan mach NB la U N B = 50N/2 sin(1007it + 57x/6) ( V ) . Bieu thuc di^n ap tuc thoi giua hai dau doan mach A N la f^o-, t i ^-^^^ - > ' J Ạ U A N = 150 72 sin(1007it + 7i/3) ( V ) . B. U A N = 150 V2 cos(1207xt + 7i/3) ( V ) . C. U A N = 150N/2 cos(1007it + 71/3) ( V ) . D . U A N = 250N/2 cos(1007:t + 7t/3) ( V ) . Huang dan Uf^B =50^2 sin 1007Ct + 6 = 50V2 cos 1007tt + - 3 A B - U N15 = 15072 cos (V) 1007tt+- 3j ( V ) =^ChonC.
V i d u 5: Cho doan mach xoay chieu khong phan nhanh. A , B, C va D la 4 diem tren doan mach dọ Bieu thuc dien ap tuc thoi tren cac doan mach AB, BC va C D Ian l u o t la: ui = 400 V2 cos(1007tt + n/4) (V), U2 = 400cos(1007it - n/2)
(V), U 3 = 500cos(100nt + n) (V). Xac d i n h dien ap cue dai giOa hai diem A, D.
Ạ 100>/2V. B.IOOV. C . 2 0 0 V . D . 2 0 0 V 2 V .
nf.>; . u * i Hiiongdan V
Cdchl: .Ụ..,. . - v l . - ' • • :
u = u, + U 2 + U 3 =coscot(Ai coscp, + A 2 C o s ( p 2 + ...)-sincot(Ai sincp, + A j sintpj + - ) u = cosl007tt 40074. cos - + 400 cos — + 500 cos T:
4 2
-sinlOOnt 40074. sin - + 400 sin — + 500 sin n
4 2
= -100cosl007tt(V) = 100cos(1007ct + 7t)(V) => Chon B. ^ .{nlutii nif- ;
Cdch 2: u = 4 0 0 7 2 Z - + 4 0 0 Z - - + SOOZjt = -100 'ith iftrf o mdl 3^,;.<j{^.n'}-'
=^u = -100cosl007rt(V) = 100cos(100;tt + 7t)(V) . ' ' U ' , ^ • ^ ^ =>ChonB.
V i d u 6: Dat dỉn ap u = Uocos(1007it + 77i/12) (V) vao hai dau doan mach A M B
thi bieu thuc dien ap giiia hai dau cac doan mach A M va M B Ian luot la
U A M = 100cos(1007it + 7t/4) (V) va U M B = Uoicos(1007tt + 37t/4) (V). Gia trj Uo va
try KIS„ th^c V^t II LTBtl tren kcnh VTV2. t^p 2 - c„u l u n B u „
Ạ IOOV2 V v a l O O V .
C. TOO V va 100 V2 V. : D. 200 V v a l O O V s V, B. ^00^/3 V v a 2 0 0 V.
Huang datt
Phirong t r i n h u = UAM + UMB hay . ^ ,
Uo cosf lOOnt + ^ 112 = lOOcosf lOOnt + + Ui„ cos I lOOnt + ~ j d u n g voi t. ' D e tinh cac bien dp con lai thi ta c6 the chon cac t dac biet.
Chon t = (s) thi 400 U() cos n 7n
4 "^12; = 100 cos + Ujo cos
,.,f:l . 4 ^ 4
ạ/:Chon t = - - ( s ) t h i , ,v/}'(£\ •.•MK)rteo:> SVOSf ,
^7t 771) / U„=200(V) >200cos > Chon D. U 12 = 100 cos 7C 7t U ^ 4 , + U]() cos n 37t) U 4 • Ujo =100,73 ( V )
C / i i i 1/: N(?M síc di/n^v^ f^fl«/i f/zflo may tinli ton^ hap dao dong thi c6 the dim ,. phuang phdp thu tumig doi nhanh.
•"'> • . • .1.1 U : i :!U
d. Dm vao dau hieii vuong pha detinh cac dai hnmg .6
T
* H a i t h o i d i e m v u o n g pha t2 - t[ = (2k +1) — => + X2 = Â .2" -&ịo:>n
H a i d ^ i lug-ng x, y v u o n g p h a y
V ymax = 1.
Chang h?n UK v u o n g pha v o i IJL y a uc nen: <
IX- ,2 i ' ,2 i ' = 1 ff ^ 2 2 + + I U L V2J 2 + ( I U R7 2J 2 + .Uc^/2J = 1
. v - i i u i i i c i c n uien xoay chieu K, L, C mac nói tiep theo t h u t u d o (cupn cam thuan). K h i d o dien ap hieu d u n g 6 hai d a u dien t r o R la 200 V. Khi dien ap tiVc t h a i a hai dau doan mach la 100^2 V t h i dien ap tiic thoi giiJ''' hai dau dien t r o v a cuon cam deu la -100N/6 V. T i n h g i a trj h i | u d y n g cu3 dien ap 6 hai d a u doan mach AB.
Ạ 500 V. B. 615 V. C. 300 V . , D .2 0 0 V .
U R7 2J [ U L ^ J ^'^[-J^j \U[:jT) = ^ = ^ U L -2 0 0 7 3( V ) 26
Cty TISIIH MTV D VVH Khang Vl^t
u = U K + U L + U C =>100>/2 = - 1 0 0V6 - 1 0 0V6 + U C = > U C = 100(>/2 + 2^/6)(V) URN/2 u c ' U r V 2 = 1=> - I O O V 3 I \2 100(>y2+2x/6) U c V 2 ^2 = 1 => Uc = 200(1 + 2 V 3 ) ( V ) => U = 7 U R + ( U L - U c f = 615(V) =>ChonB. ' T ' - " i ' - ' ' • •.'•'^
V i d y 2: Doan mach xoay chieu theo d u n g t h u t u R, L, C mac nol tiep. D i e n ap tuc thai gii>a hai d a u doan mach lech pha la cp so v a i cuang d p d o n g dien tuc thai qua mach va bien d o dien ap tren R la UOR. O thoi d i e m t, dien ap tuc thai 6 hai d a u doan mach chua L C la ULC v a d i e n ap tuc thoi gi&a hai dau d i^ n t r o R la UK thi
Ạ UOR = ULccoscp + URsincp. B. UOR = uucsincp + URCOScp.
C. (ui,c)2 + (uK/tan(p)2 = (UOK)^. D . (UR)^ + (ui.c/tancp)^ = (UOR)2.
, . , „ Huong dan
UoLC
tancp =
U, OR UQLC = UoK tancp
\2 '„ , • . ' - '-U, OLC J = 1 U, OLC J = 1 N2, tancp 'orif oiiV' SI f\, = UgR . V =>ChonD. ' • • ' ^ ' ;^
Chu y: Vi UR vuong pha voi 111. va uc ncn a mot thai diem nao do UR = 0 thi
" U L = U( )L A1C = - U ( ) c ,
. " L = - U o L, U c = + U o c
V i d u 3: Doan mach xoay chieu A B noi tiep gom dien t r o thuan R, tu dien C va cuon cam thuan L. Goi uị, uc, UR Ian l u p t la dien ap tuc thai tren L, C va R. Tai t h a i diem ti Ccic gia t n tuc thai ui (ti) = -20 V2 V, uc(ti) = 10 N/2 V, UR(ti) = 0 V. T a i thoi d i e m t2 cac gia trj tuc thai ui.(t2) = -10 72 V, uc(t2) = 5-j2V,
UR(t2) = 15 72 V. T i n h bien dp dien ap dat vao hai dau mach AB? Ạ 50 V. : , ., B. 20 V. C. 30 72 V. D . 20 72 V.
Z::;^0mi4^: .,,..v •„,.. Huangdan . ' - v - M,.-*""-::
t = t i
t = t o =>
U K =O - . ^''r^r:'-^'-':- ; ; ^ | u o L = 2 o 7 2 ( v )