A ^ ^ M B X u ,R O M Up u ,CO: = 60* A Huong •E dan O K h i mac n o i tiep cuon day v o i doan mach X: U^^ = IZ^^ = 3.50 = 150 ( V ) , -n Ti Ve gian d o vec t o : s^x = ^•(ttU'jII'f'rHiO i\\ U =j 250^ = 150^ + B It = Ucd L U x U = U u U x = 0 ( V ) =4>Px = U x I c o s x = 0 ( W ) C h o n B V i du 12: H a i c u o n d a y c6 d i e n t r o t h u a n v a d o t u c a m I a n l u g t la R i , L i v a R2, V i du 10: M o t cuon day c6 d i e n t r o thuan R = 100 N/S Q va d o t u cam L = 3/^ L2 d u o c m a c n o i t i e p n h a u v a m a c v a o m o t d i e n a p x o a y c h i e u c6 g i a t r j (H) Mac n o i tiep v o i cuon day m o t doan mach X c6 t o n g t r o Zx r o i mac vao h i e u d u n g U G o i U i v a U2 la d i e n a p h i e u d u n g t u o n g tVng gii>a h a i d a u hieu dien t h e x o a y chieu c6 hieu dien t h e h i e u d u n g la 120 V, tan so 50 Hz c u o n ( R i , L i ) v a (R2, L2) D i e u k i e n d e U = U i + U2 la t h i thay d o n g d i e n qua mach nhanh pha 30" so v o i hieu dien the hai dau A Li/Ri = L2/R2 B Li/R2 = L2/Ri doan mach X va c6 gia trj h i e u d u n g 0,3 A Cong suat tieu t h y tren doan mach X la bao nhieu? A 30W • , •At „j C.9V3W B.27W Huang dan Z,rf = • - W • R dan U = U , + U j => (Pi = (P2 => tancpi = tancp R, Li L, Ri R, • Chon A v o i n h a u Doan mach A M g o m dien tro R i mac noi tiep v o i tu dien c6 dien =^U,^ =IZcd = ( V ) = D L1.L2 = 2R1.R2 V i dv 13: M o t doan mach A B g o m hai doan mach nho A M va M B mac n o i tiep + Zl = 200^/3 (n) tanked = - r Huong :r D 18x/3 C L1.L2 = R1.R2 d u n g C i Doan mach M B g o m dien t r o R2 mac noi tiep v o i t u dien c6 dien X M d u n g C2 K h i dat vao hai dau A , B m o t dien ap xoay chieu c6 gia t r i hieu M ^ d u n g U t h i dien ap hieu d u n g gii>a hai dau doan mach A M la U i , dien ap hieu d u n g g i u a hai dau doan mach M B la U2 N e u U = U i + U2 t h i he thuc Ve gian d o vec to cho doan A M truoc, roi ve 60V3/ A" tiep doan M B tre pha h o n d o n g dien la 30" Ta nhan thay A A M B v u o n g tai M nen: lien he nao sau day la dung? A.CiRi=C2R2 120 V B C i R = C2Ri D CiC2RiR2= C.CiC2=RiR2 Huong dan Ux = M B = ^120^ - (60>y3)' = ( V ) Px = U x l c o s i p , = 60.0,3.cos30" = 9^/3(W) =^ Chon C U = U | + UT =>(P| = Binh luan: Sau fun dime MB sc tun dime ;^6c a roi gdc (p va P = UJcoscp V i du 11: C u o n day c6 dien t r o thuan R va t u cam L mac vao dien ap xoay chieu u = A* 250N/2 coslOOTct (V) thi d o n g dien qua cuon day CO gia t r i hieu d u n g la A va lech pha so v o i d u n g qua mach la A va dien ap giira hai dau cuon day v u o n g pha v o l dien ap gii>a hai dau X Cong suat tieu t h u tren doan mach X la A 200W C 2OOV2 W 120 B 0 W D 300N/3 W / ^ ':30^^'"" - Khi lien quan den gid tri tue thai cm u va i thi truac tien phdi vie't hieu thuc ciia 30' cuon day v o i doan mach X t h i c u o n g hieu a Tinh gin tri tux thai dim vao bicu thi'rc M dien ap hai dau doan mach la 7t/6 Mac noi tiep R , C , = R 2^2 ,C Chon A G i a tri tu'c thoi M coC, => tancpi = tanq)2 cac dai luang da truac >B ^ V i du 1: Bieu thuc cua dien ap giua hai dau doan mach la u = U()cos(1007it + n/4) (V) Biet d i e n ap som pha n/3 d o i v o i c u o n g d o n g dien mach va c6 gia t r i hi^u d u n g la A C u o n g d o n g d i ^ n t r o n g mach k h i t = 1/300 (s) la A V2 ( A ) B ( A ) C V3 ( A ) , D (A) 121 Huang i = 2V2,cos 1007tt + - u = U()Cos dan Giti tri ti'tc thai lien qiian dm xu hitang tang giiim ^ po'i v a i bai loan d a n g thong t h u o n g lam nhu- sau: lOOTlt 12 * QOOTI i = IQCOS cos (1/300) 300 71 ^ * = 2(A)=^ChonD 12 0,4/7i ( H ) , va m o t t u dien co dien d u n g l/(87t) (mF) D o n g dien t r o n g mach co bieu thuc: i = I(icos(1007rt - 2n/3) ( A ) Tai t h o i d i e m ban dau dien ap g i i i a hai d a u doan mach co gia t r i -40 V2 i;,;Tinhl0 ; , j A V6 ( A ) • ' B Jh5 (A) •3 C Huang V2 > i j, (A) (V) >;'^-?'l D Vs (A) loCOS 80 'KI 71 =7i^(A)=>ChonB ' hai dau doan mach no'i tie'p g o m tu dien co dien d u n g C = 0,2/n (mF) va dien t r o thuan R = 50 Q H o i sau t h o i d i e m ban dau (t = 0) m o t khoang t h o i gian ngan nhat bang bao nhieu t h : dien tich tren tu dien bang 0? B 750 ((.is) C 2,5 (ms) Huong dan i , , j • = 50Q wC (V), >'', •• wt = — Thay gia t r i vao U K I , ta duoc: 4 •'Rl = 50 N/2 cos cot + — = 50V2 cos r =0 ,4 , i» 'i Chon A 4J V i d y 2: D a t vao hai dau doan mach g o m cuon day co dien t r o thuan R va cam hieu d u n g giua hai dau day va giCra hai ban tu dien Ian l u o t la Ud = 50 (V) va Uc = 70 ( V ) K h i dien ap tufc t h o i giua hai ban t u d i e n co gia t r i uc = 35 >/2 A, -25 V6 ( V ) = -1 B -50 V2 (V) (D = 7t/4 ma uc tre h o n i la n/l nen uc tre pha h a n u la 7r/4 D o do: lOOjtt COS lOOTit - " - = 2 t = 12,5.10"^^ (s) => Chon D ^ ' C 50 (V) D 50 ^/2 ( V ) Huang dan tan(p,^L=-Tr R = ,, ^ = ' ^ K L = ? 571 2J lOOTit - ^ - ^ = - | + i r ^ t = 22,5.10"'^ (s) 122 -' >/2 (V) va d a n g g i a m thi dien ap tuc thai giiJa hai dau cupn day co gia t r i la R D o u tre pha h o n i la Uc = 0: =1 R D 50 khang Z L = R^/3 mac no'i tiep v o i tu dien C m o t dien ap xoay chieu, dien ap D 12,5 (ms) = UQ(2 C 50 (V) Theo bai uc = 70 V va dang tang nen nam nua d u o i V T L G V i d u 3: D a t dien ap xoay chieu u = U()cos(1007ct — n/2) (V) (t bang giay) vao UQ V2 ( V ) Ne'u bieu thuc d o n g dien la i = I(, coscot v3 -Zc B -50 Huong dan cos(1007it-;t) U(o) = Io-y=cos(1007C.O-7r) = - o V ( V ) = > I „ tancp = va Uc = 70 (V) K h i dien ap tiVc thoi giira hai ban tu d i ^ n co gia t r i uc = 70 (V) 80 (p = 80 Zc = khang Zi = R mac noi tiep vcVi tu dien C m o t d i ^ n ap xoay chieu, d i ^ n ap U e =70V2cos c o t - - l ( V ) 0 n t - y ^ + (p = 1,- A 25 ().is) d o a n mach g o m cuon day co d i e n t r o thuan R va cam hieu d u n g giua hai dau day va gifra hai ban tu dien Ian l u p t la Ud = 50 (V) lOOnt-3 U = IgZCOS JJV ; ; i Thay gia trj cua cot vao bieu thuc can t i n h A R = * V i d y 1= tan tpiu = tan i« va dang tang t h i dien ap tiVc t h o i g i i i a hai dau cuon day co gia t r i la , = 80(Q) wC ' Di.ra vao V T L G va xu h u o n g tang g i a m de xac d j n h (cot + cp) (tang t h i n a m dan 3" Z, =(oL = ( ) , Z e = ' nua d u a l V T L G , giam t h i n i i a tren); V i d u 2: C l i o m o t mach dien k h o n g phan nhanh g o m dien t r o thuan 40/^/3 Q, cuon day t l i u a n cam co t u cam Viet b i e u thuc cac d a i l i r o n g co lien quan; UQ =:70>/2COS c o t - ^ ' = ly COSCOt ui^L - ->COt 2, 50\/2 COS ©t + — = 50 72 cos (5n = +— : cot = — + — = -25N/6(V) 3) ;;=:> Chon A 123 c Cty TtWit nrv Cgni^ cac ^in tri ti't'c thai (ton^ Iiap aic dao dong dicu hoa) Ta can phan biet gia trj cue dal (Uo, lo l u o n d u a n g ) , gia tri hi^u d u n g ( U , I = U„ = J u , ^ | + U , i + U „ , U „ C o s ( c p - c p , ) = W- + ( U L - U c ) ' ; u = u,, + u^ + uc 2c V i d u : M a c h dien xoay chieu k h o n g phan nhanh g o m dien t r a thuan R, cu6n U=-Iil = 60V2(V) V2 + 3.60^ + 2.60.60^3 cos^ = 120(V) r^ChonB cam t h u a n co cam k h a n g Zi, va tu dien c6 d u n g khang Zc = Z i Vao mot V i d u 4: Cho doan mach xoay chieu AB g o m hai doan mach A N va N B mac noi thoi d i e m k h i hi^u dien the t i e n dien t r o va tren tu di?n c6 gia t r i tuc thoi tiep Dat vao hai d a u doan mach A B m o t dien ap xoay chieu o n d j n h U A U = t u o n g u n g la 40 V va 30 V t h i h i ^ u dien thegiCra hai d a u mach dien la 200N/2 cos(1007tt + 7t/3) ( V ) , k h i d o dien ap tuc t h o i giCra hai d a u doan mach A 55 V N B la U N B = 50N/2 sin(1007it + 57x/6) ( V ) Bieu thuc d i ^ n ap tuc t h o i giua hai B 60 V - ^•'-'.•^ C 50 V ^'"'• D 25 V dau d o a n mach A N la Thay u,^ = ( V ) , = 30(V) va u, = - u ^ — = - ( V ) vao he thiVc: u = U R + U | + U c => u = 40 + (-10) + 30 = 60(V) => Chon B f^o-, cam t h u a n co cam khang Zi va tu dien c6 d u n g k h a n g Zc = Z L Vao mot A 20 V B 60 V C 50 V B U A N = 150 V2 cos(1207xt + 7i/3) ( V ) D U A N = 250N/2 cos(1007:t + 7t/3) ( V ) Huang dan Uf^B =50^2 sin 1007Ct + AB - D lOOV > Hucmgdan U L uc =30 i ivu =-3UL o =-90 A 100>/2V heat la: UAB = Uoicosicot + cpi) (V), unc = Uo2cos(cot + (pi) (V) thi bic'u tlii'ec dicn lip trcn doan AC la UAC - UAU + UBC tan(p = UQI'^'"^! doan mach Bieu thuc dien ap tuc thoi tren cac doan mach A B , B C Ian UBC = c o s ( ] O O K t + 27t/3) ( V ) Dien ap hieu d u n g giira hai d i e m A , C la B 60N/2V D.200V2V Hiiongdan - v =coscot(Ai coscp, l - ' +A2Cos(p2 V • • : + ) - s i n c o t ( A i sincp, + A j sintpj + - ) u = cosl007tt 40074 cos - + 400 cos — + 500 cos T: = -100cosl007tt(V) = 100cos(1007ct + t ) ( V ) => Chon B COS92 = 60cos(100Kt + n/6) ( V ) , C.200V -sinlOOnt 40074 sin - + 400 sin — + 500 sin n V i d u 3: Cho doan mach xoay chieu k h o n g phan nhanh A , B , C la ba d i e m tren A 128 V U , U2 + U + U ( ) ^'"'P2 •(13 rrf UAii Cdchl: u = u, + •2U„,Uo2COs((p2-(p,)''^*'^'"' U()| cos(pi + U()2 l u o t la: B.IOOV nf.>; u * i khong phan nhanh va bic'u thi'ec dicn ap tuc thai trcn cdc doan mach AB, BC livi Cdch 1: n/2) (V), U = 500cos(100nt + n) (V) Xac d i n h dien ap cue d a i giOa h a i d i e m A, D Chti y: NcU A, B, C tlwo di'ini^ ihi't tir la ba diciu trcn doan mach dicn xoay ch ICII 02 3j V i d u 5: Cho doan mach xoay chieu k h o n g phan nhanh A , B, C va D la d i e m I-; I 1007tt+- ( V ) =^ChonC va C D Ian l u o t la: u i = 400 V2 cos(1007tt + n/4) (V), U2 = 400cos(1007it U K = - ( - ) - = 100(V) => Chon D • • fit = 15072cos U N15 tren doan mach Bieu thuc dien ap tuc t h o i tren cac d o a n mach A B , BC u = 40 U - Ui - Ur = 50V2 cos 1007tt + - ( V ) ,, + to- -> 'J C U A N = 150N/2 cos(1007it + 71/3) ( V ) t h o i d i e m dien ap hai dau doan mach va tren cuon cam co gia t r j tuc thoi t u o n g i r n g la 40 V va 30 V t h i dien ap tren R la t i ^-^^^ A U A N = 150 72 sin(1007it + 7i/3) ( V ) V i d u 2: M a c h dien xoay chieu k h o n g phan nhanh g o m d i ^ n t r o thuan R, cuon 124 KhangVlft Huong dan l u o n d u o n g ) va gia trj tuc thoi (u, i c6 the am, d u o n g , bSng 0): U5 = u,^K + ( U , „ - U o c f ; D VVH Cdch 2: u = 0 Z - + 0 Z - - + SOOZjt = -100 ^ {nlutii 'ith iftrf o mdl =^u = -100cosl007rt(V) = 100cos(100;tt + t ) ( V ) ' nif- ; 3^,;.ChonB V i d u 6: Dat d i ? n ap u = Uocos(1007it + 77i/12) (V) vao hai d a u d o a n mach A M B t h i bieu thuc d i e n ap g i i i a hai dau cac doan mach A M va M B Ian l u o t la C 120 V D 155 V 3., U A M = 100cos(1007it + 7t/4) (V) va U M B = Uoicos(1007tt + 37t/4) ( V ) Gia t r j Uo va Uoi Ian l u g t la 125 try KIS„ th^c V^t II LTBtl tren kcnh VTV2 t^p - c„u l u n B u „ A IOOV2 V v a l O O V B ^00^/3 V v a 0 V C TOO V va 100 V2 V : u =UK D 200 V v a l O O V s V, Huang j d u n g v o i t D e t i n h cac bien d p lai t h i ta c6 the chon cac t dac biet U() cos 771) U 12 > Chon D + Ujo cos U„=200(V) ^ / 7C 7t U ^4, + U]() cos n U 37t) , • Ujo =100,73 ( V ) 1/: N(?M si'c 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 T H a i t h o i d i e m v u o n g pha t2 - t [ = (2k +1) — => y H a i d ^ i lug-ng x, y v u o n g p h a V ymax IX- -&i.o:>n d a u d i ^ n t r o R la UK thi B UOR = uucsincp + URCOScp C (ui,c)2 + (uK/tan(p)2 = (UOK)^ D (UR)^ + (ui.c/tancp)^ = (UOR)2 tancp = UoLC U,OR ^ + IULV2J i' =1 =>ChonD '„ , • ' - N2, '- tancp =1 ' 'orif oiiV' SI f\, = UgR V • • ' ^ ' ;^ , V i d u 3: D o a n mach xoay chieu A B noi tiep gom dien t r o t h u a n R, t u d i e n C va cuon cam t h u a n L Goi ui., uc, UR Ian l u p t la d i e n ap tuc t h a i tren L, C va R Tai t h a i d i e m t i Ccic gia t n tuc t h a i u i (ti) = - V2 V, uc(ti) = 10 N/2 V, UR(ti) = + Uc^/2J =1 hai d a u dien t r o v a cuon cam deu la -100N/6 V T i n h g i a t r j h i | u d y n g cu3 V T a i t h o i d i e m t2 cac gia trj tuc thai ui.(t2) = -10 72 UR(t2) = 15 72 A 50 V : t = ti V, uc(t2) = 5-j2V, V T i n h bien dp dien ap dat vao hai d a u mach AB? , , C 30 72 V B 20 V Z::;^0mi4^: ,, v •„, UK=O - Huangdan ' - v - ^''r^r:'-^'-':- D 20 72 V M,.-*""-:: ;;^|uoL=2o72(v) U L = -UoL = -2072(V);uc = Uoc = ( V ) [ U o c -1072(V) d i e n ap h a i d a u d o a n mach A B C 300 V , \U[:jT) D.200 V = ^=^UL-20073(V) t = t o => U,OR / + U[ \2 = !=> ri572^ I UOR, + r-io72] = l = > U o R =1076(V) [2072 J Uo = V U o R + ( U o L - U o ) ' = ( y ) =>chonD 26 UQLC = UoK tancp \2 dien ap tiVc t h a i a hai dau doan mach la 100^2 V t h i dien ap tiic t h o i giiJ''' ^'^[-J^j dan "L =-UoL,Uc =+Uoc ,2 u i e n xoay chieu K, L, C mac no'i tiep theo t h u t u d o (cupn [ U L ^ J Huong " U L = U ( ) L A C =-U()c cam thuan) K h i d o d i e n ap hieu d u n g hai d a u d i e n t r o R la 200 V Khi UR72J , „ Chu y: Vi UR vuong pha voi 111 va uc ncn a mot thai diem nao UR = thi = (IUR72J B 615 V •.'•'^ A UOR = ULccoscp + URsincp U,OLC J 2" + X2 = A^ C h a n g h?n UK v u o n g pha v o i IJL y a uc nen: < A 500 V =1 tuc t h a i hai d a u doan mach chua L C la ULC v a d i e n ap tuc t h o i gi&a hai ff v-iiu iiicicn UcV2 ^2 tuc t h a i q u a mach va bien d o dien ap tren R l a UOR O t h o i d i e m t, d i e n ap : i :!U d Dm vao dau hieii vuong pha detinh cac dai hnmg \2 "i'-' ' • 'T'- , C/iii * 100(>y2+2x/6) -IOOV3I => Uc = 200(1 + V ) ( V ) => U = U R + ( U L - U c f = 615(V) =>ChonB , ,v/}'(£\ •.•MK)rteo:> SVOSf = 100 cos = 100(>/2 + 2^/6)(V) tuc t h a i gii>a hai d a u doan mach lech pha la cp so v a i c u a n g d p d o n g d i e n a./:Chon t = - - ( s ) t h i ^7t = 1=> =>UC Vl^t V i d y 2: D o a n mach x o a y c h i e u theo d u n g t h u t u R, L, C mac n o l tiep D i e n ap (s) t h i 400 n 7n = 100 cos "^12; ,.,f:l >200cos =>100>/2 = - 0 V - 0 V + U C uc' UrV2 URN/2 ^, + Ui„ cos I lOOnt + ~ Uo cosf lOOnt + ^12 = lOOcosf lOOnt + Chon t = + U L +UC datt P h i r o n g t r i n h u = UAM + UMB hay ' Cty TISIIH MTV D VVH Khang { • ••^'"''^ 127 Ba trp hicn thiic V^t li L TON tren kenli VTV2 tap - Cliu V^n Bl&n V i d u 4: D a t d i e n a p V2 V - 50 H z v a o h a i d a u d o a n m a c h A B g o m h a i d o a n A M v a M B m a c no'i tie'p D i e n a p t r e n d o a n A M v a d o a n M B l e c h p h a n h a u 71/2 V a o t h o i d i e m to, d i e n a p t r e n A M b a n g 64 V t h i d i e n a p t r e n M B l a V D i e n a p h i e u d u n g t r e n d o a n A M C O t h e la A 40>/^V ^ B.50V Huang " A M n I " A M U " M B " M B U Q A M * f^^jUoAM J OAM = d u =80(V)=^UAM UOAM; =4072(V) V 50/^/3 Q V a o t h o i d i e m to, d i e n a p t r e n A N b a n g 80\/3 B 150 V Y = ^ -z j =^ ^ A N ZAN = ^ " 7J ^ ••MB J V'QZMB = => } B.50V3V Z, -7c r R C.40V2V Huang - Z c f + (ZL f 36 ^ ^ 64 ^ V '-'(1MB J i = IQ COS " A N -Zr -1 R >/3 " ^ " A N - L U M B +^1= = 60(V)=>U^M UoMB =SO(V) -I 0 = — I n = 80>/3 rV = l=^Io =^y3(A) 100 = V ^ ^ ^ = 50V7 = -^;Z,3 =; L cos cotCOS 7t = = > IQ s i n IT Wt + — 3; cot + — =30^/2(V) •Chon D ditMi ^ a p g i u a h a i d a u d o a n m a c h M B c the la A U A M = 50cos(cot - 571/12) ( V ) ^ B U A M = 50cos(a)t - 7i/4) ( V ) C U A M = 200cos((ot - 7i/4) ( V ) D U A M = 200cos(a)t - 57t/12) ( V ) = ^ ( Q ) Hii&ngddn = - ' ' = ^ " A M ^ " M B = 30 + ^OAM V L'uMB ) lo = -73 U 0MB + = 50(V) = V '-'oMB '-'oAM J U,l\ 40N/3 " M B " A M r»(5< • Z,, - Z c ChonC (V) d u n g d ? t u c a m L Bie't L = r R C V a o t h o i d i e m to, d i e n a p g i i r a h a i d a u c u o n c a m b a n g 40N/3 V t h i —(") 60 37 100, " M B n UoMB hai d o a n A M v a M B m a c n o i tie'p D o a n A M g c i m t u d i e n c d i e n V '-'oAM J (Dt + — = UoAM+UdMB=100- cot = IOOIQ C O S 'Ml! u OAM •^PMB V '-'oAM • • A M -L " M B = I = rRC: Cdch 2: ( ^AM = - ^ =^ Uo = IflZ = I O V / R ^ dan D V V n o i tie'p v o i d i e n t r o R v a d o a n M B c h i c6 c u o n c^m c d i e n t r a t h u a n r v a c6 100 ( lOOIoJ " u OAM thi dien ap tren 100(") = '''MB = - J ' - Z M S = \ " A N ' '" khang _,^anorif>c:c I f V 'OZAN + 7u -1 L = rRC D lOOTsV •'' = n o i tie'p vcVi ctien t r o R v a d o a n M B c h i CCT cuc)n c a m c d i e n trtV t h u a n r v a c6 V i d u 7: D a t d i e n a p u = 100cos((i)t + 7T/12) ( V ) v a o h a i d a u d o a n m a c h A B g o m ••• tancpMB = HQ f t :.>t AM, Hu&ngdan Cdchl: ^ , d i ^ n a p t r e n A M l a 36 V D i e n a p h i e u d u n g t r e n d o a n A M cc) t h e la 50\/3 Q, dung , ,, d t u ' c a m L Bie't L = r R C V a o t h o i d i e m to, d i e n a p t r e n M B b a n g 64 V t h i doan C 50 > y V • ' , :,l:^ ^u.t-.: khang voi dien _ hai docin A M v a M B m a c n o i tie'p D o a n A M g o m t u d i e n c6 d i e n d u n g C /v m a c h A B g o m ba doan , — = - => tancp^i tancpf^^; = - => u^, u,^^R — • Chon A d o a n M N chi d i e n t r a R = 50 Q v a d o a n N B c h i c6 t u tancp^N = -: =1 V^OMB M N v a N B m a c n o i tie'p D o a n A M c h i c6 c u o n c a m v o i c a m A lOOV • = 30^/7 ( V ) the tra hinh ditvi bie'u tlii'ir L = rRC /:/•(,'« A 50 V 5: D a t d i e n a p u = Uocoscot v a o h a i d a u M B l a 60 V T i n h Uo 36 UQ 1U„MB=60(V) Vi 64 = y i d u 6: D a t d i e n a p u = 100cos(o)t + 7:/12) ( V ) v a o h a i d a u d o a n m c i c h A B g S m J Hi UoMB - + D 50>/2V dan u M B C/jM t/-" D/C'H =>rR = - = Z | Z c ^ C V V ^ j, U„ = l„Z = 1„ > ^ + ( Z , - Z , f 30N/3(V) I J U0MB A, I "mV B 50* , [ i f g i a n d o v e c t o ta tha'y, U A M t r e p h a h o n lAi! UL la 7t/3 n e n M 129 Bo trp hie'n thiic U AM V^t li LTDH Cty mnn tren k&nh VTV2 t^p - Chu VHn BI6n (V) = COS cot + Huong Chon B 12 V i d u 8: M o t doan mach A B g o m doan A M va M B mac noi tie'p D o a n A M g6n^ d i e n t r o R n o i tie'p v o i t u dien C, doan M B chi c6 cuon c a m L D a t vao D VVH lUiang Vift dan MB • AAMB vuong tai M nrv tana = r n = Vs => a = 60" AM V i R = r nen p = a = > cp = a + p - " = 30" => coscp = 0,866 => Chon C A B m o t dien ap xoay chieu chi c6 tan so thay d o i d u g c t h i dien ap tuc thoj V i d u 10: M o t doan mach A B g o m doan A M va M B mac n o i tie'p D o a n A M tren A M va tren M B l u o n l u o n lech pha 7t/2 K h i mach coug h u o n g thi g o m t u dien C no'i tie'p v o i dien t r o R, doan M B chi c6 cuon cam c6 d p • d i ^ n ap tren A M c6 gia t r j hieu d u n g U i va tre pha so v o i d i ^ n ap tren AB tir cam L va dien t r o thuan r = R Dat vao A B m o t dien ap xoay chieu chi c6 m o t goc a i D i e u c h i n h tan so de dien ap hieu d u n g tren A M la U2 t h i dien tan so goc co thay d o i d u g c t h i dien ap tuc t h o i tren A M va tren M B l u o n ap tvVc t h o i tren A M lai tre h o n dien ap tren A B m o t goc Bie't a i + aa = 7t/2 luon lech pha nil K h i co = coi t h i dien ap tren A M co gia t r j hieu d u n g va U i = 0,75U2 T i n h he so cong sua't ciia mach A M k h i xay cong h u o n g U i va tre pha so v o i dien ap tren A B m o t goc a i K h i co = C02 t h i dien ap hieu A 0,6 B 0,8 C.l D 0,75 Huong cosai = HI \ u % =• = cosa, u sinai / + I uJ r u ^'7a^- ,U \ / \ = r^ = L/C sity u ^ ^ •=>tanP-^M cosp = • ' MB J MB AM C 0,75 va 0,45 Huong = 0,6 • (|) = a - / = tan a => a = P => cp = 2a - 90 AM = t a n a => P = a => coscp = sin 2a u TH2:cosa2 = MB MB THl:cosa, = H I "MB • D 0,96 va 0,96 dan •^tanP = A M = cosp = • MB J M AM B 0,45 va 0,75 sinp = AM / sinp = - m o t goc Bie't a i + a2 = 7i/2 va U i = U2 Vs T i n h he so cong sua't ciia mach u n g v o i COI va C02 0,75 = 11 / Chu y: Tu dieu kien d u n g tren A M la U2 va dien ap tuc thoi tren A M lai tre h o n d i e n ap tren A B A 0,87 va 0,87 u \ B dan ^ u) R A = sin a I U) + r_ ^/3 I u) • cos(p = sin 2a MB V i d u 9: D o a n mach xoay chieu A B g o m M h a i doan mach A M noi tie'p M B D o a n m a c h A M g o m dien t r o R n o i tie'p v a i t u dien c6 dien d u n g C, doan mach M B CO cuon cam c6 d o t u cam L va dien t r a r Bie't R^ = r^ = L/C va dien ap hieu / d u n g giij-a h a i d a u M B I o n gap V3 d i e n ap h a i d a u A M A 0,887 V-l- / so' cong sua't •"• ciia A B la , / 0, / B 0,755 • C 0,866 D 0,975 Khi L thay doi deUum, thi 0,^^ (URC va U la hai cqnh cm tain giac vuong dm Uumx la cqnh huyen, UR la dumig cao thuoc cqnh huyen): &itfp kidit thvtc vai i(ii-hti tten k&nh VTV2 t^p2-chu K/n' C thay dot dcUcmx tin 0,^, f r U UV2 f = 1; 1 K h i t o n g so k h o n g d o i , tich so Ion nha't k h i so bang nhay ^ R+ > 2|Z| - Zcl (R + r) + V i d u 11: Cho mach dien xoay chieu R, L, C m3c rioi fi#p theb t'HiVfe rfo (cuon cam thuan) D i e n d u n g C c6 the thay d o i duoc D i e u c h i n h C de dien ap , \|, K h i tich s o k h o n g d o i , tong nho nha't k h i so bang (UKI va U la hai cqnh cua tamgidc viian^ Uomn la cqnh Inn/en, UK lii dicaiii^ cao thuoc cqnh hiii/cn): UKL (a + b),„i„ = i : b a + b *^^u " = " xay k h i a = b a + b > VaTb = 1; UV2 UKCV2 van bleu * da'u " = " xay k h i R = |Z, - Z^ > 2|ZL - Zcl dau " = " xav.ra k h i R + r = IZL - Z ^ Tarn thitc hqc 2: y = f(x) = qx^ + bx + c (a ^0) hai dau C la ion nha't K h i dien ap hieu d u n g hai dau dien tro R la 100 V2 V K h i dien ap tuc thoi hai dau d o a n mach la 100N/2 V t h i dien ap \ tu'c t h a i g i u a hai dau doan mach chi'ia dien t r o va cuon cam la -100-76 V C 200 V B 615 V / \ T f h h gia t r j hieu d u n g cua dien ap hai dau doan mach A B A 50 v.- y D 0 V ^ :, ^• a >0 ymin 'KL uC =1 UV2 max •'fit?:.'';; '.i'iiv : X Hucmgddn (-^oo^/6 Urn f looVz \ V2 -b -A _ a > t h i tgi^di^h^P^r^^ql xo = — x6^^mm — •) rvw> • 4a 1 u RL Kl 100^2 4ac - g?il,r: Dao ham khao sat ham so BAi TOAN LIEN QUAN DEN C^C TR| Ham y f(a) De t i m gia trj Ion nhat va nho nhat cua m o t dai l u g n g (Z, I , UK, U I , Uc, U M N , L a p bang bien thien t i m eye t r j P ) k h i CO m o t yeu to bien thien thong t h i r o n g lam theo cac buck sau: Neu h a m so d o n g bien hoac.nghieh bien tren m o t doan [a, b] t h i max va mir Zi., Z t , w) the d u n g gian vec to phoi hop v d i d j n h l i ham so sin M o t bai toan c6 the giai theo nhieu each n h u n g t h u o n g chi c6 mot each hay va ngcin gon V i vay, nen tranh tinh trang "Diiiii^ dao mo trail dccat tict ga" Bat dmn; thi'iT Cosi ^.;Hi»^i u-j , N e l l a, b la hai so dirarig t h i \;> •AiisW sit^ •i^ni^i K\U ,\v:iky;is\ i\\ UIA * , f(a) rih6|i|hat hogc tam thuc bac ( t i m (o, Zi, de Ui n iv, t i m co, Zc de Ucmnx) hoac dao ham doi v o i bai toan t i m Ui ni v k h i L thay d o i hoac t i m Ucn,.ix k h i C thay d o i thi c6 i, f(b) Ian nha't Pni v) khao sat h a m so de t i m max, m i n ( t i m Zu de UKI n.ix, t i m Zc de UKCI.I.IX) Rieng v A t ,, V D : T r o n g doan [a,b]: •' Buo'c 2: De t i m max, m i n ta t h u o n g d u n g : 6at dang thifc Cosi ( t i m R de • R la hai gia t r i ciia h a m tai hai dau m u t Budc 1: Bieu dien dai hrgng can t i m cue trj la mot h a m cua bien so thay d o i (R, * m s o y = f(x) c6 eye t r i k h i f'(x) = Giai p h u o n g t r i n h f'{x) = gidi •)£^-HC:.; 6:) r r n : i;;' ^ -A 4ac-b" ,, -b a < t h i ym,,x = — = krji xo = 4a 4a 2a U = 200(V) ii>ClionC Phuoitg phdp b' 4a R thay d o i f R thay den lien quan dm cue tri P p = rR = U^R ' ''''' R ^ + ( Z L - Z c f U^ { Z L ^ c f u^ "2|ZL-ZC Pmax 2ZL-ZC RO=|ZL-ZC 13: oa ttffRieh tHiTc v^mt^Tunrren Kcnn vi vj, t^p j - una van men D a n g d o thj c u a P theo R: 0,4f^ ± f - 0 = => f = ( H z ) = > C h o n A Binh R,lt, (z, y.cf (7' Kl luan: pl-idp thu Dc trnnh gidi yhieong trinh bac hai phi'ec tap ta c6 the dung phieang nhu'sau: ':,Mf\ Z L =COL = 10 i = ( H z ) => M = r ( r a d / s ) =: Zc = coC •= 200 => Z , - Z c ' =190(Q) => Z L - Z c ^ ^ = 109(0) Z | = coL = 16 f = ( H z ) => to = ; t ( r a d / s ) - Z c = De t i m hai gia trj Ri, R2 c6 cung P t h i t u P = — = 125 coC •ZL=COL = 20 R'+(ZL-2C) R,R,=(Z,-Ze)'=R(^ f = ( H z ) => CO = ] 0 i ( r a d / s ) : Zc= = 100 (OC - — R + ( Z L - Z ^ - ) - = , theo d j n h h' Viet: 1>V" ^ | Z L - Z C |= ' ^' 80(Q) ^iV ' Z L =COL = 32 R,+R,= f = 80 ( H z ) ^(£, = 1607i(rad / s ) : |ZL - Z r = 30,5(Q) (oC '• "" V i d y 3: M o t doan m a c h x o a y c h i e u mac no'i tie'p g o m tu C = 50/7i (jiF); cuon Tir thj ta n h a n thay: 2Rn cam t h u a n c6 d o t u cam 0,8/7i (H) va bien t r a R Dat vao h a i d a u doan mach dien ap u = 200cosl007Tt (V) (t d o bang giay) De cong suat tieu t h u cua V i d u 1: (DH-2008) Doan mach dien xoay chieu g o m bien t r o R, cuon day mach cue dai thi gia t r i ciia bien t r a va cong suat cue d a i la t h u a n cam c6 t u cam L va t u dien c6 di§n d u n g C mac noi tie'p Biet dien A 120 Q va 250 W B 120 Q v a 250/3 W ap hieu d u n g g i i i a hai dau doan mach la U , cam Ichang Zi., d u n g k h a n g Zc C 280 Q va 250/3 W D 280 Q v a 250 W (voi Zc ^ ZL) va tan so d o n g dien t r o n g mach k h o n g d o i Thay d o i R den gia trj Ro t h i cong suat tieu t h u cua doan mach dat gia trj cue dai P,n, k h i A Ro = Zi + Zc B Pm = U2/R() Huong p = rR = dan U^R R P^ =• 2|ZL-ZC 1^0 = Z[_ - Z(; coC 250 = 200(Q) 2Ro V i d u 2: Cho mach dien noi tie'p g o m cuon cam t h u a n t u cam 0,2/n (H), tu V i d y 4: D o a n mach d i ^ n xoay chieu g o m bien t r a R, cuon day t h u a n cam va t u dien c6 dien d u n g IOO/TI (JIF) no'i tie'p Dat vao hai d a u mach d i ^ n ap xoay chieu 100 V - 50 H z Thay d o i gia trj bien t r a t h i cong suat dat gia t r i cue dai A 71(H) B 1/7I(H) mach d i ^ n ap xoay chieu on d j n h c6 tan so f (f < 100 H z ) Thay d o i R den gia trj 190 Q t h i cong suat tieu t h u tren toan mach dat gia trj cue dai Gia t r i f la C 50 Hz Huong Pmax « 134 R = |ZL - Z c l « |ZL - Z c l = 190 D 80 H z 2c = coC = 100(Q)3>P„ 2Z, -Zr D 1,5/71 ( H ) dan •50 = 100^ 2|ZL-100 •L=-(H) Chon C d y 5: Cho m g t d o a n mach n o i tie'p gom m o t cupn day t h u a n cam, t u di§n c6 dan « 2nf.- C.2/7I(H) Hwang dien CO dien d u n g 0,l/7t (mF) va bien t r a R D i e n ap dat vao hai d a u doan B.40HZ • Chon B (W) bang 50 W D o t u cam cua cuon day c6 gia t r j : =>ChonD A 25 H z i H R O = | Z L - Z C | = 120(Q) Z L =coL = ( a ) Zc = , ;j , '! Huaitgddn D Ro = |ZL - Zc| C Pm = Zi,VZc _ 0,2 = 190 dien d u n g k h o n g d o i va m o t bien t r a R Dat vao h a i d a u d o a n mach m p t dien ap xoay chieu on d j n h Thay doi R thay k h i R = 24 Q cong suat tieu t h y 135 Bo trp kicn tliiic V^t li LTOtl VTV2 tap - Chu VSn tren k^nh Bi€n cue dai t r o n g ctoan mach la 200 W K h i R = 18 Q thi macli tieu thu cong sua'j bc^ng ,• A 8 W B 168W C 192 W Huong Ro = Z, - Z , = 24(Q) - => 2.24 2R {) k h o n g d o i Dieu chinh t r i so dien tro R de cong suat tieu thu cua doan mach dat cue dai K h i he so cong suat cua doan mcich bang dan A 0,85 i'' &jr.m r r 9600.18 y = ( W ) zoChonC 18^+24" ta n (p = V i d u 6: Cho mach dien xoay chieu gom RLC mac noi tie'p T r o n g do, L = 0,2/?! mac vao mang dien xoay chieu c6 tan so f = 50 (Hz) K h i dieu chinh bien tro A ban dau tang dan sau dcS giam dan B tang dan C ban dau g i a m dan sau tang dan Jift-ij im nj- Huong dan /) 'jtyi , Zi - Z r ,!;,;.;;., _ R2+(ZL-Zcr ; • Chon D J2 7t — ^ = ±1 =>(p = ± Rn U 1= A) U VR^(Z,,-Z,)^"ROV5 de dien t r o tang dan thi cong suat tren mach se: unijh " Luc d o n g dien lech pha so voi dien ap la TI/4 • (H), C = I/TT (mF), R la m o t bie'n tro v o i gia tri ban dau R = 20 Q M a c h difoc li.thi'i B 0,5 • COS (ZL-Zcf R^ 144W doan mach RLC khong phan nhanh Bie't tu cam va dien d u n g d u g c giu = 0 ^ U = 40V6(V) U^R P D V i d u 8: (DH-20(>8) Dat dien ap u = Uocosait (Uo va io k h o n g doi) vao hai dau D giam dan Huang dan rrt aiioh jf>l' ^imtii (fb m (Kuril = + (UL - Uc)' => U K „ = |UL - Uc 72 V i d u 9: Cho iri^ch dien xoay chieu noi tie'p g o m bien t r o R, cuon day thuan 61 Z L =coL = ( Q ) ; cam CO cam khang 200 Q va tu dien c6 d u n g khang 100 Q Dien ap dat vao hai dau d o t i n m a c h u = 100 N/2 coslOOnt ( V ) Xac d j n h gia tri ciia bien tro de Zc = coC = 10(Q) cong suat tieu t h u tren doan mach la 40 W f^nx « R o = | Z | , - Z e | = 10(Q) A 100 Q hoac 150 Q C 200 Q h o l e 150 Q Luc dau R = 20 (Q), roi tang dan tiVi cang cang xa gia t r i cue dai nen P .| :.,^1 giam dan => C h g n D "* '" V i d u 7: Cho m o t doan mach RLC c6 R thay d o i Dat vao'hai dau doan macin m o t dien ap xoay chieu c6 gia tri hieu d u n g U k h o n g doi va dieu chinh R = Ro de cong suat tieu thu trcMi nicich dat cue dai K h i dien ap hieu dung •p tren hai dau ciia R l a 45 V T i n h dien ap hieu d u n g giua hai dau R k h i dieu ' chinh R = 2Ru A 56,92 V B , V C , V D 69,52 V Huong dan " K h i R = Ro: P,,,, « R „ = | Z , - Z e i = ^ | U , , - U e | = U R „ = ( V ) U = Juf^o + ( U , - U c f Khi R = 2RQ^JZL-ZC nen: 45^2 = U ' ^ + = 45V2 ( V ) (Gia t r i k h o n g thay doi!) U^R ,t u 0.t • D 200 Q hoac 50,Q i i c,iO ;Vi' fjumig dan •40 R2+(ZL-Zcr \/ Cfc& R, =200(Q) lOO^R R^ +100^ R2 = ( Q ) > Chon p V i d u 10: (DH-2009) Dat dien ap xoay chieu c6 g i a t r i hieu d u n g k h o n g doi vao hai dau doan mach gom bien tro R mac noi tie'p voi t u dien D u n g khang cua tu dien la 100 Q K h i dieu chinh R t h i tai hai gia t r j R i va R2 cong sua't tieu thu cua dogn mach nhir Bie't dien ap hieu d u n g giira hai dau tu dien k h i R = R I bang hai Ian dien ap hieu d u n g giua hai d a u tu ^ien k h i R = RzCac gia t r i R i va R2 la 'A R i = Q , R = 100Q C R i = 50Q,:R2 = 0 Q "y > g f i V i P/> rhn-''-' lif'n U't*^ s.':^'' ;B R i = 40 Q, R2 = 250 Q /; • D R i = 25 Q, R2 = 100 Q Huang dan R ma U'R P = I^R = ff^: B 100 Q hoac 50 Q =,.Ui+(U'L-,U'cr P = I^R = =18VT0 * 56,92 ( V ) ^ R - - ! i - R + Z ^ = => R1R2 = Z ^ = 10000 U c i = 2Uc2 => I , = 2I2 Z2 = 2Z, :=> R2 + = 4(R? + Z ^ ) ^ R2 _ 4R? ^ 30000 • Chon A 136 ,137 => fRi=50(Q) R2 =200(Q) „,:., => Chon C V i du 11: Mot mach dien gom tu dien C, mot cuon cam thuan L va mot bien tro R dugc mac no'i tiep Dat vao hai dau mach dien mot di^n ap u = 100 V2 coslOOrtt ( V ) Khi de bien tro gia trj Ri hoac R2 thi cong sua't tieu thu tren doan mach la nhu Neu Ri + R2 = 100 Q thi gia trj cong sua't bang A SOW B 200W y{ du 14: Mot mach dien AB gom mot tii dien C, mot cuon cam L thuan cam khang va mot bien tro R dugc mac noi tiep Dat vao hai dau mach dien mot hieu dien the xoay chieu u = 120 V2 cosl207rt (V) Bie't rang ung voi hai gia tri cua bien tro: Ri = 18 Q va R2 = 32 Q thi cong sua't tieu thu tren AB la nhu jihau Cong sua't cua doan mach AB khong the nhan gia tri A, P = 72W B P = 288W C P = 144W D P = 576W Huong dan ,1 C 400W D lOOW Tir R R = ( Z L - Z c ) = Ro va P^ax = Huong dan ^2 p = rR = • R'+(ZL-ZC)' •P = - R1+R2 : :,-::., R + (Z| - Zc f = => Ri + R2 = — P cam R,R2=(Zi -Zc)'=R,i ';y r^firin o r i - ) 2R„ Ri +R2 = 3#|i' r' CO t u cam 0,5/7c (H) va tu dien c6 dien dung 0,l/7t (mF) Dien ap dat vao hai dau doan mach u = UA/2 coslOOTtt ( V ) Khi thay doi R, ta thay c6 hai gia trj khac ciia bien tro la Ri va R2 thi cong sua't tieu thu ciia mach deu la P Chon ke't luan dung A R1R2 = 5000 Q2 B R, + R2 = 2U7P C.P P„ D.IOOV2 V y D Pi Vi du 15: Cho mach dien xoay chieu noi tiep gom bien tro R, cuon day thuan Chu y: Khi c6 hai i^id trj Ri va R2 dc cd ciing P thi c6 the gidi nhanh dm vao: P„ suy ra: = 300(W) => P < 300(W) =^ Chon D ^max = 100(W) =>ChonD .'1 va 2R, suy ra: til, ' if ' t (W) =^ChonD 139 v^i f t ^jrmr^TCWt nKMMn-rTV^, jr — « ntt t^p Huong van OiCfT' tan so' f thay d o i d u g c K h i f = 50 H z t h i c u o n g d o n g d i e n hieu d u n g dan mach la A va d i f n ap h i e u d u n g giu-a hai d a u RL k h o n g thay d o i k h i p thay d o i D i e n d u n g n h o nhat cua tu di?n la A 25/7t C^iF) B 50/71 (^iF) C 0,l/7i (|aF) => Huang = 2coL = > CI) = — ? = V = CO, v => Chon B coc 2VLC ' ;' ' = I.ZRT V i du 4: Dat d i e n ap xoay chieu c bieu thirc u = U >/2 coscot (V) (trong d o U va CO k h o n g doi) vao iiai dau A B ciia m o t doan mach g o m doan mach A M noi tiep v o i doan mach M B Doan mach A M c6 cuon cam t h u a n c6 d o t u cam L va bien t r o R mac noi tiep, doan mach M B chi c6 tu d i e n c6 d i e n d u n g C Bie't rang co = (2LC)~^'''' K h i thay d o i bien tro den cac gia t r i R i = 50 Q , R2 = 100 Q va R = 150 Q t h i dien ap hieu d u n g giua hai d i e m A M c6 gia t r i Ian l u g t la U i , U2, U3 Ket luan nao sau day la dung? A U l < U < U M l ; B.Ul>U2>U3 C U l = U > U Huong dan R- + Z f ZC=2Z,=^U„L=IZK,, = U D U l = U = U ,., = UgR=>ChonD ;i = (Z, - Z c = > Zc = Z , R2+(ZL-ZC) u ZL C > ^Zc^ dan , R « ^ ^ ^ ^ =u D 0,2/7t (^iF) ^ ' 50 10-*' (F) ^ Chon B 10071.200 Vi d v 7: (DH-2010) D a t d i e n ap xoay chieu co gia t r j hieu d u n g va tan so k h o n g doi vao hai d a u d o a n mach g o m bien t r o R mac noi tiep v o i t u d i e n co d i ^ n d u n g C G g i d i e n ap hieu d u n g g i i i a hai dau t u dien, g i i i a hai d a u bien tro va he s o c o n g sua't ciia doan mach k h i bien t r o co gia t r i R i Ian l u g t la U c i , URI va coscpi; k h i bien t r o co gia trj R2 t h i cac gia t r i t u o n g u n g n o i tren la Uc2, UR2 va coscp2 Bie't U c i = 2Uc2, UR2 = U R I Gia t r j cua coscpi va coscp2 la: V i d\ 5: Xet mach d i e n A B g o m cac phan t u mac noi tiep theo t h u t u la cupn day thuan cam c6 d o t u cam L, dien t r o thuan R, tu d i e n c6 d i e n d u n g C A coscpi = 1/N/3 , coscp2 = 2/V5 C coscpi = 1/75 Gt)i M la d i e m noi giua L va R, N la diem noi giua R va C Dat vao A , B m o t dien ap xoay chieu c6 gia trj hieu d u n g U k h o n g d o i va tan so'goc co thay doi duc7c K h i Ian l u o t cho co cac gia trj c o i , C02, co3 t h i Ian l u o t dien ap hieu d u n g giOa hai dau M N , giua hai dau A N , giua hai dau M B deu bang U K h i do, he thuc d u n g la: A C03 = C02/>y2 • • , B = coi/2 C C03 = C02/2 = coi/V2 < CO, xay ccing h u o n g d i e n nen coi = '^ci N/2 C02 = 2coi , COSCP2 = 2/75 ' ' D coscpi = 0,5/72 , coscp2 = 1/72 Huang dan i , ' ' i •ifi 7,, J Chon C COSCP2 ^ 4i VLC 2- L, C va CO thay doi lien quan den cpng huong S u y r a 0)3 =2co2 =c)|V2 =:> C h o n D ' ^ Vi du 6: Cho mot doan mach xoay chieu g o m dien t r o thuan R thay d o i dugc, cuon day thuan cam L va tu dien C theo thii t u mac n o i tiep v o i Dat vao hai d a u doan mach mcit dien ap xoay chieu co gia t r i hieu d u n g 200 V -^ ^r Ri coscpi = (!), l a m cho U[^(j = U nen Z, = IZ^^ =>o)3 = 50 Z = 1/73 D C03 = 2co2 = coi 72 Huong lam cho U,^L = C03 = I = ^ B coscpi = \lsl5 , coscp2 = • • ZL = Z c « L = Dieu kien cgng h u o n g : coC IZL=IZCI"L = I R A C L,r M N B coC 151 thufc V^t HLTDH trcn kcnh VTV2, u t^ip - Chu Viin Bicn U (R + r ) + ( Z , - Z ^ f R + r U R + r =r p r = I - o ( u Khi L, C va lo thai/ doi thi P,,,,,,, = — u R +r U p Cty R + r ^- R + r U U „ R +r R +r y U 0,1/Tt Khang Vi^t Z, = Z^- chieu giua A va B co gia t r i hieu d u n g va tan so !u6n khong d o i Ban dau R^+Zf L = L I , cho R thay d o i k h i R = Ri thi cong suat tieu thu cua mach A B Ion nhat R^ + Zi |Z,,-Z,.| = V i du : Doan mach noi tiep g o m cuon day co dien t r o thuan Q, c6 tu cam l i VVtl cam L thay dcii duoc, mot tu dien C va mot bie'n tro R Bie't dien ap xoay la (Pi)ni,ix = 92 W Sau d o co d i n h R = Ri, cho suat tieu thu cua mach A B Ion nhat la A W Gia t r i cua D 92 W "( , Khi C va L, (0 thay d o i t h i , P,,,,,, :• ; ^ , = —^ bang ' K h i R thay d o i thi P,,,,,I = 2R| thi cong L = L2 (P2)max C 184 W Huong dan H , tu dien co dien d u n g C thay doi va mot ampe ke'co dien tro rat nho Dat vao hai dau doan mach m o t dien ap V - H z Thay d o i C thay d o i , k h i L (P2)m,ix B W R+r R + r MTV V i du 3: Cho doan mach dien khong phan nhanh g o m mot cuon cam co t u z, U V TJytlll , ' ' ^ ' v ' max2 = 2Pniaxi , , = 184(W) ^ Chon C thi so chi cua ampe ke'la cue dai va bang A Gia trj cua R va C la , A R = 50 Q va C = Hn mF B R = Q C R = 40 Q va C = l/n mF D • R = 40 va C O va = l / n mF V i du 4: M o t cuon day mac noi tiep v o l tu dien co dien d u n g thay d o i d u g c roi mF mac vao nguon dien xoay chieu co bieu thuc u = Uocoscot (V) Thay d o i dien C = I/TT d u n g cua tu dien de cong suat toa nhiet tren cuon day dat cue dai t h i k h i Hu'6n Z L = Zc ^ Z = r ' U I,,,,^ = — = Uo r rv2 r ^+(7,-7-) ^+(ZL-Zcr Chon D = l ( A ) = > R + r = = > R = 40(Q) V i du 2: Cho mach dien noi tiep g o m cuon day thuan cam co d o tu' cam L tiia\ doi du-OQ t u dien co dien d u n g l/(6Tr) (mF) va dien tro 20 Q Dien ap dat vno hai dau doan mach u = UocoslOOjit (V) Xac d j n h d o tir cam ciia cuon day dt' U c = l Z c - • ; - ^ Z c = U o - > Z c =2V2.r.; , , v „Opl^,^,.a, rV2=>ClionC Uo /TTTT Ucd=IZea=;;j^V' V i du 5: Mach ditMi Uo / T T T T _ U „ 8, - - ^ ' ,.v: >^-' rv xoay chieu ncYi tiep gom dien tro thuan R, o n g day thuan dien ap hieu d u n g giua hai dau d j a n mach chua RC dat gia t r i cue dai cam CO cam khang Zi = 2R va tu dien co dien d u n g C thay d o i dugc K h i A 0,6/K ( H ) thay d o i C den gia t r i Co thi cong suat tieu thu tren mach dat cue dai la B 0,8/71 ( H ) C 0,4/Tr ( H ) D , 0,3/71 ( H ) Huong dan U KC \ R" + Z^- = mnx Z , -Zr R^+(Z,-Ze)^ , • coL = WC ,0,6 => L = ( H ) =>Chon A ^ 71 =0 Pm.,x = 100 VV K h i thay d o i C den gia trj bang 2G) thi cong sua't tieu thu tren mach la : A 25 W B SOW R^ = \Zy - Z ^ - A" C 60W.| Huong dan A' P.iiax Chu \j: Khi R thai/ do} thi P,„_,^, = 152 B 3Uo ' i, '-.i , Huong dan J-' U ' ( D SOW cong hudng Zco = Z L = R \^:'MnMKU.r: • • 152 tS trff kI6n thitc V$t li ITUtI m» Kerm-viVJ C = 2Co Z r = - Z r o = R =^ P = t^p u - unu van aieir R2+(ZL-Zcf 2R = 50(W) :=>ChonD d u 6: (DH-2009) Dat dien ap xoay chieu c6 gia t r i hieu d u n g 120 V , tan so 50Hz vao hai dau doan mach mac n o i tiep g o m dien t r o t h u a n 30 Q, cuon cam t h u a n c6 d o t u cam 0,4/7t ( H ) va t u dien c6 d i e n d u n g thay d o i dugc Dieu chinh dien d u n g cua t u dien thi dien ap hieu d u n g giOa hai dau cuon cam dat gia t r i cue dai bang A 150 V , B 160 V C 0 V ; A ' h G Huong U, D 250 V 7R'+(ZL-ZC)' mach no'i tiep g o m dien t r o thuan 200 Q., cuon cam t h u a n c6 d o t u cam 25/(36TI) H va t u dien c6 dien d u n g 10 VTI (F) C u o n g d o h i ^ u d u n g d o n g dien qua mach la 0,5 A Gia t r i ciia CO la p^, 15071 rad/s j , B 507i rad/s : U ti'^'- 200^ + c o L - dan Z L =160(V) ^ C h o n B VR^+0 = I Z , =• y i dV 9: Dat d i e n ap u = 100 N/2 coswt (V), c6 co thay d o i d u g c vao hai d a u doan d u 7: Dat d i e n ap 150 V - 50 Hz vao hai dau doan mach mac no'i tiep g o m cuon day c6 d i e n t r o thuan R , c6 d o t u cam L va t u d i e n c6 d i e n d u n g C Thay d o i C d e d i e n ap gii>a hai dau cuon day dat gia t r j cue dai t h i gia t r j d o B lOOV C I O O V V Huong U,,=I.Z,,= D 150N/2V r + ( Z L - z c r • = 0,5=>(oL = ^ coC coC l0/(247i) mF D e hieu dien the hieu d u n g giua hai dau doan mach chua L C A 60 H z B 50 H z ULC=IZLC=- -—TT^ ^ = 60(Hz) U L = 200 =:> U c = 0 ( V ) =5 Chon A ' '' ' ' ';' tan so f2 = 120 Hz, he so cong suat la 0,5 N/2 tan so b = 90 Hz, h ^ so cong !' B 0,486 C 0,625 Huong dan d o g i a m d a n d i e n d u n g t h i goc lech pha giua d i e n ap tren cuon day va dien A 7i/2 va k h o n g thay d o i I'l i)( B 7r/4 va sau d o tang dan \, Jin Huong = coL = ( Q ) dan r tancp = ZL-Z, = i ^ = -l=>(p = — , ' ,j j ;) vnivi i , f = f2 = 120 (Hz) = 2fi => , ^ ma coscp, =0,5V2 hay Z'c =0,5a R R C 7r/4 va sau d o g i a m dan D 71/2 va sau d o tang d a n D 0,781 ,,,„,vj u';^;vn>uh wm f = fj = ( H z ) = > c o s ( p , = = > Z L = Z c = a ap toan mach luc d a u la 54 Chon A ' chieu CO tan so thay d o i dugc tan so fi = 60 Hz, he s o c o n g suat bang mot dien ap xoay chieu o n d j n h c6 tan so 50 H z L i i e d a u C = 0,l/7c (mF) sau (Pj,£) - (p = — => Chon D = Zc ZL 2nJ- suat cua mach bang =100(Q) = = « ZL - Zcl ^ D 40 H z / ? dan >2+(ZL-ZC) A 0,874 Zci=- C 55 H z Huong tiep v o i m o t t u d i e n c6 dien d u n g C thay d o i Dat vao hai d a u doan mach ] •{O = 1207r(rad/s) =:>ChonD I6n 247t Vi d u 11: Mae vao doan mach R L C k h o n g phan nhanh m o t n g u o n dien xoay d u 8: M o t cuon day c6 dien t r o thuan 50 Q, c6 d o t u cam 0,5/7r ( H ) , mac noi ZL ,,p,,.„o^ dat gia t r i cue tieu thi tan so bang UK = U = 150(V) >0 U ? d = U f , + u2L=2502 D 12071 rad/s di^n xoay chieu R L C mac theo t h u t u d o c6 R = 50 Q , L = l/(67t) H va C = dan = max o Z L = Z(2 = > Vi d u 10: D a t hieu d i e n the xoay chieu c6 f thay d o i vao hai dau doan mach f = UVR '• C IOO71 rad/s Hudngdan b3ng 250 V Luc nay, d i e n ap hieu d u n g tren tu bang A.200 V Z ' l =2a = 0,572: R2+(Z'L-Z'cf - , ' ! v ( >R = l , a VR2+(2a-0,5a)2 ^ Z"L=l,5a f = f = ( H z ) = l,5f, • COS(p3 = Z"c = R 7R'+(Z"L-Z'C)' 2a 1,5a c 1,5a * 0,874 =>ChonA 2a 155 Bo trf> kien thiic V^t II LTDtl trcn henh VTV2 t^p - Chu Van Bien^ V i d u 12: Goi ii, LIK, U I va I R Ian l i i o t la dien ap Cach 2: D u n g gian d o vec to tiic tiiai giua hai dau macii, liai dan diC'ii tra R, hai dau cuon cam thuan L va hai dau tu ' "' dien C cua doan mach xoay chieu noi tiep Ban dau mach c6 tinh cam khang, sau i ' - ' ^ - ' ^ g i a m dan tan s o ' d o n g dien qua macii thi dai ; :x|i l u g n g giam theo la lech pha giu'a A u va uc B u i v a u i ^ C D UI va u j b n m nr"h UK ir»|- : , "j ^ > ' Huong dan ^'c vr,o; N Sau f giam thi cam khang giam dan nen U quay vc phia T nghia la Ta c6: sin a = Chon A V i d u 13: M o t mach dien xoay chieu gom RLC ghep no'i tiep Ta dat vao hai U pha h o n d i e n ap u N e u chi tang dien d u n g C t u tir t h i h ^ so cong suat cua C g i a m nhe roi tang .> n R ' ' B tang j- D giam ')7fVn£ K i l l t Ant; ('111)/(^-= f;i:nii n r n (/.(^' /.[)" ' Kiiiiil V He U sin p sina U R2 „„o _^ ; ,, I , T => U UR,_^- ^ , , uJR^ + z »6b ifirt R uz, UZ, 7R'+(ZI - Z e f ^(R-+Z^.)-2ZeZL+z'L A,,'f ^ xj L., + Z^^ = Z C Z L ^ ZL '' •B b^+c^ ,j,«,^^^,_,„ U R - U c ( U L - U c ) » h =b'c' o ' qua: =U,.(UL-Uc)ob2 - = max i j y W l n = - y - ^ 1 ij, =ab' U?cos(p taiig JR-+(Ze-ZO^,,QJ.§,;-•;•^- Z AN •=>U| = sin a Khi do: ' AN U Huong dan Cl)S(p = — = • sinp "("-S A k h o n g thay d o i A M _ Z,,M A p d u n g d j n h ly h a m stYsin cho tam giac A N B : dau doan mach m o t dien ap u = UusinlOOTit (V) H i e n tai d o n g dien i sum mach ban dau se U,'RC Uc '^•'vl it/'i :(.'; Luc dau mach co tinh cam khang nen U nam tren I lech pha giua u va uc g i a m O > — va uc • I M W ^ "c^ • ' ' V i d u : Cho mach d i e n noi tiep g o m cuon day thuan cam c6 d o t u cam L thay d o i duoc, t u d i e n ccS d u n g khang 60 Q va d i e n t r a t h u a n 20 Q D i e n ap dat , ax + b\ c = mm x = h 2n vao hai dau doan mach u = 20 Vs coslOOTit (V) K h i cam khang bang Zi t h i i Z| dien ap hieu d u n g tren cuon day dat gia trj cue d a i R-+Z^ Ui-irax Gia t r j Zi va U: m.nx Ian l u o t la Thay bieu t l i i i c Z i vao U , — tinh ra: U| , >^+(Z,,-Z,.)^ 156 R A 200/3 Q va 200 (V) C 200 Q va 200 (V) B 200/3 Q va 100 (V) ^ D 200 Q va 200 (V) , ; , 157 B6 trp klen thiic V$t I I L T D I tren kcnh VTV2 t^p - Chu VHn Bl&n V i du 4: (DH-2009) D a t dien ap u = Uncoscot vao hai d a u doan mach mac n o i j'/r.;;) Huong dan T r u d c k h i lam bai nay, chung ta phai nhuan n h u y e n p h u o n g phap da noj tie'p g o m d i e n t r o t h u a n R, tu d i e n va cugn cam t h u a n c6 d o t u cam L thay tren Va luc ta k h o n g nen lap lai cac buoc tuan t u m a nen ap d u n g d o i dugc Bie't d u n g khang cua tu dien bang R>/3 D i e u c h i n h L de dien ap t r i n h giai nhanh nhir sau: hieu d u n g giOa hai dau cugn cam dat cue dai, k h i d o u A d i e n ap g i i i a hai d a u d i ^ n t r o l§ch pha n/6 so v o l d i e n ap giOa hai dau L max doan mach R ;X ; ' T ' ' ^ ' • ^ ' ' n-,?:; B dien ap giOa hai dau tu dien lech pha n/6 so v o i d i e n ap gii>a hai dau ION/TON/ZO^ '-'Lmax Thay so vao ta dugc: z, = +60^ 20 20^ + 60 200 60 d o a n mach = 100(V) > Chon B j.^ M/,,,,, • D d i e n ap giOa hai dau cugn cam lech pha n/6 so v o i d i e n ap g i u a hai dau doan mach l^idndovectode'tiinnhniilike'tqiid 5:.j,j;!:p.i/:,i',,rj' Huang dan tan a = — ^ = —!^ = - = UK R V3 u = UV2 coslOOiit vao hai dau doan mach ^ e a c h 2: U , « t u cam L thay d o i dugc D i e u chinh L de bang 100 V va d i e n ap hieu d u n g hai UL max t iJ^^^•, r Hu&itgdan => Chon A •-•fei''•s(y'':,.Ji-pt J-^)'^-^'-' 1(l^y.>4 \J:.~,-.;,ijl:',[i , ''i j ' , d o i dugc, t u dien C va dien t r a R Dien ap dat vao hai d a u d o a n mach u = 100N/6 coslOOnt (V) K h i dien ap hieu d u n g tren cugn day dat gia trj cue dai Ui,M.ix t h i d i e n ap hieu d u n g tren tu la 200 (V) Gia t r j UIMM • •* ^ L m a x U dugc: =5 Chon C 158 B ( V ) " URC' 3P •yvJ-UUi:: : C.300(V) D 200 (V) :k:H&i B 50 Q C 150 Q l i i : : D 200 Q ; / C r ' ' ' K ' ^ ' ' H u o n g dan f Pmnx » cong hucing => Z i = Zc R + Zr ZL2 = Z L I + 50 nen: Zc ^.Zr-^ 50 = ^ " " l " " ^ ^ =^^c = 200(Q) =^ Chon D Zc va cugn cam t h u a n , d a n g xay cgng h u o n g Neu chi tang d g t u cam cu£ cugn t h u a n cam m o t l u g n g ra't nho t h i d u n g he thuc l u g n g t r o n g tam giac v u o n g b^ = a.b' ta 3.100^ = U, ( U L - 0 ) => U L = 300(V) V - • >'^':-^l-:;-''K;''^;:;.: i/ A 100 il V i du 6: C h o n phat bleu SAL Mach d i e n n o i tie'p g o m d i e n t r o thuan, t u dien la Hwang dan = U , ( U L - Uc) V3 mach d a n g dat gia trj cue dai ma tang cam khang t h e m 50 Q t h i dien ap tren K h i L thay d o i : ' ' V i dy 3: Cho mach d i ^ n no'i tie'p g o m cugn day thuan cam c6 d o tir cam L thay A lOO(V) Z^- hai d a u cugn cam d a t cue d a i T i n h d u n g k h a n g cua t u ^:':•'••;•!';•-••• U - =100(100-36) =>U = 80(V) =- L = _L R day t h u a n cam L c6 the thay d o i gia t r j dugc K h i cong sua't Lieu t h u tren D 48 V ap d u n g he thuc l u g n g t r o n g t a m giac v u o n g b^ = a.b' ta dugc: U - = U | , ( U , _ - U f ) R •••• V i dy 5: Cho d o a n mach xoay chieu RLC mac n o i tie'p v a i R = 100 Q va cugn i ' ^ C 64 V • tan cp = R'.ZI => (p = — > : d i e n ap som pha h o n i , U K la n/6 => Chon A gia trj cue d a i t h i thay gia trj cue dai d o : B 136 V Z, = ^ Zc d i e n ap hieu d u n g hai dau cupn cam dat Vv ( f vM o i J • =>« = - = > Chon A • mac no! tie'p g o m dien tro thuan R, tu dien CO dien d u n g C va cupn cam thuan c6 d o : '•\siAiS}\h Cach 1: D u a vao gian d o vec t o ta nhan thay u s o m pha h o n UK la a va V i du 2: ( D H - n ) Dat dien ap xoay chieu dau tu d i e n bang 36 V Gia t r j cua U la /v; C t r o n g mach c6 cgng h u o n g di?n Chil y: V&i cac bai toan chi lien quan den cac U hoqc cdc lech pha ta nen dit)i0)i»vOt;i = 'K \ f\n,- B V ; ' r I • - i • Bo tr^ hicn tliiic V^t li LTDtl tren henh VTV2 t^p - Chu VSn Cty Trmn nrv Bien Huong dan Huang dan Dieu kicn etc xay cong h u o n g va U i m i x Ian l u g t la: Khi Cong h i i d n g Z] | = ZQ U Zc U[,T,ax => U J UK(^- nen URC tre pha h o n u la 7t/2 D o d o : (p = -7i/4 V i U K C = U = 100 V nen tarn giac A M B v u o n g can tai A , suy tam giac A E M = z.•c R2 => Z^i < : D i e u cc ngiiTa la kiii Z^ dang cong h u o n g ne'u tang L thi se tie'n den gia t r i Z1.2 ngiiia la U L tang dan \if-f den gia t r j cue dai => Chon D t l w 'rA>h ; _ Uc = U R => Zc = 100 Q => C = 0,1.10,-3 -(F) =>ChonC a)Z| 7C V i d y 9: Cho doan mach RLC mac noi tiep, v o l cuon cam t h u a n cc d o t u cam L V i d u 7: Cho mach dien xoay chieu RLC co cuon thuan cam L c6 the thay d o i gia t r i duoc D u n g ba v o n ke'xoay chieu c6 dien t r o rat Ion de d o dien ap jf.l: hieu d u n g tren m o i phan tir Dieu c h i n h gia trj cua L t h i thay dien ap hieu thay d o i d u g c D i e n ap xoay chieu giua hai dau doan m a c h l u o n o n d i n h Cho L thay d o i K h i L = L i thi dien ap hieu d u n g giCra hai ban t u dien c6 gia trj Ian nhat, dien ap hieu d u n g giOa hai dau dien tro R bang 220 V K h i L = L d u n g cue dai tren cuon cam IcSn gap Ian dien ap hieu d u n g cue dai tren thi dien ap hieu d u n g g i i i a hai dau cuon cam c6 gia t r j Ion nhat va bang 275 dien tro H o i dien np hieu d u n g cue dai tren cuon cam gap bao nhieu Ian V, dien ap hieu d u n g giua hai d a u dien t r a bang 132 V L i i c dien ap dien ap hieu d u n g cur dai tren tu? A Ian B Ian hh.-tim ©^'^ '^V^ t f xyi w t C Ian Jfoi D 2/^/3 Ian hieu d u n g g i u a hai ban tu dien la A 96 V u /" u Uc = max => Cong hucing => U R = U = 220(V) =u ULH,., « u URC ul + U?,c = U - + uf, + U^- = => 275^ = 220^ +132^ + Uc => Uc = 99(V) => Chon D b Khi C thay doi tint dieu kien Ucm l.mav R Cach : It Theo bai ra: Ui.m.ix = U K i n i x hay — ^ + R\3 D 99 V C 457 V Huong dan K h i L thay doi t h i U ' B 451 V Huong dan m O VVn Kbang Vl^t Uc = IZc = R^.(Z, V i d u 8: M o t doan mach A B g o m hai doan mach j c;, R u |(R'+Z^)-^V-2ZL-^ + ^^^^ + bx + c A M va M B mac noi tiep Doan mach A M c6 b ax" + bx + c = o x = dien tro R = 100 Q mac noi tiep v o i tu dien c6 ' dien d u n g C D o a n mach M B c h i c6 cuon ^(R' + Zf,)-2ZcZi,+Z^ f U Uc = •Chon D hii ' cam t h u a n v o l d o t u cam L thay d o i d u g c D a t dien ap u = 100 V2 cos(1007rt + n/i) ( V ) • ' vao hai dau doan mach A B D i e u chinh L de dien ap hi^u d u n g tren cuon cam cue dai, k h i d o UAM = 100 N/2 cos(1007xt + ep) ( V ) Gia trj cua C va cp Ian l u g t la A 0,2/71 (mF) v a - i / B 0,l/7i (mF) v a - T C / C 0,1/71 (mF) va -7t/4 D 0,05/7t (mF) va -7i/4 l':iv„iU.,i B A UZc UZc —= 2a ZC = max -I =oZc = » R^+Z^ ''''''' R ' + Z ^ UZc Thay bieu t h u c Zc vao Uc = , yR^+(ZL-Zc) t i n h ra: U C m a x ~ U^R^ + ^ Zl ^ach 2: D u n g gian d o vec to Ta co: sina = AM Z^M AN ZA N R A p d u n g d i n h ly ham so sin cho tam giac A N B : sinp ^ sina U , = - ^ ^ = max«P = 90"=^0lURL sina 161 B6 trpkiSn thiic V4t li LTDH tr€n kenh u t^pZ-Chu VTV2 Bicn V^n C/!M V- ^(^w tiitjch CO nhieu dien tra thuan thi dp dung cong thi'ec tren can thay u R = l R - sin a Khi do: AN' Y j du 2: C h o mach dien no'i tiep g o m dien t r o 30^/2 cuon day c6 d o tir cam = MN.NB « = ZMN-ZNB » R' + = Z^-Z, => Z ^ = Z, 0,3-42 In ( H ) va dien t r o thuan 30>/2 Q va t u xoay c6 dien d u n g thay d o i C D i e n ap giCra hai d a u doan mach: u = 240\/2 coslOOTtt (V) K h i C = Cm t h i dien ap hieu d u n g giira hai dau t u dien dat gia t r i cue dai U m Gia t r j cua Cm va Urn ian i u g t la A ( H F ) v a l ( V ) clnjfj / i d noi.-'i H.i?- Chon C Vi dy 6: Mach dien R L C noi tiep dang xay cong huang Neu chi giam dien dung tu dien mot lugng ra't nho thi A dien ap hieu dung tu khong doi B dien ap hieu dung tren dien tro thuan khong doi C dien ap hieu dung tren tu tang D di^n ap hieu dung tren tu giam , , , Hwang dan Cong hadng : Z,-, = Z , Ucmnx khl : Zc2 = — = Z,, + > Z ci -I Liic dau: Z ^ = ZL < ^ ^ Uc Clion C '» • ,\ Vi du 8: Mach dien no'i tiep gom cuon day c6 ty cam L, di?n tro thuan R va tu xoay CO dien dung thay doi C Dien ap giiia hai dau doan mach: u = 30>/2 coslOOTtt (V) Dieu chinh C de dien ap hieu dyng tren ty dien dat gia tn eye dai va bang 50 V Khi dien ap hieu dung tren cuoc day la A.20(V) B.40(V) C lOO(V) D 30 (V) Huang dan U = OR + , + O r = OR, + O r ^ R L^ U e w^« U l U ^ u RL n , T , , =7U^-U^ =40(V) =>ChonB Vi dy 9: Mot cuon day mac noi tiep voi ty dien c6 dif n dung C thay doi duoc roi mac vao nguon dien xoay chieu u = Uocoscjt (V) Thay doi C de dien ap hieu dung tren tu circ dai thi gia trj eye dai diing bang 2Uo Dien ap hieu dyng giiia hai dau cuon day liic la B 3Uo A 3,5Uo C U o V ; D 72 Uo Huang dan U = URL + U C Ucmax«UlOR, => Chon C Cty B o trf/ Men tliirc Chu V^t I t L T B l l t r e n henh VTV2 y: Khi thai/ dot C dc Uomx tin dong dicn sc i:6in pha hun dien ap Id a cho: R tan a = - Tram JVTV D VVHKhang Vlft t^p - Chu V^n B i g n \ Dat vac A B m o t d i e n ap: UAB = 120 s/Z costOOTtt ( V ) D i e u c h i n h C de tong dien ap h i e u d u n g (UAM + UMD) dat gia trj cue dai T i m gia trj cue dai cua tong so U, V i d u 10: Cho mach d i e n xoay chieu noi tiep g o m dien t r o R , cuon day thuan cam va t u d i e n c6 dien d u n g thay d o i D i e n ap giira hai dau doan mach c6 A 240 V - B 120 V3V C.120V •• D I20V2V Huong dan gia t r i hieu d u n g U K h i dien d u n g thay d o i de d i e n ap hieu d u n g tren tu cue dai t h i d o n g d i e n qua mach sam pha hon dien ap g i i i a hai dau mach la 7i/3 D i e n ap hieu d u n g tren tu eye dai la A.U B U Iv'' - - i ' , ' iA C.U^/3 5,u.,\ii.' i u, v.A AME = 6O'' D.2U/73 =:> Co t h i Zc cang xa v i t r i cue dai nen Uc d j n h (pu Thay d o i C de dien ap hieu d u n g tri^n t y cue dai vie't bieu thuc dien g i a m , n h u n g Zc tie'n dan den v j t r i cong ap tren doan A M va M B liic h u a n g nen I tang=> Chon C ,, doi ta da diing dink ly ham so sin: C J Huang dan ' '" >!/! Chii y : Khi dung gidn vec ta detim ^ ' = max Khi U ^ u = I Z ^ M = U a b c g.^^ sinB sinC Neu hai todn yen cau titn ' b+c , B+C B-C sin cos 2 V i du 12: D o a n mach A B n o i tiep g o m hai doan mach A M va M B D o a n mach A M la m o t cuon day c6 d i e n t r a thuan R = N/3 Q Z L = Zc Mcich c6 cgng >^+(Z,-Zcf h u a n g nen ve gian vec to n h u h i n h b _ c _ b+c sinB sinC sinB + sinC va d o t u cam L = 0,4/7t H , doan mach M B la m o t t u dien c6 dien d u n g C thay d o i dugc, C c6 gia trj h i i u han va khac k h o n g ^ Uimax L thay doi hoac Ucmax C thay dieu kien de (b + c) = max thi ta dp dung tinh chat cua day ti so bang nhau: a sin A ^^^ T u g i a n vec ta: cos^^^^ = => ^3^1^ = 60" => UAB la n/3 (pu = =^ L »- C* tre pha b a n UAM -n/2 hay u^[j =]00V2cos lOO-nt-^ ( V ) , / 200// U, / 100 Hinh B Hinh no trp kian thac Vft If LTDH Iren kenh VTV2 t^p - Chu VSn Blen K h i Ucnwx => U ± U R L ' ve gian d o vec to n h u h i n h • Ctj' TnaiH MTV D VVH Khang =^ ( Z L I A M = 100tan60° = 100V3(V) u^,^ s6m pha hdn u l a = 100V6cos 0 t - ^ + cuon cam k h i Z L = Z L I gap hai Ian k h i Z L = ZL2 Gia trj Z L I bang jm -r^'^-mt^ B.0,7572 A 50Q B 150Q C 20 Q Huang p, = P2 C 0,75 Huang =4 Z, = U u = U L2 D.2V2.^^,;r dan ZLI R + Z f =3Z, = > Z , = R UZLI: VR'+(ZLI-ZC)' =20 (n) M./ >^+(ZL2-ZC} Chon C i 4/7C ( H ) va k h i L = L2 = 2/71 (H) t h i mach d i e n c6 cung cong suat P = 200 W Gia t r j R b a n g A 50 Q B 150 C 20 Huang H a i gia tri L, C c6 cung I, P, U R , U i , Uc Z L I + ZL2 P, = P2 =^ Z, = Z2 => Zc =:i a Khi L thay doi hai gid tri L i va L2 c6 cung I, Uc, UR, P thi Z, = Z2 ^R^ + ( Z L , -Zcf=^R'+ :^(ZL,-Ze) = Z] = Z2 (Z,,2 - Zc f -(Z,,-Ze)^Zc=^i4^ R R — = Z; Z2 COSip, = C0S^P2 9] = P =• • ' : U^R R^ + ( Z L I • 200 = • - Zc)' fi 1) Zc = -^P2 ra: ZLQ = + ZL2 dan = 300(Q) " 200'R , hoac L = L2 = L i t h i c u o n g d o hieu d u n g qua m a c h n h u n h a u T r i so'Li la Huang i>i 168 =P2 =>Zi = Z +(z,, -Zcf D l,5/7r ( H ) dan = VRH(ZL2 -Zc)' ' , „ Z L I + Z L2 URmax, Pmax) tkl ZLO = Zc TU dO SUy L, + L h ="—;— C = 100/7t ()aF) v a cuon day t h u a n cam c6 d o t u cam L thay d o i N e u L = L i C 0,5/71 ( H ) R = 100(f^) =>ChonD + ( 0 - 300)^ j^i^- ^.^^ huang (Lmx, Uomx, ' d a u doan mach mac n o i tiep g o m d i f n t r o t h u a n R, t u d i e n c6 d i e n d u n g B l / i ( H ) D 100 Q \ Chu y: Khi L thay doi hai gia trj Li va Li c6 ciing I, Uc, UR, P thi V i dvi 1: D a t d i e n ap xoay chieu u = UocoslOOTct (V) (Uo k h o n g doi) vao hai A.2/7t(H) : => Z L I - 2ZL2 ap xoay chieu c6 bieu thuc u = 200 V2 coslOOTtt ( V ) Thay d o i L , k h i L = L i = 2^y2 - = 0,75V2U => - = 0,7572 =^ Chon B R UZL2 = 2.^ k h o n g d o i ; L t h u a n cam va thay d o i duoc D a t vao hai d a u d o a n mach dien _RJ U^R^+Z^ •z = dan V i d y 3: M a c h d i e n xoay chieu g o m ba dien t r o R, L, C mac no'i tiep R va C R U^R D lOQ Z2 => Z L I + Z1.2 = 2Zc = 30(n) ZL2=io(n) = U Cmax Chon C c u o n g d o hieu d u n g qua mach n h u n h a u D i e n ap h i ^ u d u n g a hai dau d o i t h i d i ^ n ap hieu d u n g cue d a i tren R, L va C Ian l u g t la x, y va z N e u z/y Z (H) thay d o i D i e u c h i n h L de cam k h a n g Ian l u g t la Z i = Z L I va Z L = ZL2 t h i • " A M =200V2COS i o o t - : ^ - : ! i ( V ) ^ R, cuon cam t h u a n L va t u dien c6 dien d u n g C thay d o i d u o c K h i C thay ^ 71 0) ^j(V) V i dv 14: Dat d i e n ap xoay chieu vao hai dau doan mach no'i tiep g o m d i e n tro = 3thiz/xbang 0,5 Z , + 3ZLI = 200 => Z L I = 50(n) => L , = t r o t h u a n R, t u d i e n c6 d u n g k h a n g 15 Q va cuon cam t h u a n c6 d o t u cam L t r i pha hdn u ^ g la - s A.2^/2/3 = 2Zc = 200 (fi) + Y i d u 2: D a t d i e n ap xoay chieu vao hai d a u ddan mach mac n o i tiep g o m dien MB = - i ^ = 200(V) cos60" "MB - Z c ) = - (ZL2 - Z c ) ^ Vl^t , 2) Z,=Z2 R R Zl ~ Z COSCPi = C0S tPl = -"''•'•• 169 BA' trf> hlSn thdrc V^t If LTt>tl trcn kenh VTV2 t^p - Chu V^n BIcn Cty TNtin MTV DVVH V i d u 4: Cho mach dien xoay chieu tan so 50 H z noi tiep g o m cuon day thun'n ' vao hai d a u doan mach mac noi tiep g o m dien hai gia trj khac cua L la V3 / n ( H ) va SI tro t h u a n R, t u dien va cuon cam t h u a n co cam gia t r i hieu d u n g n h u n g gia trj tuc thoi c6 piia ban d a u l i o n k e m 27i/3 k h a n g Zi thay d o i Dieu c h i n h Zi ian l u g t bang Gia trj cua R va Zc ian l u g t la 15 a, 20 Q., 32 Q, 38 Q, 41 Ci va 65 Q thi c u o n g d o A 0 Q v a 0 V Q , ' C 200 Q va 200 N/3 Q gj•;!; dan ^•'34Zu;/L2] rl D h =-1 =^(ZL-Za) = -(ZL-Zc2)=>ZL = R Zi = z , => • R Z c i + Zc2 • COS(p] =COS(P2 • 9i =-92 V i d u : (DH-2010) D a t dien ap xoay chieu c6 gia trj hieu d u n g k h o n g d o i , tan SO 50 H z vao h a i d a u doan mach mac n o i tiep g o m dien t r a t h u a n R, cuon '+(ZL-ZC2)' V i d u 5: D a t dien ap xoay chieu u = 100 -Jl coslOOnt (V) vao hai d a u doan mach A Z'L4=42(Q) doan mach d e u co gia trj bang Gia t r i cua L bang • A 1/(271) H 1) Dt'so sdnh P.i va P4 ta c6 the dung phumig phdp "gidng B.2/71H C 1/(371) H Huang day" nhir saii: Tif Pi ke diimig song song v&i true hodnh „ ne'u Pi tren day thi P4 > P.? vd ne'u duai day thi P4 < P.3 Zci „ : - _ = 400Q;Zc2 = - = 200Q dan ' ^i"'*'-' C6cuni;P=^Zi=Z7 ^-^1=^2 , D.3/7tH , Z^i + £ ^ Zc2 2) Dethn cdng suat Ian nhd't sd'cdc cdng suat da cho, ta chi can so sdnh hai g'l^ tri gan dinh nhat bhngphucmg phdp "gidng day" , -fi„^.^^.,^ , ^u^/ .1007iL = 300 = > L = - ( H ) •ChonD I7n \tBiin iV'>hH.;-' 171 T^jrr/mrrTvrviJinimntang BS tr a = 7:/3 • COS(Pi = cos 92 => (Pl = -^2 =^ (p2 = - a < (Pi = - a < 200-100 (khiQC2) => v ; / ; ^ T : i c ' ; s / D 0 Q C 100 Q dan ftpi = + a = 300(Q) (P2 = - a Z c i + Zc2 = 200(Q) _ 2C^C2 cp2 = + a > Zl — Z p i > tancpi = — !=^ = t a n a R ^ 7t „ 100 = t a n - =i> R = Chon B S V i d y 6: Cho mach d i3e n xoay chieu tan so 50 H z noi tiep g o m cuon day thuan R cam L, t u d i e n c6 d i e n d u n g C thay d o i d u g c va d i ^ n t r a R = 100 Q Co hai (C cang nho t h i Zc cang I o n l a m cho U cang tre va n g u g c lai!) gia t r i khac n h a u ciia C la Ci va C2 = 0,5Ci mach c6 c i i n g cong suat toa nhiet Dong dien hai truvng hap lech pha la a n h u n g d o n g d i e n lech pha la n/2 Gia trj ciia Ci la B 25/7t |.iF A 100/7t V i d u 3: Dat d i e n ap xoay chieu o n d j n h vao hai dau doan mach mac n o i tiep Huang gom d i e n t r a t h u a n R, cuon cam thuan c6 t u cam L va t u d i e n c6 dien d u n g C thay d o i d u g c D i e u c h i n h dien d u n g C de d u n g k h a n g cua t u bang 100 Q hoac 300 Q t h i c u o n g d o hieu d u n g qua mach c6 gia t r i bang Cdch 1: Z c i K h i mach xay cgng h u d n g t h i d u n g k h a n g ciia t u b a n g A 250Q •^co ,0, _Zci+Zr B Q •I; C l O o V S Q Huang dan Chon D , j de d u n g k h a n g ciia tu la Zc T u gia trj do, ne'u tang d u n g k h a n g t h e m 20 ^ hoac g i a m d u n g k h a n g d i 10 Q t h i cong suat tieu t h u tren d o a n mach la nhu n h a u H o i t u Zc, phai thay d o i d u n " ' 'unng cua t u n h u t h e n a o de cong suat tieu t h u tren mach I o n nhat? CoCn =^ Z L • = 2Z •CI =^ ^ l i ^ C 50/71 nF ,^ D 150/n ^F dan (Pi = + a (P2 = - a = 1,5Za _ Z L - Z a _ • ' ''C^ = 200 ( Q ) coCj • < Zc2 = Pl = P2 ^ Z l = Z2 D 200 Q V i d u : Cho d o a n mach R L C no'i tiep v o i C thay d o i d u g c Ban d a u d i e u chinh 179 ,,; B 100/V3 , Huong &fi ! i i fiJ' (Pl = + a > Zi=Z2 , => R = lOO(Q) => Chon B Pj = P2 TzV ifd si/y ra: Z ^ Q = > Chon A • " d u n g C d e n gia t r i lO-VCn) F hoac 10 •'/(37i) F t h i cong suat tieu t h u tren doan j^j^i ^g^^ hllVng (Lmx, Ucmnx, UKimx, Pimx) thl Zco ^ Z L Z L = ^ C l + ^C2 _ CO d o t u cam L va tu d i e n c6 dien d u n g C thay d o i d u g c D i e u c h i n h d i e n ; u CM y: Khi C thay doi hai gia tri Ci va C2 c6 ciing I, Ui., UR, P thi 2J vao hai d a u doan mach mac n o i tiep g o m dien t r o t h u a n R, cuon cam thuan I' 7C 1) mach d e u c6 gia t r i bang n h u n g pha ban d a u ciia d o n g d i e n h o n kem Co cung P=>Zi=Z2 U^Rt Q = rRt =R2+(ZL-Zcif (Zc+20) + (Zc-10) yfi d u 5: Dat d i e n ap xoay chieu c6 gia trj hieu d u n g k h o n g d o i , tan so' 50 H z I/TI ( H ) ^^^^ dan Z^^H-Zr Zco - vifn I Theo bai ra: 2a = 7t/2 => a = n/A => tancpi = R 0,5Zci = - l = > Z c i =200(Q)=>Ci = 100 (OZ^I > Chon C Cdch 2: Z = ^ C + Z c = tana 50 - — " ^ (F) 7t ) n tan q,, = Z, tancpi =• ^ ^ R = - ^ Z c = 200(Q) ^ C, = 100 wZ^i = ^ l O ^ ^ (F) 71 [ } , cugn , u = 23,4.3x/3cos 1207it , cam thuan va tu dien c6 d u n g khang Zc thay d o i K h i Zc = Zci =100 Q hone ,, k h i Zc = Zc2 = 300 Q thi cong suat tieu thu ci'ia doan mach nhir Ne'u • c u o n g d o n g dien qua mach k h i Zc = Zci la ii = V2 cos(110Ft + K/12) (A) • t h l k h i Z G = Zc2 d o n g dien qua mach c6 bieu thiic • A i2 = \/2 cos(l lOnt + STT/I2) ( A ) C i2 = 2cos(1107it + 57r/12) (A) Huong Pi = P2 ^ Z , = Z2 ^ Z L = I = — , '2 scim pha h d n i j la ^ ^cj,., , QJJv ' A , • , ' ^ ' Qj^f,: (^Q, CMy: M't:- - ni;):=' .-'j-i ^;- -'- •••3::^ J - \!; coC = 200Q- * , '; '\ , (V)nKlu((inK '•' ->Z, = Z r _ =200=>i = - = l,lcos 1207tt (A) R U, thi a'la chiing D\ta vao thi ta sc thay: Zc chng gan Zco thi I, P, UR, UI cang Ian, ciuig xa thi cnng he (Z^o ' Zn+Zr, * L = /2 = / f / n Z c o " = Z L = ^ ^ ^ " = Z, ); [Zc3 e ( Z c i ; Z c ) = ^ l > I -C3 Zci;Zc2 • u• Khi C ilmy doi dcso smili cac gin tri I, P, UR, UI C6 tlwdung theoZc ^•' f l i^ = 6cos(1207it + 71/6) ( A ) , „ Giira A B co mot dien ap xoay chieu luon on d i n h u = (200i) = 2 Z - = 220cos 1207rt + - i ( V ) =?ChonB D i^ = ^3 cos(1207tt + 7./12) ( A ) = 70,2^3 cos 1207tt + - ( V ) ; D ui = 110 V cos(1207rt + 7r/2) (V) ,^,.p.^ Liic nay, d o n g dien qua mach C O bieu thiic ,_ B ui = 220cos(1207tt + 71/6) (V) Zr = 571/12) ( A ) K h i C = C thi he so cong sua't cua doan mach c6 gia t r i Ion nha't Huong 12 C U I , = 220cos(1207rt + 7i/2) (V) / 71 n h a u Biet c u o n g d o d o n g dien qua mach k h i C = Ci la i i = - i< _7I^ A ui = 264cos(1207tt + 7t/6) (V) ^-^'^ hoac k h i C = C2 = l/(46 807i) F t h i cong suat tieu thu cua doan mach n h u ;v-, V i du 9: Cho doan mach dien xoay chieu A B k h o n g phan n h a n h g o m m o t cuon ; cuon cam thuan va tu dien ccS dien d u n g C thay d o i K h i C = Ci = l/(74 887i) F • ChonA ^ •'^'^ ^ A b = 3^cosl207ct hdn D i2 = V2 cos(l lOTit - T./4) ( A ) 71 , , , n ^ = = > ( p , = — => u sdm pha h d n i j l a — R V3 6 Zi — Zfo 71 • ^ , , 1V ^3 pha d o n g 100 il = 200(Q) — = - —!=•=> i i s6m cam thuan, mot t i i dien ccS dien d u n g C thay doi dugc, m o t di§n t r o hoat ZL - Z r i ^ = B i2 = 2cos(l Orct - 7r/4) ( A ) tanq)i=— tan(p2 = — > V3 Z , = R + ( Z L - Z o f =23,4Q ' V i du 7: Cho doan mach dien xoay chieu RLC no'i tie'p g o m R = 100 - Z•CI R -.Sc.o Hu&ugdan ^C34^ci;zc2] i^^j" Chon B.' V Deso siinh P^ im Pi ta c6 tlwdiing phiivng phnp "giiuig day" nhu saii: Tir P.; I I3 > I2 => Chon C A.250^'+(Z,,-Zef ' U.,='Z|.=' ^Ze.-2Z,Z,+(R^+Z?.) , |(R2+Z^.) V-2ZC^^ sn'*4 i A i - y u t i,i.U(.' 4^ ii/^, l / Z i theo kieu ham tam thuc bac nen: U L phu thuoc +I' ^ ' ^ = ——* y • R + Z(- -11) Uc = lZc = UZc VR^.(Z,-Zer u , An- R ' + COL- ^ wC, wC U,, = 1.ZL = u R^ + (oL - r.(0L = L W - 1 N/RM^T^ phu thucK J(R^.Z^).|T2.ZC.^.T = -^Li—5L2 Ln - ^tlll2_ " L1+L2 2 , -72 • R' +Z UL=I.ZL= ^ ^ ^ 2", cV+1 ,2 = —-— , U i phu L_R_^_ C ,, ^ thuoc 1/(0^ theo kieu ham tam thuc bac nen: — = = :>• , ^ 1 CO? (0, n V i du 1: Cho mach dien xoay chieu noi tiep gom cugin day thuan cam c6 tM cam L thay doi duoc, tu dien c6 dicM-i dung C va dien tro R, Co hai gia UL phu + =— — ^ = ^ ^ ^ ZLO R^+z^ , = -(100-^ + 300"' ] => R = 5072 (f^) ^ Chon C R2+502 2^ ^ V / Vi du 3: (DH-2009) Dat dien ap xoay chieu u = Uocoscot c6 Uo khong doi va co thay doi dugc vao hai dau doan mach c6 R, L, C mac no'i tiep Thay doi (o thi cuong dong dien hieu dung mach co = coi bang cuong dong dien hieu dung mach co = C02 He thiic dung la : A (COI+co2)LC = B coia)2LC = l C (coi + co2)2LC = D (coi+(02)2LC = l Huang dan • It , (R^.Z^).J^-2.Zc.-l.l thuoc 1/ZL theo kieu ham tam thuc bac nen: ^\ 0^2 -2 - ' , U c phu ,C~ ' U L p h y thuoc =>ChonA V i?;; : v ' -'^ ) , - • ; ; ' i ^ -^'-r,: ^ ;,!,,.! „';,-, Vi du 2: Mach dien xoay chieu RLC khong phan nhanh, dung khang bang 50Q, dien tro thuan R va cuon cam thuan c6 cam khang ZL thay doi Nguai ta nhan thay ZL C6 gia tri ung vai 100 Q va 300 Q thi dien ap hi§u dung tren cuc)n cam c6 cung mc)t gia trj Tinh R A 25 Q B 19 Q C 50 V2 Q D 50 Q, Vo •,hm ) Huaitgdan ,.!) t-,, j n ? « ''.u ' 1/Zi theo kieu ham tam thuc bac nen: — u 7R^+(Z, -Ze)^ C.L = L i L / ( L i + L ) , I phu thuoc Zc theo — UZ, 'iA;,'.! Vl^t A L = (Li + L2)»'\ L = a5(Li + L2) U L = I-ZL = , , kieu ham tam thuc bac nen: Z^^„ = — * M T V If V V H Khang khac cua L la L i va L2 thi dien ap hieu dung tren cuon ram c6 cung mot gia trj Gia tri cua L de dien ap hieu dung tren cuon cam cue dai la U Z ^ VTV2 t^p - Chu Cdch 1: I = — = z Wo r nen: COQ = , ^ R2 + c o L rr^ ^C0jC02 = / — - LC »- , , I phu thuoc co theo kieu ham phan thuc ^ coC, y • • • hi'!:- Afi frv; y CO1CO2LC = => Chon B ' v 179