D. cuon thuan cam va dien tro thuan, voi Rx = R va Zịx = 2ZL. ' ' •? X ' Vi U 2 = 2ui nen dien ap tren cuon day va tren hop kin phai cung phạ Do do, Vi U 2 = 2ui nen dien ap tren cuon day va tren hop kin phai cung phạ Do do, X phai chiia R L sao cho Rx = 2R va Zịx = 2Zi :=> Chon C , ,
Chuy: ^ . , i = I„ coswt ,; " 2 / '•..'.ríi-/ " L r = Uoi COS(o-'t + 9|,r ) ; t ' T l 9|.r = • ^ ^ W u - 1) •3- X~l—ffl ^ ' - Q < "
ux = U|)2 cos (tot + 9x ) V ? ' ,j ' t ' /
Ncu ux diit cue dni tiv lion uir vc tliai ^lan In Tin (tírc In vépha la iTtIn) tin
2 T t f t , :„l, i s , ! i; !• -i ,; ; i, i I, .i (. l
= 9|.r
n 1) i / t 1 • i i , I I 1
= In C O S u j t
2) u = U„, cos(wt + 9KC ) ; 9KC = - j ^ • 4>_fA-| [.
U x = U„2 cos(wt + >px)
X
Neil ux dat CUT dai som lion URC vcthai gian la 'Tin (tuc la vepha la iTiln) thl
Vi du 7: Mot doan mach xoay chieu gom cuon day c6 dien tro 100 Q, c6 cam khang 100 N/S Q noi tiép voi hop kin X. Tai thai diem ti dien ap tírc thai tren
cuon day cue dai den thoi diem t2 = ti + T/4 (vai T la chu ki dong dien) dien
ap tuc thoi tren hop kin cue daị Hop kin X c6 the la
Ạ cuon cam CO dien tro thuan.
B. tu dien noi tiép vdi dien tro thuan.
C. cuon cam thuan. i j uj_^, ,)U ^) [ ^y, 1/
D. cuon cam thuan nói tiép voi tu dien. . -
, , , , , , , , ; i „ , Humgdan
7, r- IT , • . , . •
Vi ux dat cue dai t r i hon ui.r ve thai gian la T/4 (tuc la ve pha la 27i/2) nen:
2 6
Ta tháy: --^ < 9x <^ ri^n X c6 the la dien tro mac noi tiép voi tu => Chon B.
18
, 8: Mot doan mach xoay chieu gom cuon day c6 di^n tro 100 Q, c6 cam ^* kha"S ^ *^^P '^^P ^^'^ ^' ^P ^"^'^ ^'^"^^ ^"^^"^
cUon day cue dai den thoi diem t2 = ti + 3T/8 (vai T la chu ki dong dien) dien
tiíC thoi tren hpp kin eye daị Hpp kin X c6 the la
^ cupn cam c6 di^n tro thuan. B. tu dien noi tiép voi dien tro thuan.
C tu dien. D. cuon cam thuan.
--•X't"- '^4 i Huong dan "cd = Uoi cos tanked Ux = U02 cos T f2-Kt •9x i = IQ cos 2-Kt T , (adsbygoogle = window.adsbygoogle || []).push({});
Ucd sam pha hon ux ve thai gian la 3T/8 va ve pha la — . 2-K 3T
=^u)v= — - — = - — CO the la tu dien Chon C. '
^^'^ 4 4 2
Vi du 9: Dat dien ap xoay chieu u = 200 %/2 coslOOTit (V) vao hai dau doan mach AB gom doan A M noi tiép voi doan MB thi cuong do hieu dung qua mach
la 3 (A). Dien ap tuc thoi tren A M va MB lech pha nhau 7i/2. Doan mach A M
gom cuon cam thuan c6 cam khang 20N/3 Q noi tiép voi dien tro thuan 20 Q va doan mach MB la hop kin X. Doan mach X chiia hai trong ba phan tu hoac dien tro thuan Ro hoac cuon cam thuan c6 cam khang ZLO hoac tu dien
CO dung khang Zco mac nói tiép. Hop X chua
Ạ Ro = 93,8 Q va Zco = 54,2 Q. , B. Ro = 46,2 Q va Zco = 26,7 Q.
C. ZLO = 120 Q va Zco = 54,2 Q . C. ZLO = 120 Q va Zco = 120 Q .
Huong dan 3^ 4 • 'liiii * 1 1 = 60" U , j = I . Z , d = I J R 2 + Z ^ - 3 J 2 0 2 + ( 2 0 V 3 ) = 1 2 0 ( V ) A A M B uuong tai M =^ M B = V A B ^ - A M ^ = 7 2 0 0 ^ - 1 2 0 ^ = 160(V)
A M E B vuong tai E=>ix = ip^-j = 6 0 " URO = 160 sin cv = 80V3 RQ = =-160 cos a = 80 Zco ~ I Uco I « 4 6 , 2 ( n ) ;26,7(Q) =^ Chon B. f
U p A . ^ ^ M X . B A M u , R O = 60* u , .^•(ttU'jIÍf'rHiO i\\ U CO: • E B
V i du 10: M o t cuon day c6 dien tro thuan R = 100 N/S Q va do t u cam L = 3/^
(H). Mac noi tiep voi cuon day mot doan mach X c6 tong tro Zx roi mac vao 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 thi thay dong dien qua mach nhanh pha 30" so voi hieu dien the hai dau doan mach X va c6 gia trj hieụdung 0,3 Ạ Cong suat tieu thy tren doan
mach X la bao nhieủ „ j . .
Ạ 3 0 W . • , B . 2 7 W . C. 9 V 3 W . Huang dan • - • Huang dan • - • •At :r D. 18x/3 W . Z,rf = + Zl = 200^/3 (n) = ^ U , ^ = I Z c d = 6 0 7 3( V ) tanked = - r = ^ R M X M Ve gian do vec to cho doan A M truoc, roi ve
tiep doan M B tre pha hon dong dien la 30". Ta nhan thay A A M B vuong tai M nen:
6 0 V 3 /
A" 120 V
Ux = M B = ^120^ - (60>y3)' = 60(V)
Px = U x l c o s i p , = 60.0,3.cos30" = 9^/3(W) =^ Chon C.
Binh luan: Sau khi fun dime MB sc tun dime ;^6c a roi gdc (p va P = UJcoscp.
V i du 11: Cuon day c6 dien tro thuan R va do t u cam L mac vao dien ap xoay chieu u =
250N/2 coslOOTct (V) thi dong dien qua cuon day
CO gia t r i hieu d u n g la 5 A va lech pha so voi
dien ap hai dau doan mach la 7t/6. Mac noi tiep
cuon day voi doan mach X thi cuong do hieu
d u n g qua mach la 3 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. ^ ':30^^'""
A*
M (adsbygoogle = window.adsbygoogle || []).push({});
30'
M
> B
Cong suat tieu thu tren doan mach X la Ạ 200W. . B. 3 0 0 W .