KHÓ 1

["TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 \uf0e6 \uf077 \uf0f62 \uf02d 2n \uf02d1 \uf0e6 \uf077 \uf0f62 \uf02b \uf0e6\uf0e8\uf0e71 \uf02d 1 \uf0f6 \uf03d 0 \uf0be\uf077\uf0be\uf03d3\uf077\uf0bek1\uf03d\uf03d2\uf0be32\uf0770\uf0be\uf0ae n \uf02d1 \uf03d 7 \uf0e7 \uf0770 \uf0f7 \uf0e7 \uf0770 \uf0f7 k2 \uf0f8\uf0f7 8 \uf0e8 \uf0f8 \uf0e8 \uf0f8 \uf0de UL max \uf03d U \uf03d 206,56\uf028V\uf029 \uf0de Ch\u1ecdn C. 1 \uf02d n\uf02d2 C\u00e2u 151. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d 120 2 cos 2\uf070ft (V) (f thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi f = f1 ho\u1eb7c f = f1 + \u0394f1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng \u1edf hai \u0111\u1ea7u t\u1ee5 \u0111i\u1ec7n c\u00f3 c\u00f9ng gi\u00e1 tr\u1ecb 125V. Khi f = f2 ho\u1eb7c f = f2 + \u0394f2 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng \u1edf hai \u0111\u1ea7u cu\u1ed9n c\u1ea3m c\u00f3 c\u00f9ng gi\u00e1 tr\u1ecb 125V. T\u1ec9 s\u1ed1 \u0394f1\/ \u0394f2 g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 1,6. B. 1,5. C. 0,65. D. 0,58. H\u01b0\u1edbng d\u1eabn C\u00e1ch 1: * S\u1eed d\u1ee5ng k\u1ebft qu\u1ea3 c\u00f9ng Ph\u00f9ng L\u00e3o: 1 \uf02d k\uf02d2 \uf03d \uf0771 \uf03d \uf0771' \uf03d \uf0771 \uf02d \uf0771' \uf03d \uf044f1 \uf0bek\uf0be\uf03d1,\uf0be25\uf0ae \uf044f1 \uf03d 0, 6 \uf0de Ch\u1ecdn D. \uf0772 \uf077'2 \uf0772 \uf02d \uf077'2 \uf044f2 \uf044f2 C\u00e1ch 2: U1 U \uf03d 1, 25U \uf077C \uf03d * T\u1eeb UC \uf03d IZC \uf03d \uf0f62 R2C \uf0f6 1 \uf0f8\uf0f7 \uf0e7\uf0e61 \uf02d \uf0452\uf045L\uf045\uf045\uf0f7\uf0f8 R 2 \uf02b \uf0e6 \uf077L \uf02d \uf077C L2C2\uf0774 \uf02d 2 \uf0e8\uf045 \uf045\uf045 LC\uf0772 \uf02b1 \uf0e8\uf0e7 n \uf02d1 \uf0de \uf0e6 \uf077 \uf0f62 \uf02d 2n\uf02d1 \uf0e6\uf077 \uf0f62 \uf02b 0,36 \uf03d 0 \uf0de \uf0ec\uf0ef\uf0e7\uf0e6 \uf0771 \uf0f62 \uf03d n \uf02d1 \uf02b n\uf02d2 \uf02d 0, 36 \uf0e7 \uf0770 \uf0f7 \uf0e7 \uf0f7 \uf0ef\uf0e8 \uf0770 \uf0f7 \uf03d n \uf02d1 \uf02d n\uf02d2 \uf02d 0, 36 \uf0e8 \uf0f8 \uf0e8 \uf0770 \uf0f8 \uf0ed \uf0f8 \uf0ef\uf0e6 \uf0771' \uf0f62 \uf0ef\uf0e7 \uf0770 \uf0f7 \uf0ee\uf0e8 \uf0f8 * T\u1eeb UL \uf03d IZL \uf03d U\uf077L \uf03d U \uf03d 1, 25U R 2 \uf02b \uf0e6 \uf077L \uf02d 1 \uf0f62 1 1 \uf02d 2\uf0e6\uf0e71\uf02d R2C \uf0f6 1 1 \uf02b1 \uf0e8\uf0e7 \uf077C \uf0f8\uf0f7 L2 C2 \uf0774 \uf0e8 \uf0f7 \uf0772 2L \uf0f8 LC \uf0e6 \uf0f62 \uf0e6 \uf0f62 \uf0ec\uf0ef\uf0e7\uf0e6 \uf0772 \uf0f62 \uf03d n\uf02d1 \uf02b n\uf02d2 \uf02d 0, 36 \uf03d 1 \uf0e6 \uf0771 \uf0f62 \uf0e7 \uf0f7 \uf0e7 \uf0f7 \uf0ef\uf0e8 \uf0770 \uf0f7 \uf03d n\uf02d1 \uf02d 0, 36 0, 36 \uf0e7 \uf0770 \uf0f7 \uf0de 0, 36 \uf077 \uf0f8 \uf02d 2n \uf02d1 \uf0e8 \uf077 \uf0f8 \uf02b1 \uf03d 0 \uf0de \uf0ed \uf0f8 \uf0e8 \uf0f8 \uf0770 \uf0770 \uf0ef\uf0e6 \uf077'2 \uf0f62 n\uf02d2 \uf02d 0, 36 \uf0e8 \uf0ef\uf0e7 \uf0770 \uf0f7 0, 36 \uf03d 1 \uf0e6 \uf0771' \uf0f62 \uf0ee\uf0e8 \uf0f8 0, 36 \uf0e7 \uf0770 \uf0f7 \uf0e8 \uf0f8 \uf0de \uf0772 \uf02d \uf077'2 \uf03d 1 \uf0771 \uf02d \uf0771' \uf0de \uf044f1 \uf03d 0, 6 \uf0770 0, 6 \uf0770 \uf044f2 \uf0de Ch\u1ecdn D. C\u00e2u 152. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U kh\u00f4ng \u0111\u1ed5i, \u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai U(V) \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch m\u1eafc 100 n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n 80 tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. H\u00ecnh v\u1ebd l\u00e0 \u0111\u1ed3 th\u1ecb ph\u1ee5 thu\u1ed9c C\u1eeb c\u1ee7a \u0111i\u1ec7n \u00e1p hi\u1ec7u 160 UL 140 UC d\u1ee5ng tr\u00ean L v\u00e0 \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean C. T\u1ec9 s\u1ed1 \uf044\uf0771 \/ \uf044\uf0772 g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau 120 \u0111\u00e2y? 100 80 A. 0,519. B. 0,513. 60 40 C. 0,517 D. 0, 515 20 0 \uf044\uf0772 \uf077\uf028rad \/ s\uf029 \uf044\uf0771 H\u01b0\u1edbng d\u1eabn * S\u1eed d\u1ee5ng k\u1ebft qu\u1ea3 c\u1ee7a Ph\u00f9ng L\u00e3o: 1 \uf02d k\uf02d2 \uf03d \uf0771 \uf03d \uf0771' \uf03d \uf0771 \uf02d \uf0771' \uf03d \uf044\uf0771 \uf0bek\uf0be\uf03d14\uf0be0\/12\uf0be0\uf0ae \uf044\uf0771 \uf03d 13 \uf03d 0, 515 \uf0772 \uf077'2 \uf0772 \uf02d \uf0772' \uf044\uf0772 \uf044\uf0772 7 \uf0de Ch\u1ecdn D.","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 C\u00e2u 153. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d 150 2 cos \uf077t (V) (\u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch m\u1eafc U(V) U1 n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. H\u00ecnh v\u1ebd l\u00e0 \u0111\u1ed3 th\u1ecb ph\u1ee5 thu\u1ed9c \u03c9 c\u1ee7a \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L v\u00e0 \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean C. Gi\u00e1 tr\u1ecb U1 g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 270 V. B. 180 V. UL C. 200V. D. 250 V. 0 UC 3\uf077 5\uf077 \uf077\uf028rad \/ s\uf029 H\u01b0\u1edbng d\u1eabn * S\u1eed d\u1ee5ng k\u1ebft qu\u1ea3 c\u1ee7a Ph\u00f9ng L\u00e3o: \uf0ec \uf0771' \uf03d \uf0771 \uf03d1 \uf02d k \uf02d2 \uf0ef\uf0ef \uf077'2 \uf0772 \uf0771\uf077'2 \uf03d \uf0ed 1 \uf0ef\uf0ef\uf0ee\uf0771 \uf0772 \uf03d LC ' \uf0be\uf0be\uf0be\uf0be\uf0be\uf0be\uf0ae\uf0771 \uf03d\uf077'2 \uf03d\uf077R \uf03d1 \uf0ef\uf0ef\uf0ed\uf0ee\uf0ec\uf077k 1\uf03d\uf03d0\uf077, 5R \uf03d 15\uf077 \uf0de Ch\u1ecdn D. LC 10 \uf0de U1 10 \uf0771' \uf03d3\uf0771 ;\uf0772 \uf03d5\uf077 \uf03d kU \uf03d 75 \u0110\u1ed8 L\u1ec6CH PHA C\u1ef0C \u0110\u1ea0I C\u1ef0C TI\u1ec2U C\u00e2u 154. \u0110oan m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo \u0111\u00fang th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf R1, \u0111i\u1ec7n tr\u1edf R2 v\u00e0 cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. N\u1ebfu \u0111\u1eb7t v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB hi\u1ec7u \u0111i\u1ec7n th\u1ebf kh\u00f4ng \u0111\u1ed5i 18 V th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua m\u1ea1ch l\u00e0 20 3 mA v\u00e0 hi\u1ec7u \u0111i\u1ec7n th\u1ebf tr\u00ean R1 l\u00e0 12 V. N\u1ebfu \u0111\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos100\uf070t (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB \u0111i\u1ec1u ch\u1ec9nh L \u0111\u1ec3 \u0111\u1ed9 l\u1ec7ch pha gi\u1eefa \u0111i\u1ec7n \u00e1p tr\u00ean \u0111o\u1ea1n R2L v\u00e0 u l\u00e0 c\u1ef1c \u0111\u1ea1i. Khi \u0111\u00f3 L b\u1eb1ng A. 1\/\u03c0 H. B. 2\/\u03c0 H. C. 3\/\u03c0 H. D. 4\/\u03c0 H. H\u01b0\u1edbng d\u1eabn \uf0ef\uf0ef\uf0ecR1 \uf03d UR1 \uf03d 200 3\uf028\uf057\uf029 I 3 \uf028\uf057\uf029 * Ngu\u1ed3n 1 chi\u1ec1u: \uf0ed \uf0ee\uf0ef\uf0efR 2 UR2 \uf03d I \uf03d 100 * Ngu\u1ed3n xoay chi\u1ec1u: ZL \uf02d ZL R1 R1 R2 \uf028 \uf029tan \uf061 \uf03d tan \uf03d R1 \uf02b R2 \uf03d \uf028R1 \uf02b R2 \uf029 R2 \uf0a3 \uf028R1 \uf02b R2 \uf029R2 \uf06aR2L \uf02d \uf06a ZL 1\uf02b ZL 1 ZL 1 R2 R1 \uf02b R2 \uf045Z\uf045L \uf045\uf02b\uf045 \uf045\uf028 R\uf045\uf0451 1 \uf045\uf02b\uf045R\uf0452\uf045\uf029\uf045R\uf045\uf0452 \uf028R1 \uf02b R2 \uf029R2 \uf0b32 1 \uf028R1 \uf02b R2 \uf029R2 \uf0de tan \uf061max \uf0db ZL \uf03d R2 \uf028R1 \uf02b R2\uf029 \uf03d 300 \uf028\uf057\uf029 \uf0de L \uf03d 3 \uf028H\uf029 \uf0de Ch\u1ecdn C. \uf070 C\u00e2u 155. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U, \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB n\u1ed1i ti\u1ebfp g\u1ed3m \u0111o\u1ea1n AM ch\u1ee9a bi\u1ebfn tr\u1edf R (t\u1eeb 0 \u0111\u1ebfn r\u1ea5t l\u1edbn), \u0111o\u1ea1n MB ch\u1ee9a t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c v\u00e0 \u0111i\u1ec7n tr\u1edf thu\u1ea7n R0 m\u1eafc n\u1ed1i ti\u1ebfp sao cho \uf0772LC \uf03e 1 . C\u1ed1 \u0111\u1ecbnh C = C0 v\u00e0 L = L0 thay \u0111\u1ed5i R \u0111\u1ebfn c\u00e1c gi\u00e1 tr\u1ecb R1 v\u00e0 R1 + 65 \u03a9 th\u00ec l\u1ea7n l\u01b0\u1ee3t c\u00f4ng su\u1ea5t ti\u00eau th\u1ee5 tr\u00ean \u0111o\u1ea1n AB c\u1ef1c \u0111\u1ea1i (gi\u00e1 tr\u1ecb \u0111\u00f3 l\u00e0 Pmax) v\u00e0 tr\u00ean \u0111o\u1ea1n AM c\u1ef1c \u0111\u1ea1i (gi\u00e1 tr\u1ecb \u0111\u00f3 l\u00e0 PR max \uf0a3 Pmax \/ 3 ). C\u1ed1 \u0111\u1ecbnh R = R1 + 65 \u03a9 thay \u0111\u1ed5i c\u1ea3 L v\u00e0 C \u0111\u1ec3 cho \u0111\u1ed9 l\u1edbn \u0111\u1ed9 l\u1ec7ch pha gi\u1eefa uMB v\u00e0 uAB c\u1ef1c \u0111\u1ea1i, khi \u0111\u00f3 L \uf03d 31, 5L0 v\u00e0 C \uf03d C0 \/ 31, 5 . Gi\u00e1 tr\u1ecb R0 l\u00e0 A. 63 \u03a9. B. 16 \u03a9. C. 65\/6 \u03a9. D. 37 \u03a9. H\u01b0\u1edbng d\u1eabn \uf0ec\uf0efPmax \uf03d U2 \uf0ef 2ZL0C0 \uf028 \uf029* N\u1ebfu R0 \uf03c ZL0C0 th\u00ec \uf0ed \uf0be\uf0be\uf0be\uf0be\uf0be\uf0aePRmax \uf03cPmax \/3 \uf0ef\uf0ee\uf0efPR max U2 \uf03d 2 R 2 \uf02b Z2 \uf02b R0 0 L0C0 R 2 \uf02b Z2 \uf02b R0 \uf0b3 3ZL0C0 \uf0de R0 \uf0b3 4 ZL0C0 \uf0de V\u00f4 l\u00fd \uf0de R0 \uf03e ZL0C0 n\u00ean Pmax khi R \uf03d R1 \uf03d 0 0 R 0C0 3","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 2 Z2 0 L0C0 \uf028 \uf029Khi PR max th\u00ec 65 \uf03d R \uf02b 1 * C\u1ed1 \u0111\u1ecbnh R \uf03d R1 \uf02b 65 \uf03d 65\uf057 thay \u0111\u1ed5i c\u1ea3 L v\u00e0 C: ZL \uf02d ZC \uf02d ZL \uf02d ZC 65 65 R0 tan \uf028 \uf06aMB \uf02d \uf06aAB \uf029 \uf03d 65 \uf02b R 0 \uf03d \uf0a3 R0 \uf02865 \uf02b R0 \uf029 ZL \uf02d ZC . ZL \uf02d ZC R0 \uf02865 \uf02b R 0 \uf029 2 1\uf02b R0 65 \uf02b R 0 \uf028ZL \uf02d ZC \uf029 \uf02b \uf028 ZL \uf02d ZC \uf029 D\u1ea5u b\u1eb1ng khi ZL \uf02d ZC \uf03d R0 \uf02865 \uf02b R 0 \uf029 \uf0db ZL0C0 \uf03d R 0 \uf028 65 \uf02b R 0 \uf029 \uf028 2 \uf029 31, 5 * Thay (2) v\u00e0o (1): 652 \uf03d R 2 \uf02b R 0 \uf02865 \uf02b R 0 \uf029 \uf0de R0 \uf03d 63\uf028\uf057\uf029 \uf0de Ch\u1ecdn A. 0 31, 5 C\u00e2u 156. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p U = U0cos\u03c9t (V) (U0, \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf R1, \u0111i\u1ec7n tr\u1edf R2 = 0,5R1, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi L = L1 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean R2L l\u1ec7ch pha c\u1ef1c \u0111\u1ea1i so v\u1edbi u, khi \u0111\u00f3 h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t m\u1ea1ch AB l\u00e0 3 \/ 2 . Khi L = L2 th\u00ec c\u01b0\u1eddng \u0111\u1ed9 hi\u1ec7u d\u1ee5ng trong m\u1ea1ch c\u1ef1c \u0111\u1ea1i. T\u1ef7 s\u1ed1 L1\/L2 b\u1eb1ng A. 4. B. 2. C. 0,25. D. 0,5. H\u01b0\u1edbng d\u1eabn * Chu\u1ea9n h\u00f3a: R 2 \uf03d 1 \uf0de R1 \uf03d 2 tan \uf06aR2L \uf02d tan \uf06a 2ZL \uf02b ZC 1 \uf02b tan \uf06aR2L tan \uf06a ZL ZL \uf02d ZC \uf028 \uf029 \uf028 \uf029* T\u1eeb y \uf03d tan \uf06aR2L \uf02d \uf06a \uf03d \uf03d 3 \uf02b \uf0bex\uf0be\uf03d2Z\uf0beL \uf02b\uf0beZC \uf0ae y \uf03d 4 12 1 \uf0a34 1 \uf0de ymax \uf0db x2 \uf03d 12 \uf02b 3ZC2 \uf02b 3ZC2 2 12 \uf02b 3ZC2 \uf02d 4ZC \uf045 \uf045\uf045x\uf045\uf045\uf045 \uf0b32 12\uf02b3ZC2 \uf028 \uf029\uf0db 3Z2L \uf02d 2 \uf03d 6 \uf0be\uf0be43 \uf03dco\uf0bes2 \uf06a\uf0be\uf03d 32\uf0be\uf02b\uf028Z3\uf0beL2\uf02dZ\uf0beC \uf0292\uf0be\uf0ae \uf0ec\uf0ef\uf0edZL \uf03d 3 ZL \uf02d ZC \uf0ef\uf0eeZC \uf03d 2 3 * Khi m\u1ea1ch c\u1ed9ng h\u01b0\u1edfng th\u00ec: ZL2 \uf03d ZC \uf0de L1 \uf03d ZL1 \uf03d 2 3 \uf03d 0,5 \uf0de Ch\u1ecdn D. L2 ZL2 3 C\u00e2u 157. \u0110\u0103t \u0111i\u1ec7n \u00e1p U = U0cos\u03c9t (V) (U0, \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf R1, \u0111i\u1ec7n tr\u1edf R2 = 0,5R1, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi L = L1 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean R2L l\u1ec7ch pha c\u1ef1c \u0111\u1ea1i so v\u1edbi u, khi \u0111\u00f3 h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t m\u1ea1ch AB l\u00e0 3 \/ 2 . Khi L = L2 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L c\u1ef1c \u0111\u1ea1i. T\u1ef7 s\u1ed1 L1\/L2 b\u1eb1ng A. 7\/2. B. 2. C. 2\/7. D. 0,5. H\u01b0\u1edbng d\u1eabn * Chu\u1ea9n h\u00f3a: R 2 \uf03d 1 \uf0de R1 \uf03d 2 tan \uf06aR2L \uf02d tan \uf06a 2ZL \uf02b ZC 1 \uf02b tan \uf06aR2L tan \uf06a ZL ZL \uf02d ZC \uf028 \uf029 \uf028 \uf029* T\u1eeb y \uf03d tan \uf06aR2L \uf02d \uf06a \uf03d \uf03d 3 \uf02b \uf0bex\uf0be\uf03d2Z\uf0beL \uf02b\uf0beZC \uf0ae y \uf03d 4 12 1 \uf0a34 1 \uf0de ymax \uf0db x2 \uf03d 12 \uf02b 3ZC2 \uf02b 3ZC2 2 12 \uf02b 3Z2C \uf02d 4ZC \uf045 \uf045\uf045x\uf045\uf045\uf045 \uf0b32 12\uf02b3ZC2 \uf028 \uf029\uf0db 3ZL2 \uf02d 2 \uf03d 6 \uf0be\uf0be34 \uf03dco\uf0bes2 \uf06a\uf0be\uf03d 32\uf0be\uf02b\uf028Z3\uf0beL2\uf02dZ\uf0beC \uf0292\uf0be\uf0ae \uf0ed\uf0ec\uf0efZL \uf03d 3 ZL \uf02d ZC \uf0ef\uf0eeZC \uf03d 2 3 R1 \uf02b R 2 2 \uf02b ZC2 ZC * Khi \uf028 \uf029UL max : ZL2 \uf03d \uf03d 3,5 3 \uf0de L1 \uf03d ZL1 \uf03d 3 \uf03d 1 L2 ZL2 3, 5 3 3, 5 \uf0de Ch\u1ecdn C. C\u00e2u 158. \u0110\u0103t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u \uf03d 220 2 cos100\uf070t (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB theo th\u1ee9 t\u1ef1 g\u1ed3m 3 \u0111o\u1ea1n n\u1ed1i ti\u1ebfp nhau: \u0111o\u1ea1n AM c\u00f3 \u0111i\u1ec7n tr\u1edf thu\u1ea7n R1, \u0111o\u1ea1n MN ch\u1ee9a t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c n\u1ed1i ti\u1ebfp v\u1edbi m\u1ed9t \u0111i\u1ec7n tr\u1edf thu\u1ea7n R2, \u0111o\u1ea1n m\u1ea1ch NB ch\u1ee9a cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. \u0110i\u1ec1u ch\u1ec9nh L v\u00e0 C \u0111\u1ec3 c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n t\u1ee9c th\u1eddi trong m\u1ea1ch i lu\u00f4n c\u00f9ng pha v\u1edbi \u0111i\u1ec7n \u00e1p t\u1ee9c th\u1eddi hai \u0111\u1ea7u m\u1ea1ch; \u0111\u1ed3ng th\u1eddi \u0111i\u1ec7n \u00e1p UMN tr\u1ec5 pha so v\u1edbi \u0111i\u1ec7n \u00e1p uAN m\u1ed9t g\u00f3c l\u1edbn nh\u1ea5t l\u00e0 36,87\u00b0. Khi \u0111\u00f3, \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch MN c\u00f3 gi\u00e1 tr\u1ecb l\u00e0 A. 123 (V). B. 173 (V). C. 141 (V). D. 156 (V). H\u01b0\u1edbng d\u1eabn * M\u1ea1ch c\u00f4ng h\u01b0\u1edfng n\u00ean ZL \uf03d ZC .","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 * T\u1eeb tan \uf028\uf06aAN \uf02d \uf06aMN \uf029 \uf03d tan \uf06aAN \uf02d tan \uf06aMN \uf03d R1 \uf0a3 2 R1 1\uf02b tan \uf06aAN tan \uf06aMN ZC \uf02b R2 \uf028R1 \uf02b R2 \uf029 R2 \uf028R1 \uf02b R2 \uf029 ZC \uf0ec R1 \uf03d tan 36,870 \uf0de R1 \uf03d 3R2 R 2 ZC2 \uf0ef\uf0ef 2 \uf0ed 2 R2 \uf028R1 \uf02b R2 \uf029 \uf0de UMN \uf03d ZMN \uf03d \uf02b \uf03d 5 U Z 4 \uf0ef\uf0ef\uf0eeZC \uf03d R2 \uf028R1 \uf02b R2 \uf029 \uf03d 2R2 R1 \uf02b R2 \uf0de UMN \uf03d 55 5 \uf03d 123\uf028V\uf029 \uf0de Ch\u1ecdn A. M\u1ed8T \u0110I\u1ec6N \u00c1P HAI M\u1ea0CH C\u00d9NG R HAI D\u00d2NG \u0110I\u1ec6N C\u00d9NG BI\u00caN \u0110\u1ed8 B\u00e0i to\u00e1n g\u1ed1c: L\u1ea7n l\u01b0\u1ee3t \u0111\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u = U0cos(\u03c9t + \u03c6) (V) (U kh\u00f4ng \u0111\u1ed5i, \u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp RL1C1 v\u00e0 RL2C2 (L1, L2 thu\u1ea7n c\u1ea3m) th\u00ec bi\u1ec3u th\u1ee9c d\u00f2ng \u0111i\u1ec7n l\u00e0n l\u01b0\u1ee3t l\u00e0 i1 = Iocos(\u03c9t + \u03c6i1) (A) v\u00e0 i2 = I0cos(\u03c9t + \u03c6i2) (A). T\u00ecm qua h\u1ec7 c\u00e1c pha ban \u0111\u1ea7u v\u00e0 c\u00e1c \u0111\u1ed9 l\u1ec7ch pha. H\u01b0\u1edbng d\u1eabn * T\u1eeb I0 \uf03d U0 \uf03d U0 c\uf077s\uf06a \uf0beI\uf0be02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ec\uf0ee\uf0edi\uf06a21 \uf03d \uf06au \uf02d \uf06ai1 Z R \uf03d \uf06au \uf02d \uf06ai2 \uf0ef\uf0ecI0 \uf03d U0 cos \uf061 \uf0ef \uf03d R \uf0ef\uf0ef\uf0efP R \uf0ec\uf0ed\uf0ee\uf06a\uf06a12 \uf03d \uf061\uf03e 0 \uf0ec\uf0ef\uf0ef\uf06au \uf03d \uf06ai1 \uf02b \uf06ai2 1 I02 \uf03d \uf02d\uf061 \uf03c 2 2 * GS \uf0de \uf0ed \uf0de \uf0ed 0 \uf06ai1 \uf02d \uf06ai2 I0R \uf0ef\uf0ef\uf0ee\uf061 \uf03d \uf06a1 \uf03d \uf06a2 \uf03d 2 \uf0efU \uf03d cos \uf061 \uf0ef 0 \uf0ef \uf03d I0R cos \uf0e6 \uf077t \uf02b \uf06ai1 \uf02b \uf06ai2 \uf0f6 \uf0efu cos \uf061 \uf0e8\uf0e7 2 \uf0f7\uf0f8 \uf0ee\uf0ef C\u00e2u 159. (CD\u22122009) \u0110\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u c\u00f3 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng 60 V v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch R, L, C m\u1eafc n\u1ed1i ti\u1ebfp th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u0111o\u1ea1n m\u1ea1ch l\u00e0 i1 \uf03d I0 cos \uf028100\uf070t \uf02b \uf070 \/ 4 \uf029 (A). N\u1ebfu ng\u1eaft b\u1ecf t\u1ee5 \u0111i\u1ec7n C (n\u1ed1i t\u1eaft) th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u0111o\u1ea1n m\u1ea1ch l\u00e0 i2 \uf03d I0 cos \uf028100\uf070t \uf02d \uf070 \/ 12\uf029 (A). \u0110i\u1ec7n \u00e1p hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch l\u00e0 A. u \uf03d 60 2 cos \uf028100\uf070t \uf02d \uf070 \/12\uf029\uf028V\uf029. B. u \uf03d 60 2 cos \uf028100\uf070t \uf02d \uf070 \/ 6\uf029\uf028V\uf029. C. u \uf03d 60 2 cos \uf028100\uf070t \uf02b \uf070 \/ 12\uf029\uf028V\uf029. D. u \uf03d 60 2 cos \uf028100\uf070t \uf02b \uf070 \/ 6\uf029\uf028V\uf029. H\u01b0\u1edbng d\u1eabn * V\u00ec R kh\u00f4ng \u0111\u1ed5i m\u00e0 I01 \uf03d I02 \uf0de \uf06au \uf03d \uf06ai1 \uf02b \uf06ai2 \uf03d \uf070 \uf0de Ch\u1ecdn C. 2 12 C\u00e2u 160. M\u00f4t \u0111o\u1ea1n m\u1ea1ch xoay chi\u1ec1u g\u1ed3m cu\u1ed9n d\u00e2y c\u00f3 \u0111i\u1ec7n tr\u1edf thu\u1ea7n R, \u0111\u1ed9 t\u1ef1 c\u1ea3m L n\u1ed1i ti\u1ebfp v\u1edbi m\u1ed9t t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C \u0111\u1eb7t d\u01b0\u1edbi hi\u1ec7u \u0111i\u1ec7n th\u1ebf xoay chi\u1ec1u c\u00f3 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng \u1ed5n \u0111\u1ecbnh. C\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua m\u1ea1ch l\u00e0 i1 \uf03d 3 cos \uf028100\uf070t \uf029 (A). N\u1ebfu t\u1ee5 C b\u1ecb n\u1ed1i t\u1eaft th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua m\u1ea1ch l\u00e0 i2 \uf03d 3 cos \uf028100\uf070t \uf02d \uf070 \/ 3\uf029 (A). H\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t trong 2 tr\u01b0\u1eddng h\u1ee3p tr\u00ean l\u1ea7n l\u01b0\u1ee3t l\u00e0 A. cos \uf06a1 \uf03d 1;cos \uf06a2 \uf03d 0, 5. B. cos \uf06a1 \uf03d cos \uf06a2 \uf03d 0, 5. 3 C. cos \uf06a1 \uf03d cos \uf06a2 \uf03d 0, 75. D. cos \uf06a1 \uf03d cos \uf06a2 \uf03d 0, 5. H\u01b0\u1edbng d\u1eabn * V\u00ec R kh\u00f4ng \u0111\u1ed5i m\u00e0 I01 \uf03d I02 \uf06a1 \uf03d \uf06a2 \uf03d \uf061 \uf03d \uf06ai1 \uf02b \uf06ai2 \uf03d \uf070 2 6 \uf0de cos \uf06a1 \uf03d cos \uf06a2 \uf03d 3 \uf0de Ch\u1ecdn B 2 C\u00e2u 161. \u0110\u0103t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u \u1ed5n \u0111\u1ecbnh v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch C m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 100 \u03a9, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 c\u1ea3m kh\u00e1ng ZL v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 dung kh\u00e1ng ZC th\u00ec c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n qua \u0111o\u1ea1n m\u1ea1ch l\u00e0 i1 \uf03d I0 cos \uf028100\uf070t \uf02b \uf070 \/ 4 \uf029 (A). N\u1ebfu ng\u1eaft i2 \uf03d I0 cos \uf028100\uf070t \uf02b 3\uf070 \/ 4\uf029 (A). Dung kh\u00e1ng c\u1ee7a t\u1ee5 b\u1eb1ng A. 100 \u03a9. B. 200 \u03a9. C. 150 \u03a9. D. 50 \u03a9. H\u01b0\u1edbng d\u1eabn T\u1eeb I0 \uf03d U0 \uf03d U0 cos \uf06a \uf0beI\uf0be02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ee\uf0ed\uf0ec\uf06a\uf06a12 \uf03d \uf06au \uf02d \uf06ai1 \uf03d\uf061\uf03e 0 0 Z R \uf03d \uf06au \uf02d \uf06ai2 \uf03d \uf02d\uf061 \uf03c","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 * V\u00ec \uf06aRC \uf03d \uf06a2 \uf03d \uf02d\uf061 \uf03d\uf02d \uf06ai1 \uf02d \uf06ai2 \uf03d \uf02d \uf070 \uf0de ZC \uf03d R \uf03d 100\uf028\uf057\uf029 \uf0de Ch\u1ecdn A. 2 4 C\u00e2u 162. Cho ba linh ki\u1ec7n: \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 60 \u03a9, cu\u1ed9n c\u1ea3m thu\u1ea7n L v\u00e0 t\u1ee5 \u0111i\u1ec7n C. L\u1ea7n l\u01b0\u1ee3t \u0111\u1eadt \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u c\u00f3 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng u v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp RL ho\u1eb7c RC th\u00ec bi\u1ec3u th\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch l\u1ea7n l\u01b0\u1ee3t l\u00e0 i1 \uf03d 2 cos \uf028100\uf070t \uf02b \uf070 \/ 3\uf029\uf028A\uf029 v\u00e0 i2 \uf03d 2 cos \uf028100\uf070t \uf02b 7\uf070 \/ 12\uf029 (A). N\u1ebfu \u0111\u1eb7t \u0111i\u1ec7n \u00e1p tr\u00ean v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch RLC n\u1ed1i ti\u1ebfp th\u00ec d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch c\u00f3 bi\u1ec3u th\u1ee9c: A. i \uf03d 2 2 cos \uf028100\uf070t \uf02b \uf070 \/ 3\uf029\uf028A\uf029. B. i \uf03d 2 cos \uf028100\uf070t \uf02b \uf070 \/ 4\uf029 \uf028A \uf029. C. i \uf03d 2 2 cos \uf028100\uf070t \uf02b \uf070 \/ 4\uf029\uf028A\uf029. D. i \uf03d 2 cos \uf028100\uf070t \uf02b \uf070 \/ 3\uf029\uf028A \uf029. H\u01b0\u1edbng d\u1eabn * T\u1eeb I0 \uf03d U0 \uf03d U0 cos \uf06a \uf0be\uf0beI02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ef\uf0ec\uf06a1 \uf03d \uf06a\uf06d \uf02d \uf06ai1 Z R \uf0ef\uf0ee\uf0ed\uf06a2 \uf03d \uf06au \uf02d \uf06ai2 \uf03d\uf061\uf03e0 \uf0ef\uf0ef\uf0ec\uf06au \uf03d \uf06ai1 \uf02b \uf06ai2 \uf03d \uf070 \uf03d \uf02d\uf061 \uf03c 0 2 \uf03d 4 \uf0de \uf0ed\uf0ee\uf0ec\uf06a\uf06a12 \uf0de \uf0ed \uf06ai1 \uf02d \uf06ai2 \uf070 \uf0ee\uf0ef\uf0ef\uf061 \uf03d \uf06a1 \uf03d \uf06a2 2 \uf03d 3 \uf0ec ZL \uf03d ZC \uf03d R 3 \uf0ef I0R cos \uf0de \uf0ef\uf0edu \uf03d cos \uf061 \uf0e6 \uf06ai1 \uf02b \uf06ai 2 \uf0f6 \uf0e6\uf0e8\uf0e7100\uf070t \uf070 \uf0f6 \uf0e7\uf0e8 \uf077t \uf02b 2 \uf0f8\uf0f7 \uf03d 120 2 cos \uf02b 4 \uf0f8\uf0f7 \uf028 V\uf029 \uf0ee * M\u1ea1ch RLC c\u1ed9ng h\u01b0\u1edfng n\u00ean i \uf03d u \uf03d 2 2 cos\uf0e7\uf0e6\uf0e8100\uf070t \uf02b \uf070 \uf0f6 \uf028A\uf029 \uf0de Ch\u1ecdn C. R 4 \uf0f7\uf0f8 C\u00e2u 163. Cho ba linh ki\u1ec7n: \u0111i\u1ec7n tr\u1edf thu\u1ea7n R \uf03d 30 3 \uf057 cu\u1ed9n c\u1ea3m thu\u1ea7n L v\u00e0 t\u1ee5 \u0111i\u1ec7n C. L\u1ea7n l\u01b0\u1ee3t \u0111\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u c\u00f3 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng u v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp RL ho\u1eb7c RC th\u00ec bi\u1ec3u th\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch l\u1ea7n l\u01b0\u1ee3t l\u00e0 i1 \uf03d 2 3 cos \uf028100\uf070t \uf02d \uf070 \/ 12\uf029 (A) v\u00e0 i2 \uf03d 2 3 cos \uf028100\uf070t \uf02b 5\uf070 \/ 12\uf029 (A). N\u1ebfu \u0111\u1eb7t \u0111i\u1ec7n \u00e1p tr\u00ean v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch RLC n\u1ed1i ti\u1ebfp th\u00ec bi\u1ec3u th\u1ee9c \u0111i\u1ec7n \u00e1p tr\u00ean L l\u00e0 A. uL \uf03d 120 6 cos \uf028100\uf070t \uf02b \uf070 \/ 2\uf029 \uf028V\uf029. B. uL \uf03d 120 3 cos \uf028100\uf070t \uf02b 2\uf070 \/ 3\uf029 \uf028V\uf029. C. uL \uf03d 120 2 cos \uf028100\uf070t \uf02b \uf070 \/ 3\uf029 \uf028V\uf029. D. uL \uf03d 180 2 cos \uf028100\uf070t \uf02b 2\uf070 \/ 3\uf029 \uf028V\uf029. H\u01b0\u1edbng d\u1eabn * T\u1eeb I0 \uf03d U0 \uf03d U0 cos \uf06a \uf0beI\uf0be02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ec\uf0ef\uf06a1 \uf03d \uf06a\uf06d \uf02d \uf06ai1 Z R \uf0ef\uf0ed\uf0ee\uf06a2 \uf03d \uf06au \uf02d \uf06ai2 \uf0ec\uf0ed\uf0ee\uf06a\uf06a12 \uf03d\uf061\uf03e0 \uf0ef\uf0ec\uf0ef\uf06au \uf03d \uf06ai1 \uf02b \uf06ai2 \uf03d \uf070 \uf03d \uf02d\uf061 \uf03c 2 \uf03d 6 \uf0de \uf0de \uf0ed \uf06ai1 0 \uf02d \uf06ai2 \uf070 \uf0ef\uf0ee\uf0ef\uf061 \uf03d \uf06a1 \uf03d \uf06a2 2 \uf03d 4 \uf0de ZL \uf03d ZC \uf03d R \uf0de u \uf03d I0R cos \uf0e6 \uf077t \uf02b \uf06ai1 \uf02b \uf06ai2 \uf0f6 \uf03d 180 2 cos \uf0e7\uf0e6\uf0e8100\uf070t \uf02b \uf070 \uf0f6 \uf028V\uf029 cos \uf061 \uf0e7\uf0e8 2 \uf0f7\uf0f8 6 \uf0f8\uf0f7 * M\u1ea1ch RLC c\u1ed9ng h\u01b0\u1edfng n\u00ean i \uf03d u \uf03d 2 6 cos \uf0e8\uf0e7\uf0e6100\uf070t \uf02b \uf070 \uf0f6 \uf028 A \uf029 R 6 \uf0f8\uf0f7 uL \uf03d ZL.2 6 cos \uf0e8\uf0e7\uf0e6100\uf070t \uf02b \uf070 \uf02b \uf070 \uf0f6 \uf028 V \uf029 \uf03d 180 2 cos \uf0e7\uf0e6\uf0e8100\uf070t \uf02b 2\uf070 \uf0f6 \uf028 V \uf029 \uf0de Ch\u1ecdn D. 6 2 \uf0f8\uf0f7 3 \uf0f8\uf0f7 C\u00e2u 164. Cho ba linh ki\u1ec7n: \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 30 \u03a9, cu\u1ed9n c\u1ea3m thu\u1ea7n L v\u00e0 t\u1ee5 \u0111i\u1ec7n C. L\u1ea7n l\u01b0\u1ee3t \u0111\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u = U0cos(\u03c9t + \u03c6u) (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp RL ho\u1eb7c RC th\u00ec bi\u1ec3u th\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch l\u1ea7n l\u01b0\u1ee3t l\u00e0 i1 \uf03d 6 cos \uf028\uf077t \uf02b \uf070 \/ 7\uf029 (A) v\u00e0 i2 \uf03d 6 cos \uf028\uf077t \uf02b 10\uf070 \/ 21\uf029 (A). N\u1ebfu \u0111\u1eb7t \u0111i\u1ec7n \u00e1p tr\u00ean v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch RLC n\u1ed1i ti\u1ebfp th\u00ec c\u00f4ng su\u1ea5t m\u1ea1ch \u0111i\u1ec7n \u0111\u00f3 ti\u00eau th\u1ee5 l\u00e0: A. 960 W. B. 720 W. C. 480 W. D. 240 W. H\u01b0\u1edbng d\u1eabn * T\u1eeb I0 \uf03d U0 \uf03d U0 cos \uf06a \uf0be\uf0beI02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ef\uf0ec\uf06a1 \uf03d \uf06a\uf06d \uf02d \uf06ai1 Z R \uf0ef\uf0ee\uf0ed\uf06a2 \uf03d \uf06au \uf02d \uf06ai2 \uf0de \uf0ed\uf0ec\uf0ee\uf06a\uf06a12 \uf03d \uf061\uf03e 0 0 \uf0de \uf061 \uf03d \uf06a1 \uf03d \uf06a2 \uf03d \uf06ai1 \uf02d \uf06ai2 \uf03d \uf02d\uf061 \uf03c 2 \u00c1P D\u1ee4NG:","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 * \uf06a1 \uf03d \uf06a2 \uf03d \uf06ai1 \uf02d \uf06ai2 \uf03d \uf070 \uf0de \uf0ec\uf0efZL \uf03d ZC \uf03d 120 3\uf028V\uf029 2 6 \uf0ee\uf0ef\uf0edU0 \uf03d I0R cos \uf061 * M\u1ea1ch RLC c\u1ed9ng h\u01b0\u1edfng n\u00ean P \uf03d U2 \uf03d 720W \uf0de Ch\u1ecdn B. R C\u00e2u 165. Cho ba linh ki\u1ec7n: \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 10 \u03a9, cu\u1ed9n c\u1ea3m thu\u1ea7n L v\u00e0 t\u1ee5 \u0111i\u1ec7n C. L\u1ea7n l\u01b0\u1ee3t \u0111\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u \uf03d U 0 cos \uf028\uf077t \uf02b \uf06au \uf029 (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp RL ho\u1eb7c RC th\u00ec bi\u1ec3u th\u1ee9c c\u01b0\u1eddng \u0111\u1ed9 d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch l\u1ea7n l\u01b0\u1ee3t l\u00e0 i1 \uf03d 4 2 cos \uf028\uf077t \uf02b \uf070 \/ 7\uf029 (A) v\u00e0 i2 \uf03d 4 2 cos \uf028\uf077t \uf02b10\uf070 \/ 21\uf029 (A). N\u1ebfu \u0111\u1eb7t \u0111i\u1ec7n \u00e1p tr\u00ean v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch RLC n\u1ed1i ti\u1ebfp th\u00ec c\u00f4ng su\u1ea5t m\u1ea1ch \u0111i\u1ec7n \u0111\u00f3 ti\u00eau th\u1ee5 l\u00e0: A. 640 W B. 480 W. C. 213 W. D. 240W. H\u01b0\u1edbng d\u1eabn * T\u1eeb I0 \uf03d U0 \uf03d U0 cos \uf06a \uf0be\uf0beI02 \uf03d\uf0beI01 \uf0ae cos \uf06a2 \uf03d cos \uf06a1 \uf0de \uf06a2 \uf03d \uf02d\uf06a1 \uf0ef\uf0ec\uf06a1 \uf03d \uf06a\uf06d \uf02d \uf06ai1 Z R \uf0ee\uf0ed\uf0ef\uf06a2 \uf03d \uf06au \uf02d \uf06ai2 \uf0de \uf0ec\uf0ee\uf0ed\uf06a\uf06a12 \uf03d \uf061\uf03e 0 0 \uf0de \uf061 \uf03d \uf06a1 \uf03d \uf06a2 \uf03d \uf06ai1 \uf02d \uf06ai2 \uf03d \uf02d\uf061 \uf03c 2 \u00c1P D\u1ee4NG: * \uf06a1 \uf03d \uf06a2 \uf03d \uf06ai1 \uf02d \uf06ai2 \uf03d \uf070 \uf0de \uf0ef\uf0ecZL \uf03d ZC \uf03d 80 6 \uf028V\uf029 2 6 \uf0ed\uf0ef\uf0eeU0 \uf03d 3 I0R cos \uf061 * M\u1ea1ch RLC c\u1ed9ng h\u01b0\u1edfng n\u00ean P \uf03d U2 \uf03d 213W \uf0de Ch\u1ecdn C. R \u0110\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 1: Khi R thay \u0111\u1ed5i R XB A \uf0ec \uf028 \uf029 \uf028 \uf029\uf0ef\uf0efPR max \uf03d2 U2 \uf0db R \uf03d Zcon lai \uf03d R 2 \uf02b ZLX \uf02d ZCX 2 R \uf02bRX X \uf028 \uf029\uf0ef U2 R \uf02b RX \uf0ef\uf0edR X \uf0ef \uf03c ZLX \uf02d ZCX : P\uf028R \uf02b RX \uf029 max \uf03d2 \uf0db R \uf02b R X Zcon lai \uf03d ZLX \uf02d ZCX \uf0ef U2RX ZLX \uf02d ZCX \uf028 \uf029\uf0efR :P \uf0db R \uf03d0 \uf028 \uf029\uf0ef\uf0ee X \uf0b3 ZLX \uf02d ZCX R \uf02b RX max \uf03d R 2 \uf02b 2 X C\u00e2u 166. \u0110\u0103t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u = U0cos\u03c9t (V) (U0 v\u00e0 \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB theo th\u1ee9 t\u1ef1 g\u1ed3m bi\u1ebfn tr\u1edf R, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi R = 30 \u03a9 th\u00ec c\u00f4ng su\u1ea5t m\u1ea1ch ti\u00eau th\u1ee5 l\u00e0 P. Khi R = 40 \u03a9 th\u00ec c\u00f4ng su\u1ea5t m\u1ea1ch ti\u00eau th\u1ee5 m\u1ea1ch c\u1ef1c \u0111\u1ea1i l\u00e0 Pmax. T\u1ec9 s\u1ed1 P\/Pmax b\u1eb1ng A. 3\/4. B. 12\/25. C. 16\/26. D. 24\/25. H\u01b0\u1edbng d\u1eabn U2R \uf0ec\uf0efP \uf03d U2R1 P 2R1R 2 24 R 2 \uf02b Z2LC \uf0ef R12 \uf02b Z2LC Pmax R12 \uf02b Z2LC 25 * T\u1eeb P\uf03d \uf0de \uf0ed \uf0de \uf03d \uf03d U2 \uf0ee\uf0ef\uf0efPmax \uf0db R 2 \uf03d ZLC \uf0db Pmax \uf03d 2R 2 \uf0de Ch\u1ecdn D. C\u00e2u 167. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf028\uf077t \uf02b \uf06au \uf029 (U, \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB n\u1ed1i ti\u1ebfp g\u1ed3m bi\u1ebfn tr\u1edf R v\u00e0 cu\u1ed9n c\u1ea3m kh\u00f4ng thu\u1ea7n c\u1ea3m. Khi R = R0 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean R b\u1eb1ng \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean cu\u1ed9n d\u00e2y b\u1eb1ng nhau. Sau \u0111\u00f3 t\u0103ng R t\u1eeb gi\u00e1 tr\u1ecb R0 th\u00ec A. d\u00f2ng hi\u1ec7u d\u1ee5ng t\u0103ng r\u1ed3i gi\u1ea3m. B. c\u00f4ng su\u1ea5t m\u1ea1ch AB t\u0103ng r\u1ed3i gi\u1ea3m, C. c\u00f4ng su\u1ea5t tr\u00ean R t\u0103ng r\u1ed3i gi\u1ea3m. D. c\u00f4ng su\u1ea5t tr\u00ean R gi\u1ea3m. H\u01b0\u1edbng d\u1eabn * C\u01a1 s\u1edf n\u1ec1n t\u1ea3ng: R \uf045 PR max \uf03d U2 \uf0db R0 \uf03d ZrL \uf0db UR0 \uf03d UrL R0 \uf02b r T\u1ea1i R = R0 th\u00ec PRmax n\u00ean sau \u0111\u00f3 c\u00f4ng su\u1ea5t tr\u00ean R s\u1ebd gi\u1ea3m => Ch\u1ecdn D. C\u00e2u 168. \u0110\u0103t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u \u1ed5n \u0111\u1ecbnh v\u00e0o hai \u0111\u00e0u \u0111o\u1ea1n m\u1ea1ch kh\u00f4ng ph\u00e2n nh\u00e1nh AB theo th\u1ee9 t\u1ef1: bi\u1ebfn tr\u1edf R, cu\u1ed9n d\u00e2y c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L c\u00f3 \u0111i\u1ec7n tr\u1edf r, t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C v\u00e0 M l\u00e0 \u0111i\u1ec3m n\u1ed1i gi\u1eefa R v\u00e0 cu\u1ed9n d\u00e2y. Khi \u0111i\u1ec1u ch\u1ec9nh bi\u1ebfn tr\u1edf R thay \u0111\u1ed5i \u0111\u1ec3 c\u00f4ng su\u1ea5t ti\u00eau th\u1ee5 tr\u00f4n bi\u1ebfn tr\u1edf c\u1ef1c \u0111\u1ea1i th\u00ec UAB = 1,6UAM. L\u00fac n\u00e0y, t\u1ef7 s\u1ed1 c\u00f4ng su\u1ea5t c\u1ee7a cu\u1ed9n d\u00e2y v\u00e0 c\u00f4ng su\u1ea5t c\u1ee7a bi\u1ebfn tr\u1edf l\u00e0? A. 37,5%. B. 100%. C. 28%. D. 35%.","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 H\u01b0\u1edbng d\u1eabn 0, 5U B 0, 5U U LCr \uf072 \uf06a \uf06aMB A \uf075\uf072 I UR M PR max \uf0db R \uf03d ZLCr \uf0de cos \uf06a \uf03d 0, 5U \uf03d 0, 8 \uf0de cos \uf06aMB \uf03d 2 cos2 \uf06a \uf02d1 \uf03d 0, 28 UAM \uf0de PLCr \uf03d UMBI cos \uf06aMB \uf03d 0, 28 \uf03d 0, 28 \uf0de Ch\u1ecdn C. PR UAMI cos \uf06aAM 1 KINH NGHI\u1ec6M D\u00d9NG TN1 \u0110\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: 1) Khi L thay \u0111\u1ed5i: U \uf0ef\uf0ecUL max \uf0db \uf02d1 \uf03d tan \uf06a tan \uf06aRC \uf0db ZL \uf03d R 2 \uf02b ZC2 \uf0ef ZC UL\uf028RL\uf029 max \uf03d \uf0ed ZC \uf0ee\uf0ef\uf0efURL max ZC \uf02b ZC2 \uf02b 4R 2 1\uf02d ZL \uf0db \uf02b1 \uf03d tan \uf06a tan \uf06aRL \uf0db ZL \uf03d 2 2) Khi C thay \u0111\u1ed5i: U \uf0ef\uf0ec U C max \uf0db \uf02d1 \uf03d tan \uf06a tan \uf06aRL \uf0db ZC \uf03d R 2 \uf02b ZL2 \uf0ef ZL UC\uf028RC\uf029 max \uf03d \uf0ed ZL \uf0ef\uf0ee\uf0efURC max ZL \uf02b ZL2 \uf02b 4R 2 1\uf02d ZC \uf0db \uf02b1 \uf03d tan \uf06a tan \uf06aRC \uf0db ZC \uf03d 2 C\u00e2u 169. \u0110\u0103t v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n d\u00e2y c\u00f3 \u0111i\u1ec7n tr\u1edf r, c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C m\u1ed9t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u \u1ed5n \u0111\u1ecbnh. N\u1ebfu r \uf03d ZC 3 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean cu\u1ed9n d\u00e2y c\u1ef1c \u0111\u1ea1i khi c\u1ea3m kh\u00e1ng l\u00e0 A. ZL = ZC. B. ZL = 2ZC. C. ZL = 0,5ZC. D. ZL = 1,5ZC. H\u01b0\u1edbng d\u1eabn * Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: UrL max \uf0db 1 \uf03d tan \uf06a tan \uf06arL \uf03d ZL \uf02d ZC ZL \uf0ber\uf0be\uf03d0,\uf0be5 3Z\uf0beC \uf0ae ZL \uf03d 1,5ZC r r C\u00e2u 170. \u0110\u1eb7t m\u1ed9t \u0111i\u1ec7n \u00e1p U = U0 cos\u03c9t (V) v\u00e0o 2 \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB theo th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf thu\u1ea7n R, t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c v\u00e0 cu\u1ed9n thu\u1ea7n c\u1ea3m c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L m\u1eafc n\u1ed1i ti\u1ebfp theo \u0111\u00fang th\u1ee9 t\u1ef1 tr\u00ean. G\u1ecdi M l\u00e0 \u0111i\u1ec3m n\u1ed1i gi\u1eefa t\u1ee5 \u0111i\u1ec7n v\u00e0 cu\u1ed9n thu\u1ea7n c\u1ea3m. Khi \u0111i\u1ec1u ch\u1ec9nh 60 3 (V). H\u1ecfi U0 c\u00f3 gi\u00e1 tr\u1ecb b\u1eb1ng bao nhi\u00eau? A. 120 2 (V). B. 120 (V). C. 60 3 (V). D. 60 2 (V). H\u01b0\u1edbng d\u1eabn * Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: URCmax \uf03d U \uf0be\uf0be\uf0be\uf0be\uf0be\uf0be\uf0ae UURCmaxs \uf03d60 3 \uf03d 60 \uf0de U0 \uf03d 60 2 1 \uf02d ZL C0 \uf03d 3 2 \uf0de ZL \uf03d 2 ZC L\uf0772 ZC 3 C\u00e2u 171. \u0110\u0103t \u0111i\u1ec7n \u00e1p U = U0cos100\u03c0t (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. Khi \u0111i\u1ec1u ch\u1ec9nh C \u0111\u1ec3 ZC = 1,5ZL th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean \u0111o\u1ea1n RC c\u1ef1c \u0111\u1ea1i v\u00e0 b\u1eb1ng 60 3 (V). T\u00ecm U0. A. 120 V. B. 120 2 V. C. 60 2 V. D. 60 4 V. H\u01b0\u1edbng d\u1eabn Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: URC max \uf03d U \uf0be\uf0be\uf0be\uf0be\uf0be\uf0ae UURCmax \uf03d60 3 \uf03d 60 \uf0de U0 \uf03d 60 2 \uf0de Ch\u1ecdn C. ZC \uf03d1,5ZL ZL 1\uf02d ZC C\u00e2u 172. \u0110\u0103t \u0111i\u1ec7n \u00e1p u = U0cos100\u03c0t (V) (U0 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111\u01b0\u1ee3c, \u0111i\u1ec7n tr\u1edf R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi \u0111i\u1ec1u ch\u1ec9nh L \u0111\u1ec3 c\u00e0m kh\u00e1ng b\u1eb1ng 1,25 l\u1ea7n dung kh\u00e1ng th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean \u0111o\u1ea1n RL c\u1ef1c \u0111\u1ea1i v\u00e0 b\u1eb1ng 50 5 V. Gi\u00e1 tr\u1ecb U0 l\u00e0 A. 60 3 V. B. 120 V. C. 60 2 D. 50 2 . H\u01b0\u1edbng d\u1eabn","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: URL max \uf03d U \uf0db 50 5\uf03d U0 \/ 2 \uf0de U0 \uf03d 50 2 \uf0de Ch\u1ecdn D. 1\uf02d ZC 1 \uf02d 1 ZL 1, 25 C\u00e2u 173. \u0110\u0103t \u0111i\u1ec7n \u00e1p u = U0cos100\u03c0t (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB gh\u00e9p n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u00f4m \u0111i\u1ec7n tr\u1edf thu\u1ea7n R, cu\u1ed9n c\u1ea3m thu\u1ea7n L v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. \u0110i\u1ec1u ch\u1ec9nh C \u0111\u1ec3 \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean t\u1ee5 c\u1ef1c \u0111\u1ea1i th\u00ec gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i b\u1eb1ng U 0 2, 5 v\u00e0 l\u00fac n\u00e0y dung kh\u00e1ng nhi\u1ec1u h\u01a1n c\u1ea3m kh\u00e1ng l\u00e0 50 \u03a9. T\u00ednh L. A. 2,5\/\u03c0 H. B. 1,5\/\u03c0 H. C. 1\/\u03c0 H. D. 2\/\u03c0 H. H\u01b0\u1edbng d\u1eabn \u0110\u1ecbnh l\u00fd TN2: UCmax \uf03d U \uf0dbU 5\uf03d U \uf0de ZL \uf03d 200 \uf028 \uf057 \uf029 ZL 1\uf02d ZC 1\uf02d ZL ZL \uf02b 50 \uf0de L \uf03d ZL \uf03d 2 \uf028H\uf029 \uf0de Ch\u1ecdn D. \uf077\uf070 C\u00e2u 174. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U, \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m \u0111o\u1ea1n AM ch\u1ee9a \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 90 \u03a9, \u0111o\u1ea1n MB ch\u1ee9a cu\u1ed9n c\u1ea3m c\u00f3 \u0111i\u1ec7n tr\u1edf thu\u1ea7n r = 10 \u03a9 c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L n\u1ed1i ti\u1ebfp v\u1edbi t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. Khi C = C1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean MB c\u1ef1c ti\u1ec3u v\u00e0 b\u1eb1ng U1. Khi C = C2 = C1\/2 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean t\u1ee5 c\u1ef1c \u0111\u1ea1i v\u00e0 b\u1eb1ng U2. T\u00ednh U2\/U1. A. 9 2. B. 2. C. 10 2. D. 5 2 H\u01b0\u1edbng d\u1eabn r2 \uf02b \uf028 ZL \uf02d ZC1 \uf0292 r \uf028 r \uf02b R \uf0292 \uf02d ZL \uf02d ZC1 r\uf02bR \uf028 \uf029* Khi C \uf03d C1 t\u1eeb UMB \uf03d U 2 \uf03d min \uf03d U \uf03d 0,1U \uf03d U1 * Khi C \uf03d C2 \uf03d C1 \/ 2 \uf0de ZC2 \uf03d 2ZC1 \uf03d 2ZL theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: U2 \uf03d UC max \uf03d U \uf03dU 2 \uf03d 10 2U1 \uf0de Ch\u1ecdn C. ZL 1\uf02d ZC2 C\u00e2u 175. \u0110\u0103t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u = U0cos\u03c9t (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB theo th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf thu\u1ea7n R = 90 (\u03a9), cu\u1ed9n c\u1ea3m c\u00f3 \u0111i\u1ec7n tr\u1edf r = 10 (\u03a9) v\u00e0 c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. G\u1ecdi M l\u00e0 \u0111i\u1ec3m n\u1ed1i gi\u1eefa R v\u00e0 cu\u1ed9n d\u00e2y. Khi C = C1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch MB \u0111\u1ea1t gi\u00e1 tr\u1ecb c\u1ef1c ti\u1ec3u b\u1eb1ng U1. Khi C = C2 = 0,75C1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng hai \u0111\u1ea7u t\u1ee5 \u0111i\u1ec7n \u0111\u1ea1t gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i b\u1eb1ng U2. T\u1ec9 s\u1ed1 U2\/U1 b\u1eb1ng A. 5\/2. B.10 2 . C. 10 2. D. 2 H\u01b0\u1edbng d\u1eabn * T\u1eeb UrLC \uf03d U R2 \uf02b ZL2C \uf03d min \uf03d U R r r \uf03d 0,1U \uf03d U1 \uf0db ZC1 \uf03d ZL \uf02b \uf028 R \uf02b r\uf0292 \uf02b Z2LC * Theo \u0111\u1ecbnh l\u00fd TN2: U2 \uf03d UC max \uf03d U \uf03d U \uf03d 2U \uf0de U2 \uf03d 20 ZL .0, 75 U1 1\uf02d ZL 1\uf02d ZC1 ZC2 \uf0de Ch\u1ecdn D. C\u00e2u 176. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U v\u00e0 \u03c9 kh\u00f4ng \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB n\u1ed1i ti\u1ebfp g\u1ed3m \u0111o\u1ea1n AM ch\u1ee9a \u0111i\u1ec7n tr\u1edf R = 90 \u03a9 v\u00e0 \u0111o\u1ea1n MB ch\u1ee9a cu\u1ed9n c\u1ea3m c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L c\u00f3 \u0111i\u1ec7n tr\u1edf r = 10 \u03a9 n\u1ed1i ti\u1ebfp v\u1edbi t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C thay \u0111\u1ed5i \u0111\u01b0\u1ee3c. Khi C = Cl th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean \u0111o\u1ea1n MB c\u1ef1c ti\u1ec3u v\u00e0 b\u1eb1ng U1. Khi C = C2 = 0,5C1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean t\u1ee5 c\u1ef1c \u0111\u1ea1i v\u00e0 b\u1eb1ng U2. T\u00ecm t\u1ec9 s\u1ed1 U2\/U1. A. 9\/2. B. 5\/2 . C.10 2 . D. 2 . (S\u1edf GD Qu\u00e3ng Ng\u00e3i) H\u01b0\u1edbng d\u1eabn * T\u1eeb UMB \uf03d IZMB \uf03d U r2 \uf02b \uf028ZL \uf02d ZC \uf0292 \uf03d min \uf03d Ur U \uf03d U1 \uf0db ZC1 \uf03d ZL \uf028r \uf02b R \uf0292 \uf02b \uf028ZL \uf02d ZC \uf0292 r\uf02bR \uf03d 10 Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: U2 \uf03d UCmax \uf03d U \uf03dU 2 \uf0de U2 \uf03d 10 2\uf0de Ch\u1ecdn C. ZL U1 1\uf02d ZC2 C\u00e2u 177. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U v\u00e0 \u03c9) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m \u0111o\u1ea1n AM ch\u1ee9a cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L thay \u0111\u1ed5i \u0111u\u1ee3c n\u1ed1i ti\u1ebfp \u0111i\u1ec7n tr\u1edf R v\u00e0 \u0111o\u1ea1n MB ch\u1ee9a t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi L = L1 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean MB l\u00e0 100 V, d\u00f2ng trong m\u1ea1ch c\u00f3 gi\u00e1 tr\u1ecb hi\u1ec7u d\u1ee5ng 0,5 A v\u00e0 tr\u1ec5 pha so v\u1edbi u l\u00e0 60\u00b0. T\u00ecm L \u0111\u1ec3 \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean AM c\u1ef1c \u0111\u1ea1i.","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 \uf028 \uf029 \uf028 \uf029A. 1\uf02b 2 \/ \uf070\uf028H\uf029. B. 1\uf02b 3 \/ \uf070\uf028H\uf029. \uf028 \uf029C. 2 \uf02b 3 \/ \uf070\uf028H\uf029. D. 2, 5 \/ \uf070 \uf028H \uf029. H\u01b0\u1edbng d\u1eabn Khi L = L1 th\u00ec tam gi\u00e1c AMB c\u00e2n t\u1ea1i B n\u00ean suy ra: M \uf061 \uf0de \uf061 \uf03d 750 \uf0de \uf0ef\uf0ec U L \uf03d 100 \uf02d 50 3 \uf0de \uf0ee\uf0ec\uf0edRZC\uf03d\uf03d102000 \uf075\uf072 \uf0ed U R \uf03d UL tan \uf061 \uf03d 50 URL \uf075\uf072 \uf0ee\uf0ef UC \uf061 *Theo \u0111\u1ecbnh l\u00fd th\u1ed1ng nh\u1ea5t 2: A 600 \uf062 B URLmax khi tan \uf06a. tan \uf06aRL \uf03d 1 \uf075\uf072 U ZL \uf02d ZC . ZL \uf03d1\uf0de ZL \uf03d1\uf02b 2 \uf0de L \uf03d 1\uf02b 2 \uf028H\uf029 RR R \uf070 \uf0de Ch\u1ecdn A. KINH NGHI\u1ec6M D\u00d9NG BHD1 GI\u1ea2I B\u00c0I TO\u00c1N \u1ede M\u1ee8C V\u1eacN D\u1ee4NG CAO \u0110\u1ecbnhl\u00ed BHD1:1) UC \uf03d max \uf0db ZL \uf03d Z\uf074 (\u201cCmax \uf0de L t\u1ed3\u201d) 2) UL \uf03d max \uf0db ZC \uf03d Z\uf074 (\u201cL max \uf0de C t\u1ed3\u201d) C\u00e2u 178. (340325BT) \u0110\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u \uf03d U 2 cos \uf028\uf077t \uf02b \uf06a\uf029 (V) (U kh\u00f4ng \u0111\u1ed5i v\u00e0 \u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m \u0111i\u1ec7n tr\u1edf R, t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C, cu\u1ed9n d\u00e2y thu\u1ea7n c\u1ea3m c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L sao cho 2L > R2C. Khi \uf077 \uf03d \uf0771 th\u00ec m\u1ea1ch x\u1ea3y ra c\u1ed9ng h\u01b0\u1edfng. Khi \uf077 \uf03d \uf0772 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean t\u1ee5 c\u1ef1c \u0111\u1ea1i. Khi \uf077 \uf03d \uf0773 th\u00ec h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t c\u1ee7a m\u1ea1ch AB l\u00e0 cos\u03c6. N\u1ebfu \uf028 \uf029 \uf028 \uf029\uf07712 \uf02d \uf07732 2 \uf03d 3\uf07732 \uf07712 \uf02d \uf07722 th\u00ec cos \uf06a g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 0,5. B. 0,8. C. 0,6. D. 0,7. H\u01b0\u1edbng d\u1eabn V\u1edbi b\u00e0i to\u00e1n cho m\u1ed9t h\u1ec7 th\u1ee9c li\u00ean h\u1ec7 gi\u1eefa c\u00e1c t\u1ea7n s\u1ed1 y\u00eau c\u1ea7u t\u00ednh h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t (c\u00f4ng su\u1ea5t, d\u00f2ng \u0111i\u1ec7n,..) thu\u1ed9c lo\u1ea1i b\u00e0i to\u00e1n \u201cc\u1eedu v\u1ea1n\u201d d\u00f9ng c\u01a1 b\u1eafp bi\u1ebfn \u0111\u1ed5i \u0111\u1ea1i s\u1ed1 t\u1eeb h\u1ec7 th\u1ee9c \u0111\u00f3 l\u00e0 xong. \uf0ef\uf0ef\uf0ec\uf07712 \uf03d 1 LC \uf0ed \uf0ef L R2 1 R2 R2 \uf0ee\uf0ef U C max \uf0db \\\"L to\\\" \uf0db \uf0772 L \uf03d Z\uf074 \uf03d C\uf02d 2 \uf0de \uf07722 \uf03d LC \uf02d 2L2 \uf0de \uf07712 \uf02d \uf07722 \uf03d 2L2 Thay v\u00e0o h\u1ec7 th\u1ee9c \u0111\u00e3 cho: \uf0e6 1 \uf02d \uf07732 \uf0f62 \uf03d 2\uf07732 R2 \uf0db 1 \uf02d \uf0773L \uf03dR \uf0de cos \uf06a \uf03d 1 \uf0de Ch\u1ecdn D. \uf0e8\uf0e7 LC \uf0f7\uf0f8 2L2 \uf0773C 2 C\u00e2u 179. (340326BT) \u0110\u1eb7t \u0111i\u1ec7n \u00e1p xoay chi\u1ec1u u \uf03d U 2 cos \uf028\uf077t \uf02b \uf06a\uf029 (V) (U kh\u00f4ng \u0111\u1ed5i v\u00e0 \u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m \u0111i\u1ec7n tr\u1edf R, t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C, cu\u1ed9n d\u00e2y thu\u1ea7n c\u1ea3m c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L sao cho 2L > R2C. Khi \uf077 \uf03d \uf0771 th\u00ec m\u1ea1ch x\u1ea3y ra c\u1ed9ng h\u01b0\u1edfng. Khi \uf077 \uf03d \uf0772 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean t\u1ee5 c\u1ef1c \u0111\u1ea1i. Khi \uf077 \uf03d \uf0773 th\u00ec h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t c\u1ee7a m\u1ea1ch AB l\u00e0 cos\u03c6. N\u1ebfu \uf028 \uf029 \uf028 \uf029\uf07712 \uf02d \uf07732 2 \uf03d 1,125\uf07732 \uf07712 \uf02d \uf07722 th\u00ec cos \uf06a g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 0,5. B. 0,8. C. 0,6. D. 0,7. H\u01b0\u1edbng d\u1eabn V\u1edbi b\u00e0i to\u00e1n cho m\u1ed9t h\u1ec7 th\u1ee9c li\u00ean h\u1ec7 gi\u1eefa c\u00e1c t\u1ea7n s\u1ed1 y\u00eau c\u1ea7u t\u00ednh h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t (c\u00f4ng su\u1ea5t, d\u00f2ng \u0111i\u1ec7n,..) thu\u1ed9c lo\u1ea1i b\u00e0i to\u00e1n \u201cc\u1eedu v\u1ea1n\u201d d\u00f9ng c\u01a1 b\u1eafp bi\u1ebfn \u0111\u1ed5i \u0111\u1ea1i s\u1ed1 t\u1eeb h\u1ec7 th\u1ee9c \u0111\u00f3 l\u00e0 xong. \uf0ef\uf0ef\uf0ec\uf07712 \uf03d 1 LC \uf0ed \uf0ef L R2 1 R2 R2 \uf0ee\uf0ef U C max \uf0db \\\"L to\\\" \uf0db \uf0772 L \uf03d Z\uf074 \uf03d C\uf02d 2 \uf0de \uf07722 \uf03d LC \uf02d 2L2 \uf0de \uf07712 \uf02d \uf07722 \uf03d 2L2 Thay v\u00e0o h\u1ec7 th\u1ee9c \u0111\u00e3 cho: \uf0e6 1 \uf02d \uf07732 \uf0f62 \uf03d 2\uf07732 R2 \uf0db 1 \uf02d \uf0773 L \uf03d 0, 75R \uf0de cos \uf06a \uf03d 0,8 \uf0de Ch\u1ecdn B. \uf0e7\uf0e8 LC \uf0f8\uf0f7 2L2 \uf0773C KINH NGHI\u1ec6M D\u00d9NG BHD4 GI\u1ea2I B\u00c0I TO\u00c1N \u1ede M\u1ee8C \u0110\u1ed8 V\u1eacN D\u1ee4NG CAO \u0110\u1ecbnh l\u00fd BHD 4: Khi \u03c9 thay \u0111\u1ed5i, \u0111\u1eb7t R2C \uf03d 2 \uf028n \uf02d1\uf029 1 \uf03d 2 \uf028p \uf02d1\uf029 p L n","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 1) \uf0ef\uf0ecUL max \uf0db \uf0ed\uf0ee\uf0ecZZCL \uf03dn \uf03d n U \uf0ef \uf0db \uf0ed\uf0ec\uf0eeZZCL \uf03d 1 \uf0de \uf077L \uf03d LC 1 \uf02d n\uf02d2 \uf0ed \uf03d1 \uf0ee\uf0ef\uf0ef U C max \uf03d n \uf0de \uf077C 1 v\u00e0 UL max \uf03d UCmax \uf03d nLC \uf0ec URL max \uf0db \uf0ec ZL \uf03dp \uf0db \uf077RL \uf03d p U \uf0ef \uf0ed ZC \uf03d1 LC 1 \uf02d p\uf02d2 \uf0ef \uf0ee 2) \uf0ed v\u00e0 URL max \uf03d URC max \uf03d \uf0ec ZL \uf03d1 1 \uf0ef URC max \uf0db \uf0ed ZC \uf03dp \uf0db \uf077\uf03d pLC \uf0ee\uf0ef \uf0ee V\u1edbi c\u00e1c gi\u00e1 tr\u1ecb (R, L, C) nh\u1ea5t \u0111\u1ecbnh s\u1ebd t\u00ecm \u0111\u01b0\u1ee3c c\u00e1c gi\u00e1 tr\u1ecb n > 1 v\u00e0 p > 1. Kinh nghi\u1ec7m: \u2022 Khi \u03c9 thay \u0111\u1ed5i li\u00ean quan \u0111\u1ebfn ULmax,UCmax, URlmax v\u00e0 UCmax th\u00ec gi\u00e1 tr\u1ecb c\u1ed1t l\u00f5i n\u1eb1m \u1edf gi\u00e1 tr\u1ecb c\u1ee7a bi\u1ec3u th\u1ee9c R2C\/L Khi \u0111\u00e3 t\u00ecm ra \u0111\u01b0\u1ee3c gi\u00e1 tr\u1ecb \u0111\u00f3 th\u00ec s\u1ebd t\u00ecm \u0111\u01b0\u1ee3c n v\u00e0 p r\u1ed3i t\u00ecm \u0111\u01b0\u1ee3c h\u1ebft c\u00e1c \u0111\u1ea1i l\u01b0\u1ee3ng kh\u00e1c. \u2022 V\u1edbi b\u00e0i to\u00e1n \u1edf m\u1ee9c v\u1eadn d\u1ee5ng cao th\u01b0\u1eddng l\u00e0 s\u1ef1 ch\u1ed3ng ch\u1eadp c\u1ee7a nhi\u1ec1u b\u00e0i to\u00e1n kh\u00f3. Nhi\u1ec7m v\u1ee5 c\u1ee7a ch\u00fang ta l\u00e0 c\u1eaft l\u1edbp c\u00e1c b\u00e0i to\u00e1n \u0111\u1ec3 t\u00ecm ra gi\u00e1 tr\u1ecb c\u1ed1t l\u00f5i. * V\u1edbi d\u1ea1ng b\u00e0i to\u00e1n li\u00ean quan \u0111\u1ebfn m\u1ed9t h\u1ec7 th\u1ee9c li\u00ean h\u1ec7 gi\u1eefa c\u00e1c t\u1ea7n s\u1ed1 th\u00ec suy ngh\u0129 \u0111\u1ea7u ti\u00ean l\u00e0 bi\u1ec3u di\u1ec5n c\u00e1c t\u1ea7n s\u1ed1 theo R, L, C r\u1ed3i thay v\u00e0o h\u1ec7 th\u1ee9c li\u00ean h\u1ec7 \u0111\u1ec3 chuy\u1ec3n v\u1ec1 c\u1ee5m bi\u1ebfn R2C\/L. Ch\u1eb3ng h\u1ea1n: \uf0ef\uf0ec\uf077 \uf03d \uf0771 \uf0de tan \uf06aRC \uf03d \uf02d1 \/ \uf0771C \uf0de \uf0771 \uf03d RC \uf02d1 R tan \uf06aRC \uf0ef \uf0f62 \uf0f62 \uf0ef \uf0772 L R tan \uf06aRL \uf0be\uf0be\uf0be\uf0be\uf0be\uf0be\uf0be\uf0ae RLCa\uf0e6\uf0772\uf0f7\uf0f7\uf0f8\uf02b b\uf0e8\uf0e7\uf0e7\uf0e6 \uf0772 \uf0f7\uf0f7\uf0f8 \uf02bc\uf03d0 2 \uf0ed\uf077 R L \uf0e8\uf0e7\uf0e7 \uf0773 \uf0771 \uf03d \uf0772 \uf0de tan \uf06aRL \uf03d \uf0de \uf0772 \uf03d \uf03d? \uf0ef 1 \uf0ef\uf0ef\uf077 \uf03d \uf0773 \uf0de Mach cong huong \uf0db \uf0773 \uf03d LC \uf0ee C\u00e2u 180. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d 50 42 cos \uf028\uf077t \uf02b \uf070 \/ 6\uf029 (V) (\u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo \u0111\u00fang th\u1ee9 t\u1ef1 g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi \uf077 \uf03d \uf0771 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean \u0111o\u1ea1n m\u1ea1ch RC l\u1ec7ch pha 45\u00b0 so v\u1edbi d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch. Khi \uf077 \uf03d \uf0772 th\u00ec \u0111i\u1ec7n \u00e1p h\u00ean \u0111o\u1ea1n m\u1ea1ch RL l\u1ec7ch pha 60\u00b0 so v\u1edbi d\u00f2ng \u0111i\u1ec7n. Khi \uf077 \uf03d \uf0773 th\u00ec m\u1ea1ch c\u1ed9ng h\u01b0\u1eddng. Bi\u1ebft \uf0283\uf0772 \/ \uf0773 \uf0292 \uf02d \uf0285\uf0772 \/ \uf0771 \uf0292 \uf02b 75, 6 \uf03d 0 . Khi \u03c9 thay \u0111\u1ed5i th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L \u0111\u1ea1t gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i l\u00e0 A. 100 3 V. B. 300V. C. 250V. D. 50 6V . H\u01b0\u1edbng d\u1eabn \uf0ec \uf02d1 1 \uf0ef\uf0ef \uf0771CR \uf0de \uf0771 \uf03d CR \uf028 \uf028 \uf029 \uf029* Theo \u0111\u1ec1 b\u00e0i: tan \uf06aRC \uf03d \uf03d tan \uf02d450 \uf03d \uf0ed \uf0772L R3 \uf0be\uf028\uf0be3\uf0772\uf0be\/\uf0773 \uf0be\uf0292 \uf02d\uf028\uf0be5\uf0772 \uf0be1\/\uf0771 \uf029\uf0be2 \uf02b7\uf0be5,6\uf03d\uf0be0\uf0ae \uf0ef R \uf0de \uf0772 \uf03d L \uf0773 \uf03d LC \uf0ee\uf0ef tan \uf06aRL \uf03d tan 600 27 R2C \uf02d 75 \uf0e6 R2C \uf0f62 \uf02b 75, 6 \uf03d 0 \uf0de R2C \uf03d 0, 6 \uf0be\uf0beR22LC\uf0be\uf03d1\uf02d\uf0be1n \uf0ae n \uf03d 2, 5 L \uf0e7 L \uf0f7 2L \uf0e8 \uf0f8 * Theo BHD4: UL max \uf03d U \uf03d 250\uf028V\uf029 \uf0de Ch\u1ecdn C. 1 \uf02d n\uf02d2 C\u00e2u 181. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d 50 42 cos \uf028\uf077t \uf02b \uf070 \/ 6\uf029 (V) (\u03c9 thay \u0111\u1ed5i \u0111\u01b0\u1ee3c) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo \u0111\u00fang th\u1ee9 t\u1ef1 g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C. Khi \uf077 \uf03d \uf0771 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean \u0111o\u1ea1n m\u1ea1ch RC l\u1ec7ch pha 135\u00b0 so v\u1edbi d\u00f2ng \u0111i\u1ec7n trong m\u1ea1ch. Khi \uf077 \uf03d \uf0772 th\u00ec \u0111i\u1ec7n \u00e1p tr\u00ean \u0111o\u1ea1n m\u1ea1ch RL l\u1ec7ch pha 135\u00b0 so v\u1edbi d\u00f2ng \u0111i\u1ec7n. Khi \uf077 \uf03d \uf0773 th\u00ec m\u1ea1ch c\u1ed9ng h\u01b0\u1eddng. Bi\u1ebft \uf0282\uf0772 \/ \uf0773 \uf0292 \uf02d \uf028\uf0772 \/ \uf0771 \uf0292 \uf03d 3,84 . Khi \u03c9 thay \u0111\u1ed5i th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L \u0111\u1ea1t gi\u00e1 tr\u1ecb c\u1ef1c \u0111\u1ea1i l\u00e0 A. 100 3 V. B. 129V. C. 150V. D. 50 6V . H\u01b0\u1edbng d\u1eabn * T\u1eeb \u0111\u1ec1 b\u00e0i suy ra: \uf0772 L \uf03dR \uf03d 1 \uf0be\uf028\uf0be2\uf0772\uf0be\/\uf0773\uf0be\uf0292 \uf02d\uf028\uf0be\uf0772 \/\uf0be\uf0771 \uf0292\uf0be\uf03d3,8\uf0be4\uf0ae 4 R2C \uf0e6 R2C \uf0f62 \uf03d 3,84 \uf0771C L \uf02d\uf0e7 \uf0f7 \uf0e8 L \uf0f8 \uf0de R2C \uf03d 0, 8 \uf0be\uf0beR22LC\uf0be\uf03d1\uf02d\uf0be1n \uf0ae n \uf03d 5 2L * Theo BHD4: ULmax \uf03d U \uf03d 50 6 \uf028V\uf029 \uf0de Ch\u1ecdn D. 1 \uf02d n\uf02d2","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 C\u00e2u 182. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos \uf077t (V) (U kh\u00f4ng \u0111\u1ed5i, \u03c9 thay \u0111\u1ed5i) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp theo th\u1ee9 t\u1ef1 g\u1ed3m \u0111i\u1ec7n tr\u1edf R, cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C sao cho L = R2C. Khi \uf077 \uf03d \uf0771 ho\u1eb7c \uf077 \uf03d \uf0772 th\u00ec h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t c\u1ee7a m\u1ea1ch AB \u0111\u1ec1u b\u1eb1ng k. Khi \uf077 \uf03d \uf0773 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L c\u1ef1c \u0111\u1ea1i. Bi\u1ebft \uf0771 \uf02b \uf0772 \uf02b 3\uf0773 . Gi\u00e1 tr\u1ecb k g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 0,35. B. 0,56. C. 0,45. D. 0,86. H\u01b0\u1edbng d\u1eabn * Theo BHD4: 1\uf02d 1 \uf03d R2C \uf03d 1 \uf0de n \uf03d 2 \uf0de \uf0773 \uf03d \uf077L \uf03d n \uf03d 2\uf0770 n 2L 2 LC \uf0de \uf0771 \uf03d \uf0772 \uf02b 6\uf0770 \uf0be\uf077\uf0be1\uf0772\uf0be\uf03d L1C\uf0be\uf03d\uf077\uf0be02 \uf0ae \uf0771 \uf03d 2,806\uf0770 \uf0771L \uf02d 1 \uf0771 \uf02d 1 \uf0771 \uf02d \uf07702 2, 806\uf0770 \uf02d \uf07702 \uf0771C \uf0771LC \uf0771 2, 806\uf0770 * T\u1eeb tan \uf06a1 \uf03d \uf03d \uf03d \uf03d R R2C 1 R2C 1\uf0770 L \uf0770 L LC \uf0de cos \uf06a1 \uf03d 0,38 \uf0de Ch\u1ecdn A. C\u00e2u 183. \u0110\u0103t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos 2\uf070ft (V) v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C v\u1edbi L = CR2. M\u1ea1ch c\u00f3 c\u00f9ng h\u1ec7 s\u1ed1 c\u00f4ng su\u1ea5t cos\u03c6 v\u1edbi hai gi\u00e1 tr\u1ecb t\u1ea7n s\u1ed1 f1 v\u00e0 f2. Khi t\u1ea7n s\u1ed1 f3 th\u00ec \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean L c\u1ef1c \u0111\u1ea1i. N\u1ebfu f1= f2 + f3 2 th\u00ec cos\u03c6 g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 0,56. B. 0,35. C. 0,86. D. 0,45. H\u01b0\u1edbng d\u1eabn C\u00e1ch 1: (Mang t\u00ednh t\u01b0 duy ti\u1ec3u x\u1ea3o kh\u00f4ng c\u00f3 kh\u1ea3 n\u0103ng kh\u00e1i qu\u00e1t h\u00f3a b\u00e0i to\u00e1n) * T\u1eeb L \uf03d CR 2 \uf0de R 2 \uf03d ZLZC. * Khi ULmax theo BHD1 \uf0de ZC3 \uf03d Z\uf074 \uf03d ZL3ZC3 \uf02d R2 \uf0de ZL3 \uf03d 2ZC3 \uf03dR 2 2 * V\u00ec c\u00f9ng cos\u03c6 n\u00ean c\u00f9ng Z \uf0de \uf0771\uf0772 \uf03d 1 \uf0de ZC2 \uf03d ZL1 LC \uf0de cos \uf06a \uf03d R \uf03d R \uf03d R \uf03d 0, 45 \uf028 \uf029R 2 \uf02b ZL2 \uf02d ZC2 2 \uf028 \uf029R2 \uf02b ZL2 \uf02d ZL1 2 \uf028 \uf029R2 \uf02b 2ZL3 2 C\u00e1ch 2: (C\u00f3 kh\u1ea3 n\u0103ng kh\u00e1i qu\u00e1t h\u00f3a b\u00e0i to\u00e1n) R2C 1 1 \uf0ec ZC \uf03d 1; ZL \uf03dn \uf03d 2; R \uf03d 2n \uf02d 2 \uf03d 2 2L 2 n \uf0ef \uf03d n \uf03d * Theo NHD4: \uf03d \uf03d1\uf02d \uf0de n \uf03d 2 \uf0de \uf0ed LC 2 LC \uf0ef\uf0773 \uf0ee * V\u00ec c\u00f9ng cos\u03c6 n\u00ean c\u00f9ng Z \uf0de \uf0771\uf0772 \uf03d 1 \uf03d \uf07732 LC 2 \uf0ecR \uf03d 2 \uf0ef \uf0ef ZC R \uf0be\uf077\uf0be1 \uf03d\uf077\uf0be2 \uf02b\uf077\uf0be3 2\uf0be\uf0ae o2 \uf03d 1, 707\uf0773 \uf0de \uf0ed ZC 2 \uf03d 1, 707 \uf03d 0, 586 \uf0de cos \uf06a \uf03d Z \uf03d 0, 45 \uf0ef \uf0ee\uf0efZL2 \uf03d 1, 707ZL Kh\u00e1i qu\u00e1t d\u1ea1ng to\u00e1n: M\u1ea1ch RLC c\u00f3 \u03c9 thay \u0111\u1ed5i v\u1edbi L = aR2C (a > 0,5) khi \u03c91 ho\u1eb7c \u03c92 th\u00ec m\u1ea1ch c\u00f3 c\u00f9ng b (v\u1edbi b = Z, cos\u03c6, I, P,UR). Khi \u03c93 th\u00ec ULmax ho\u1eb7c UCmax ho\u1eb7c URlmax ho\u1eb7c URlmax ho\u1eb7c URcmax. Bi\u1ebft s\u1ef1 ph\u1ee5 thu\u1ed9c f \uf028\uf0771 , \uf0772 , \uf0773 \uf03d 0 \uf029 H\u00e3y t\u00ednh b. C\u00e2u 184. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos 2\uf070ft \uf028V\uf029 v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C v\u1edbi L = CR2. M\u1ea1ch ti\u00eau th\u1ee5 c\u00f9ng c\u00f4ng su\u1ea5t P1 v\u1edbi hai gi\u00e1 tr\u1ecb t\u1ea7n s\u1ed1 f1 v\u00e0 f2. M\u1ea1ch ti\u00eau th\u1ee5 c\u00f4ng su\u1ea5t P4 khi t\u1ea7n s\u1ed1 f4 v\u00e0 l\u00fac n\u00e0y \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean cu\u1ed9n c\u1ea3m c\u1ef1c \u0111\u1ea1i. N\u1ebfu f1 + f2 = f3 12 th\u00ec bi\u1ec3u th\u1ee9c (P3\/P1 + P4\/P1) g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 4 B. 5 C. 3 D. 6 H\u01b0\u1edbng d\u1eabn * Theo b\u00e0i ra: \uf0771\uf0772 \uf03d 1 \uf03d \uf07702 . Gi\u1ea3 s\u1eed \uf0771 \uf03c \uf0772 LC","TR\u01af\u01a0NG TH\u1eca NGUY\u00caN \u2013 \u0110I\u1ec6N XOAY CHI\u1ec0U M\u1edaI L\u1ea0 KH\u00d3 \uf0ec \uf0ef \uf0ef ZL \uf03d 1; ZC \uf03d n \uf03d 2; R \uf03d 2n \uf02d 2 \uf03d 2 2 2 * Theo BHD 4: R2C \uf03d 1 \uf03d 1\uf02d 1 \uf0de n \uf03d 2 \uf0de \uf0ef\uf0edcos2 \uf06a3 \uf03d cos2 2L 2 n \uf06a4 \uf03d n \uf02b1 \uf03d3 \uf0ef \uf0ee\uf0ef\uf0ef\uf06a3 \uf0770 \uf0770 \uf03d n \uf03d 2 \uf0de \uf0771 \uf02b \uf0772 \uf03d \uf0770 6 \uf0ec \uf0efR \uf03d 2 6\uf02d 2 \uf0ef\uf0ef 1 2 \uf0770 \uf03d \uf0ed 3 \uf028 \uf029\uf0de \uf0771 \uf03d ZL cos2 cos2 3 \uf02d1 \uf077C \uf0de \uf03d 3 \uf02d1 \uf0de \uf06a1 \uf03d \uf06a2 \uf03d 2 \uf0ef ZC \uf0ef \uf0ee\uf0ef \uf03d 3 \uf02d1 P3 \uf02b P4 \uf03d cos2 \uf06a3 \uf02b cos2 \uf06a4 \uf03d4\uf0de Ch\u1ecdn A. P1 P1 cos2 \uf06a1 cos2 \uf06a1 C\u00e2u 185. \u0110\u1eb7t \u0111i\u1ec7n \u00e1p u \uf03d U 2 cos 2\uf070ft \uf028V\uf029 v\u00e0o hai \u0111\u1ea7u \u0111o\u1ea1n m\u1ea1ch AB m\u1eafc n\u1ed1i ti\u1ebfp g\u1ed3m cu\u1ed9n c\u1ea3m thu\u1ea7n c\u00f3 \u0111\u1ed9 t\u1ef1 c\u1ea3m L, \u0111i\u1ec7n tr\u1edf thu\u1ea7n R v\u00e0 t\u1ee5 \u0111i\u1ec7n c\u00f3 \u0111i\u1ec7n dung C v\u1edbi L = CR2. M\u1ea1ch ti\u00eau th\u1ee5 c\u00f9ng c\u00f4ng su\u1ea5t P0 v\u1edbi hai gi\u00e1 tr\u1ecb t\u1ea7n s\u1ed1 f1 v\u00e0 f2. M\u1ea1ch ti\u00eau th\u1ee5 c\u00f4ng su\u1ea5t P khi t\u1ea7n s\u1ed1 f3 v\u00e0 l\u00fac n\u00e0y \u0111i\u1ec7n \u00e1p hi\u1ec7u d\u1ee5ng tr\u00ean cu\u1ed9n c\u1ea3m c\u1ef1c \u0111\u1ea1i. N\u1ebfu (f1\/f3 + f2\/f3)2 th\u00ec bi\u1ec3u th\u1ee9c P0\/P g\u1ea7n gi\u00e1 tr\u1ecb n\u00e0o nh\u1ea5t sau \u0111\u00e2y? A. 0,22 B. 0,45 C. 0,57 D. 0,66 H\u01b0\u1edbng d\u1eabn * V\u00ec c\u00f3 c\u00f9ng P n\u00ean \uf0771\uf0772 \uf03d 1 \uf03d \uf07702 ; Gi\u1ea3 s\u1eed \uf0771 \uf03e \uf0772. LC R2C 1 \uf0ec ZL \uf03d 1; ZC \uf03d n \uf03d 2; R \uf03d 2n \uf02d 2 \uf03d 2 2L n \uf0ef 2\uf0773 * Theo BHD4: \uf03d1\uf02d \uf0de n \uf03d 2 \uf0de \uf0ed \uf0770 \uf0770 \uf0ef\uf0773 \uf03d n \uf03d 2 \uf0de \uf0770 \uf03d \uf0ee \uf0ec\uf0efZL' \uf03d 0, 5 2ZL \uf03d 0, 5 2 \uf0ef\uf0edZ'C \uf03d ZC \uf03d 2 2 \uf0be\uf0be\uf0be\uf0be\uf0be\uf0be\uf0ae \uf077\uf0771\uf0772 \uf03d\uf07702 \uf03d2\uf07732 1 \uf03d 0, 5 2\uf077C \uf0de \uf0ee \uf0771 \uf02b\uf0772 \uf03d2,5 2\uf0773 0,5 2 P0 \uf0e6 Z3 \uf0f62 2 \uf02b \uf0281\uf02d 2\uf0292 6 0, 46 Ch\u1ecdn B. P \uf0e7 Z0 \uf0f7 13 \uf0e8 \uf0f8 0,5 2 \uf02d 2 \uf028 \uf029\uf0de \uf03d \uf03d 2 \uf03d \uf03d \uf0de 2\uf02b 2"]