on tap ly thuyet mach 5384

8/22/2019 On Tap Ly Thuyet Mach 5384

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L thuyt mch Daniel F.SHanoi University of Technolo

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KHI NIM C BN

I/ Ngun c lp:

1. Ngun p:P = U.I < 0L tng: Ri = 0Khng l tng:

Cng thc phn p:

2. Ngun dng:L tng: Khng l tng:

Cng thc phn dng:

II/ Ngun ph thuc:

1. Ngun p ph thuc vo p (AA)

= 2. Ngun p ph thuc vo dng (AD)

= 3. Ngun dng ph thuc vo p (DA)

= 4. Ngun dng ph thuc vo dng (DD)

=

III/ Cc thng s r, L, C, M1. in tr:

2. in cm:

3. in dung:

4. H cm: Du (+) khi 2 dng cng chy vo (hoc ra) u cntn (*). u cng tn th hin chiu qun dy.

A

B


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L thuyt mch Daniel F.SHanoi University of Technology

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IV. Cc thng s dng phc:Sut in ng

Nu tc ng l cos: Nu tc ng l sin:

nh lut Ohm

Trkhng

Dn np

in tr

in cm

in dung

H cm


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CC PHNG PHP PHN TCH MCH INI/ nh lut Kirchoff I: Tng i s cc dng ti 1 nt bng 0.

- Ly du (+) khi dng chy ra khi nt- Ly du (-) khi dng chy vo nt

II/ inh lut Kirchoff II: Tng i s cc in p trn cc nhnh trong 1 vng kn bng 0.III/ Phng php in p nt:

- C s: nh lut Kirchoff I

- n strung gian: in p nt- n s cui cng: Dng in trn cc nhnh Dng cng thc bin i nt tnh dng in cc nhnh tin p cc nt.

Cch lm:- Chn nt gc bng 0V- Vit phng trnh cho cc nt, vi n sl in th cc nt:

V tri: Ly in p nt ang xt nhn vi tng dn np thuc nt , ri tri cc tch gia in nt ln cn vi dn np chung ca nt ln cn v nt ang xt.

V phi: Tng i s cc ngun dng c bin i t cc ngun p c ni vo nt ang xt.Du (+) khi chiu ca ngun dng chvo nt ang xt.Du (-) khi chiu ca ngun dng i ra khi nt ang xt.

- Gii hcc phng trnh va vit.- Dng cc cng thc bin i nt tm dng in trn cc nhnh.

V d:- Chn - Vit phng trnh cc nt:

Nt A: Nt B: . Nt C:

.

.

.

Nt D: . . Ta c hphng trnh:

( ) (

)

(

)

- Gii ra

- Cng thc bin i nt:


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IV/ Phng php dng in vng:- Cs: inh lut Kirchoff II- n s trung gian: - n s cui cng: Dng cng thc bin i vng tnh dng in cc nhnh tcc dng in vng

V d:

- Vit phng trnh cho cc vng:Vng 1: Vng 2: Vng 3: Ch ti du ca

- Gii ra - Dng cng thc bin i vng:

V/ Nguyn l xp chng:Mch in c cha nhiu ngun tc ng, c th coi do tng ngun tc ng (cc ngun khc ngn

mch), ri cng cc kt qu li.


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VI/ nh l ngun tng ng:

Mch in c cha nhiu ngun tc ng c ni vi phn cn li ti cp im AB, c th thay th bngngun sut in ng bng .

- Ct nhnh c hi ra khi mch ti cp im AB- Tnh bng cc phng php hc- Tnh - Vs tng ng, lp nhnh b ct vo s v tnh I

* Ch : Cch tnh

c 2 nhnh song song:

Du (-) khi 2 dng cng chy vo (hoc ra) u cng tn

VII/ Bin i Laplace:

1. Bin i R, L, C trong min pin tr

u(t) = r.i(t) U(p) = r.I(p)in cm

in dung


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2. Bin i Laplace ca mt s hm sc bn:Hm gc Hm nh Hm gc Hm nh

* 1

3. Bin i Laplace ngc - Heaviside: - Nghim ca l im 0 ca , c th nm bt c ch no trn mt phng phc.- Nghim ca l im cc ca , ch c th nm na mt phng tri v trn trc o.a) c nghim n

b) c nghim bi ( c) c cp nghim phc lin hip


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MCH QU rC, rL, rLCNgun sut in ng bin thin theo thi gian, p ng ra ca mch bao gicng c dng: Trong :

l ch xc lp l chqu

l hng s thi gian

l in trtng ng ca ton mch (lc sau) nhn t c

im L (hoc C), vi iu kin ngn mch Eng, hmch Ing.Di tc ng 1 chiu, C coi nh hmch, L coi nh ngn mch.Cc bc gii:

kha Ktrng thi ban u, xc nh cc iu kin u ca bi ton: . V li m hnh trong min p. Chuyn K n v tr mi, vit phng trnh p ng ca mch trong min p. Gii phng trnh. Dng Heaviside chuyn F(p) f(t). Kim tra li bng cng thc trn.

V d 1: Cho mch in nh hnh v, lc u kha K m. . ng kha K, tm Khi K m, V li mch trong min p ng kha K, ta c phng trnh in p nt: *

*

Kim tra li:


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V d 2: Cho mch in nh hnh v, lc u kha K ng. . Mkha K, tm Khi K ng:

Khi K m: Theo nh lut Kirchoff II:

* Kim tra:

V d 3: Cho mch in nh hnh v. Tm i(t) = ?p dng nh lut Kirchoff II:

a/


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b/ e (t) = 0

V d 4: Cho mch in nh hnh v. p dng nh lut Kirchoff II: a/

*

*


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b/


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MCH DAO NG NI. Mch dao ng n ni tip:

* *

a/ Dng in cng bc: b/ Dng in qu :

Lng suy gim loga tnhin ca dao ng tt dn:

.

Thi gian tt ca dng qu : in trti hn :

Khi


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c/ Dng in tng hp:

Khi = 0 th

Di thng l di tn s m


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II. Mch song songi ngu vi mch ni tip: Cc phn ti ngu:

Xy dng mch i ngu: Ly 1 im A trong mch v 1 im B ngoi

mch.

Ni AB, mi ln ni ct qua mt phn t (xemhnh minh ha)

ngha: Nu c 2 mch i ngu th tnh cht mch nyc thc suy ra mt cch i ngu t mch kia.

Ni tip Song song

1. Trkhng

1. Dn np

2. Dn np

| |

2. Trkhng

| |

3. Phm cht ti

3. Phm cht ti

4. Di thng 4. Di thng

5. lch tn s

5. lch tn s


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6. Dng in

7. in p trn r

8. in p trn L

9. in p trn C

6. in p

7. Dng trn R

8. Dng trn C 9. Dng trn L

10. in p v dng in ti

}

10. in p v dng in ti

} in trtng ng ca mch dao ng n song song (thc t)

V d 1: Cho mch in nh hnh v. a/ Tnh b/ Cho Em = 20V, f = 400kHz. Tnh Um,

?

Gii: a/ Bin i mch nh hnh v trn


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R= Ri // R = 5k R// b/ Vi Em = 20V

V d 2: Cho mch in nh hnh v.

a/ Cho Ingm = 5mA. Tnh R, C?b/ Cho Q = 10. Tnh c/ Tnh Um vi f = 200kHz.

Gii: a/ Ti f = 0 th b/

c/


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TH BODENguyn tc chung ca th Bode l vp ng tn s ca mch (bin v pha) bng cch tng hp trctip cc c tuyn tn s thnh phn ng vi cc im 0 v im cc ca H(p).

c tuyn bin : c tuyn pha:

Cc c tuyn ny c thc hin trn thang t llogarithmic i vi , k hiu l trc [Decade]

nh v tr ca trn trc : a v dng n quyt nh Decade, nmg trong Decade (n; n+1) m quyt nh v tr ca trong Decade , m = 2 th nm ti 1/3 Decade, m = 5 th nm

ti 2/3 Decade

V d: nm trong Decade (3; 4) nm ti v tr 1/3 Decade

th Bode ca mt s hm s(xt im 0):1. 2.

Nu th ng cho 20dB/Dkhng i qua gc ta m i qua Nu th ng cho c dc 40dB/D v i qua 3.

||

[ ]


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Nu th thbin khng thay inhng thpha i xng qua trc honhNu th dc ca thbin l 40dB/D.4. C cp nghim phc lin hip. Nu cp nghimphc ny nm na mt phng tri th:

*

Nu cp nghim phc nm na mtphng phi th thbin khng i,nhng th pha ly i xng qua trchonh.


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5.

arg * Mt s ch :1. a thc bc nht:

*2. a thc bc hai: * * *

th Bode ca im cc (nghim mu s) i xng vi th ca im 0 qua trc honh.V d 1:


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V d 2:


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(1)


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MNG BN CC

I/ Hphng trnh trkhng hmch:

i vi s hnh T:

II/ Hphng trnh dn np ngn mch:


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i vi s hnh :

Bn cc i xng: Khng phn bit c ca 1 v ca 2. Khi :

V d:Xt s tng ng hnh X c mng 4 cc i xng: | Theo Kirchoff II:

|

III/ Hphng trnh c tnh truyn t:


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a = detA = -1

i vi s hnh G:

* i vi s hnh G ngc:

IV/ Hphng trnh c tnh truyn t ngc:

b = det B = -1

V/ Hphng trnh c tnh hn hp:


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VI/ Hphng trnhc tnh hn hp ngc:

Lin h gia cc thng s ca mng 4 cc:

c im ca bng:+ Trong mt hnh ch nht bt k ca bng, tch cc thng s trn ng cho bng nhau.VD: -h21.z12 = h12.z21


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VII/ nh l Batlet dng cho 4 cc i xng:Mi 4 cc i xng u c thc thay th bng s tng ng hnh X, vi cc phn t

c xc nh nh sau:+ Bi 4 cc i xng thnh 2 na bng nhau

+ - Dy dn thngb ct c ngn mch.- Dy dn cho b ct c hmch.

+ - Dy dn thngb ct c hmch.- Dy dn cho b ct c ngn mch.V d:

VIII/ K thut tnh ton - Chun ha gi tr:

S dng cho 4 i lng: R, L, C, + Chn 2 trong 4 i lng trn lm chun, ri tnh 2 i lng cn li theo 2 cng thc trn.+ Tnh ton cc gi trtng i, gii bi ton bng cc gi trtng i .+ i gi trtng i thnh gi tr tuyt i (nhn vi )V d:

Chn 2 gi tr chun: Tnh 2 gi tr cn li:

Xc nh cc gi trtng i:


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Tnh *

*

IX/ Ni ghp cc 4 cc:1. Ni tipNi tip:

2. Song songSong song:

3. Ni tipSong song:


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4. Song songNi tip:

5. Dy chuyn:

(1) (2)

(3)

(4)

(5)

ng dng: Bn cc phc tp c thc tch thnh cc bn cc n gin. Cc bn cc n ginny ni vi nhau theo cc cch trn.

Cc loi 4 cc n gin:Hnh T, hnh , hnh I, hnh G, hnh G ngc, hnh =, Transistor


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V d: Cho mng 4 cc nh hnh v, xc nh cc thng s dn np ngn mch v thng s truyn t ca mng. Cho Gii:


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X/ Hm truyn t:

XI/ H s truyn t:

Vi 4 cc i xng:


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XII/ Cc thng s sng (Thm ch s 0 vo thng sthng):


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Xc nh thng s sng:

Ch : Vi 4 cc i xng c phi hp trkhng 2 ca:Nu l 4 cc i xng vi s tng ng mch cu:

V d 1:


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V d 3:a.


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XIII/ Bn cc tuyn tnh khng tng h:1. Hphng trnh trkhng hmch:

2. Hphng trnh dn np ngn mch:

3. Hphng trnh c tnh hn hp:


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4. V d v bn cc khng tng h:a. Girator:

K hiu ca Girator nh hnh v:Hphng trnh trkhng:

, + Cc thng smang ngc du vi iu kin tng h Girator l bn cc phn tng h. Cng sut tc thi p(t) = 0, Girator l phn tqun tnh, khng tng hnhng thng.Quan h gi trkhng vo ca ny vi trkhng ti ca kia:

nu r l s thc th 2 phn t trkhng i ngu.

b. Mch bin i trkhng m (NIC):


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c. Transistor:


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d. Mch khuch i thut ton (Operational Amplifier)

Mch KTT l tng: Mch KTT khng l tng:


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V d 1: Xt mch khuch i thut ton nh hnh v:

V d 2: Mch cng v mch tr:

Mch cng:

Mch tr:


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V d 3: Xt mch khuch i thut ton:Xt nt 3: Xt nt 4: M T (2) (3)

a/ Mch lc thng thp

b/

Mch lc thng cao

c/ Mch lc thng di

Ba mch trn lKhu lc tch cc RC bc 2


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MCH LC TN SB lc cho 1 hay nhiu di tn hiu i qua (di thng), chn cc di tn s cn li (di chn).Tn sgia di thng v di chn l tn s ct (cutfreq)

Mt b lc phc tp c th chia thnh cc b lc n gin (hnh T, hnh )

iu kin di thng:


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I/ Mch lc loi K:

1. Mch lc thng thp:

2. Mch lc thng cao:

3. Mch lc thng di:


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4. Mch lc chn di:

II/ Trkhng sng cc b lc loi k:1. Mch lc thng thp:a/ Hnh T:

Trong di chn: mang tnh in cm

Trong di thng: mang tnh in tr

b/ Hnh :


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Trong di chn: mang tnh in dung Trong di thng: mang tnh in tr

2. Mch lc thng cao:a. Hnh T:

Trong di chn: mang tnh in dungTrong di thng: mang tnh in tr

b/ Hnh :

Trong di chn: mang tnh in cmTrong di thng: mang tnh in tr

3. Mch lc thng di:


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4. Mch lc chn di:

III/ Suy gim sng, dch pha sng ca cc b lc loi k: Trong di thng:

Trong di chn:

1. Mch lc thng thp: 3. Mch lc chn di:

2. Mch lc thng cao: 4. Mch lc chn di:


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IV/ Mch lc loi M:

1. Xy dng b lc loi m:a/ Chuyn ni tip tTk sang Tm:

+ Gi li 1 phn + Chuyn phn cn li mt cch ni tip xung nhnh song song to thnh

sao cho

b/ Chuyn song song tk sang m:+ Gi li 1 phn + Chuyn phn cn li mt cch song song ln nhnh ni tip to thnh sao cho

2. Cc loi b lc loi m:a/ Lc thng thp:


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b/ Lc thng cao:

{

c/ Lc thng di:

d/ Lc chn di:


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3. B phi hp trkhng:

Phi hp trkhng vi Ri = Rt = const

Tnh

:

ph thc vo m ( 0 < m < 1), vi m = 0,6 th trkhngsng bng phng trong sut di thng.


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Tnh :

ph thc vo m ( 0 < m < 1), vi m = 0,6 th trkhng sngbng phng trong sut di thng.

4. Suy gim sng:

a/ Lc thng thp:

c/ Lc thng di:

*

b/ Lc thng cao:

d/ Lc ch n d i:

*


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B lc loi K, cng i su vo di chn, . Tuy nhin chm. B lc loi M, cng i su vo di chn, cng gim. Tuy nhin nhanh ti .

V. Thit k b lc y :


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V d: Thit k lc thng thp y c Phi hp trkhng gia ngun v ti c v c suy gim sng cng i su vo di chn cng tin ti Gii:1. Lc K:

T (1) (2) suy ra: 2. Lc M:


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3. Phi hp trkhng: (thay m = 0,6)


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MC LCTrang

Khi nim c bn 1I. Ngun c lp 1II. Ngun ph thuc 1III. Cc thng s r, L, C, M 1

IV. Cc thng s dng phc 2

Cc phng php phn tch mch in 3I. nh lut Kirchoff I 3II. nh lut Kirchoff II 3III. Phng php in p nt 3IV. Phng php dng in vng 4V. Nguyn l xp chng 4VI. nh l ngu n tng ng 5VII. Bin i Laplace 5

Mch qu rC, rL, rLC 7Mch dao ng n 11

I. Mch dao ng n n i ti p 11II. Mch song songi ngu vi mch ni tip 13

th Bode 16

Mng bn cc 22I. Hphng trnh trkhng hmch 22II. Hphng trnh dn np ngn mch 22

III. Hphng trnh c tnh truyn t 23IV. Hphng trnh c tnh truyn t ngc 24V. Hphng trnh c tnh hn hp 24VI. Hphng trnh c tnh hn hp ngc 25VII. nh l Batlet dng cho 4 cc i xng 26VIII. K thut tnh tonChun ha gi tr 26IX. Ni ghp cc bn cc 27X. Hm truyn t 30XI. H s truyn t 30XII. Cc thng s sng 31XIII. Bn cc tuyn tnh khng tng h 34

Mch lc tn s 40I. Mch lc loi K 41II. Trkhng sng ca cc b lc loai K 42III. Suy gim sng, dch pha sng ca cc b lc loi K 44

on tap ly thuyet mach 5384

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