Bai Thuc Hanh Mach Tuong Tu of Tu

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Bi m u :

Gii Thiu Mt S Linh Kin V Cch o

I.Mc ch : - Sinh vin lm vic trong phng my, s dng thnh tho phn mm v bit c tnh cht ca cc linh kin khi ghp vo mch, kho st kim nghim cc mch in t c hc trong phn mch tng t nh: kho st BJT, FET, ng dng OpAmp, dao ng sin tn s thp v dao ng khng sin.Qua cho ta thy c s khc bit gia thc hnh v l thuyt, kh nng t nhn xt da trn cc hin tng v quan st gin xung. - Gip ta xc nh chn ca cc loi: bin tr,diode,transistor. - o th cc loi linh kin trn bit linh kin cn tt hay hng. - Sau y l mt s linh kin thng s dung trong mch v cch o n: 1. Khi ta o th vi diode , th c diot vn hot ng tt , mt s hot ng khng ng v qu thi gian s dng nhiu ln nn linh b hng. + Hnh v :

+ Chn k ang s dng c dng in i t que que en: Khi o th ta xc nh c chn di l cc dng(+) ng vi chn 1, v ngc li chn ngn l cc m(-). + Cch xc nh trn l cch xc nh chung cho mi loi diode nhng trn thi trng c rt nhiu loi diode mi loi diode c mt hnh dang khc nhau .V sau y l mt s hinh nh v diode:

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Diode pht quang (led )

diode zener

2. o transistor:(dy l cc m cn dy en l cc dng) - u tin gi s que chn 1, t que en ra 2 chn cn li, ta thy c 1 chn que en khng ln. Tng t ta que chn 2, tque en 2 chn cn li v ta thy mt chn que en khng ln. Tip tc que chn 3 , th que en 2 chn cn li khng ln. y khng phi l trnistor loi PNP Ta que en chn 1 , th que chn 2,3 khng ln. Tng t chn 2 cng vy. que en chn 3 , que chn 2,3 u ln, t ta c th xc nh chn 3 l cc B => y l transistor loi NPN. Hnh v :

S dng tr 100K , 1 u cm B(chn 3) gi s chn 1 l chn C, dy en vo cc C cho dy vo 2 chn th in tr rt ln (kim ng h ch gi tr ln), gi s chn 2 l cc C , cho dy en vo C , dy vo chn 1 ng h ch gi tr nh m khi ng h ch gi tr cng nh th phn cc thun iu chng t chn 2 l cc C , chn cn li l cc E.

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Php o th th 2 : PNP: ngc li vi transitor NPN (s dng dy th cho dy en) th cc cc t c th suy ra cc cc. -Hnh v:

Transistor PN i vi transitor PNP th cc B l cc m, cc C,E l cc dng. 3. o linh kin bin tr : M hnh : bin tr l linh kin th ng C 3 chn , trong c 1 chn di ng v 2 chn c nh gi l chn 1 v chn 2. Dng Ohm k o in tr t chn di ng ti 2 chn c nh ta c : S ln o Ln 1 Ln 2 Ln 3 -Hnh v: Chn 1 10k 2k 1k Chn 2 5k 5k 250k

Bin tr 4. o linh kin SCR : - Hnh v:

Linh kin SCR - Cch o:

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

SCR l linh kin c 3 chn G , A , K dng kch IG, i vo chn G, ra chn K. Chn G l que en, K l que th kim Ohm k ln. o G-K dng gii X10. o chn G-A, A-K c 2 u khng ln(2 chiu l o 2 que o) nu o khng ln th SCR b hng. 5. Gii thiu v Oscilloscope - Hnh v:

Oscilloscope - Cc nt iu khin ca Oscilloscope: + Nt iu khin Volt/DIV (s volt trn mt ) + Time/DIV (thi lng trn 1 ) + Position ln, xung + Position qua, li ( chnh dng sng hin th v tr nhn nht) + Thanh iu khin Vert mode (chn hiu th knh 1, knh 2, hay c 2) + Nt Triglevel (i khi dng sng b tri, ta chnh nt ny dng sng ng li) + Thanh iu khin AC-GND-DC II.Ni Dung: Mn hc ny nhm trang b cho sinh vin - Kin thc: + Nhn bit cc linh kin v cc mch khi thc hnh trn my. + Hiu tng tn hn v c s l thuyt mch tng t. - K nng: + S dng thnh tho phn mm Electronics workbench v kim nghim mch trn phn mm ny. + Thy r s khc bit gia l thuyt v khi thc hnh trn phn mm ny. III.Thc Hnh: Sau khi nm r c cc tnh cht v chn ca cc linh kin th sinh vin bt u vo rp mch.Trong mn thc tp mch tng t ny c th sinh vin phi lm 6 bi thc tp nh sau : 1. Chnh lu in th -Ngun cp in. 2. Phn cc v khuych i Transistor. 3. Khuych i cng sut. 4. Khuych i thut ton. 5. ng dng khuych i thut ton. 6. Mch dao ng. - Tt c cc bi thc tp ni trn c th hin kh r v c th nh sau :

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Bi 1: CHNH LU IN TH -NGUN CP IN I. Mc ch: 1. Kho st cc mch chnh lu v lc to ngun in DC. 2. Kho st cc mch n p dung Diode Zener v Transistor II. C s l thuyt: n li l thuyt v cc mch chnh lu v lc RC, n p dng Diode Zener v transistor. Mch n p chuyn i ngun xoay chiu sang mt chiu vi in th ra n nh trong mt khong cho php no . III. Bo co: 1.Mch chnh lu bn k v lc RC: a. Khi cha mc t: Lp mch nh hnh bn, vi: Ngun: 5V, tn s 1Khz. in tr: 100 Ohm. Hnh 1.1 Dng sng ca hnh 1.1

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Hnh 1.2: Dng sng ca hnh 1.1. b. Thay i chiu ca Diode, lp mch nh hnh bn di:

Hnh 1.3: Thay i chiu Diode Quan st dng sng ta thu c hnh bn di: sng ra sng vo

Hnh 1.4: Dng sng ca hnh 1.3Trang:6

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Nhn xt: Khi cha thay i chiu Diode: + bn k dng Diode c phn cc thun nn dn in. Dng in qua in tr R c tr s bin thin theo bn k dng ca in p li vo. + bn k m Diode phn cc nguc nn khng dn in, lc ny khng c dng in chy qua Diode + Kt qu dng in v in p trn ti ch xut hin bn k dng nn in p ra l in p mt chiu c dng sng nh hnh 1.2. Khi thay i chiu Diode: + bn k dng Diode phn cc ngc nn khng dn in, nn khng c dng chy qua Diode. + bn k m Diode phn cc thun nn dn in. Dng in qua in tr R c tr s bin thin theo bn k m ca in p li vo. + Dng in v in p trn ti ch xut hin bn k m, in p ra l in p mt chiu c dng sng nh hnh 1.4. Qua ta rt ra nhn xt: + Diode ch dn in khi c phn cc thun. + Diode c tc dng chuyn ngun xoay chiu thnh mt chiu. + Sng li ra c gn sng cao. Mc mt Volt k song song vi ti R ta o c gi tr ca R: - VR = 1.888 (V) :Khi cha thay i chiu Diode - VR = -1.891 (V) :Khi thay i chiu Diode c. Mc mt t C song song vi ti R, c gi tr 10 F: Lp mch nh hnh v:

Hnh 1.5: Mch chnh lu v lc RC khi mc thm t.Trang:7

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Mc mt Volt k song song vi ti R, ta o c in p hai u ti R: VR = 4.672 (V) Quan st dng sng ta c hnh bn di:

sng ng ra

Sng ng vo

Hnh 1.6: Dng sng ca hnh 1.5. Nhn xt: Khi mc thm t C, sng ra bng phng hn, t nhp nh hn so vi khi khng mc t. Sng ra t nhp nh hn l do: + bn k dng Diode dn in, dng in i qua t v ti Rin p tng, lc ny t np in. + bn k m Diode khng dn inin p gim t nh v khng, lc ny t phng in qua R b vo s gim in p ra theo thi giangim gn sng ca in p mt chiu trn ti.Trang:8

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Dng in qua ti c lin tc v gn sng li ra gim so vi khi khng mc t nh c tnh np x ca t. d. Gim in tr ti: xung cn 50 Ohm. Mc Volt k song song vi ti R, ta o c in p hai u ti R: VR = 3.847(V) Lp mch nh hnh 1.5, nhng gim in tr ti cn 50 Ohm, quan st dng sng ta c hnh nh bn di:

sng ng ra

sng ng vo

Hnh 1.7: Dng sng khi gim in tr ti xung 50. Nhn xt: Sng ra nhp nh hn so vi trng hp in tr ti R=100 Ohm, nhng t nhp nh hn so vi khi cha mc t. Do dng x ca t gim dn theo hm s m t I = VDC/R xung 0V. Dng x tnh theo cng thc: ic(t) =VDC t e R

in tr gim dng ti lnyu cu t x in nhiu hndng x ca t tng gn sng tng ln.Trang:9

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

T cc kt qu trn ta c nhn xt: + Diode c tc dng chuyn ngun in xoay chiu thnh mt chiu. +T in c tc dng lm sng ng ra bng phng hn, gi tr in dung ca t lc cng ln sng ra cng bng phng, gi tr ca in tr cng nh sng ra c gn sng cng cao v ngc li (trng hp c mc t). + Gi tr in p trn ti c th o bng Volt k. 2. Chnh lu ton k v lc RC : a.Mch chnh lu ton k dng 2 Diode: Lp mch nh hnh v, vi cc gi tr nh sau: in tr R = 100 Ohm. T in C = 100 F. Ngun xoay chiu: 6 V/50 Hz.

Hnh 2.1: Chnh lu ton k v lc RC

. - Dng sng ca mch khi cha mc t, ta nhn c sng c dng nh hnh bn di:

Hnh 2.2: Dng sng ca mch khi cha mc t.Trang:10

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

- Khi mc t C vo mch, quan st dng sng ta nhn c sng c dng nh hnh bn di:

Hnh 2.3: Dng sng khi mc t C. - Thay i gi tr ca t C v quan st dng sng: + Khi tng gi tr ca t C ln 1000 F, quan st dng sng ta thu c song c dng nh hinh bn di:

Hnh 2.4: Dng sng khi tng gi tr t C ln 1000 F.

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

+ Khi gim gi tr ca t xung cn 50 F , quan st dng sng ta thu c hnh nh bn di:

Hnh 2.5: Dng sng khi gim gi tr ca t cn 50 F. T cc dng sng nhn c cc hnh trn, ta rt ra nhn xt: + Khi cha mc t, do Diode c tc dng chnh lu dng xoay chiu thnh dng mt chiu nn sng ra l sng mt chiu nhng sng c gn sng cao(hnh 2.2). bn k dng Diode D1 dn, nhng Diode D2 khng dn. bn k m Diode D1 khng dn nhng Diode D2 dn c hai bn k u c dng chy qua ti nn sng li ra c lin tc. + Khi mc t C c in dung 100 F, nh c tnh np x ca t in nn sng ng ra c gn sng t hn so vi khi khng mc t (hinh 2.3). + Khi tng gi tr ca t ln 1000 F, nh c tnh np x ca t in dng in qua ti c lin tc v gn sng nh hn khi t c in dung 100 F (hnh 2.4). + Khi gim gi tr ca t in cn 50 F, sng li ra c gn sng thp hn so vi khi khng mc t nhng cao hn so vi khi t c in dung l 100 F v 1000 F (hnh 2.5). T cc kt qu trn ta rt ra nhn xt:

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GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

+ Mch hnh 2.1 l mch chnh lu ton k v hai bn k u c dng chy qua ti. S mch chnh lu hai na chu k s dng Diode chnh l hai s chnh lu mt na chu k mc song song c ti chung. + in dung ca t cng tng, kh nng tch in cng cao nn sng ra cng bng phng. + in dung ca t cng thp, kh nng tch in cng gim nn sng ra c gn sng cao hn. b. Mch chnh lu cu: in tr R = 100 Ohm T in C = 100 F. Ngun xoay chiu 6V/50Hz.

Hnh 2.6: Mch chnh lu cu.

- Khi cha mc t quan st dng sng ta c sng c dng nh hnh bn:

Hnh 2.7: Dng sng khi cha mc t.-

Khi mc t C, quan st dng sng ta thu c sng c dng nh hnh bn di:Trang:13

GVHD: Nguyn Hng Minh

Thc tp Mch Tng T

Hnh 2.8: Dng sng khi mc t. - Thay i gi tr ca t C v quan st dng sng: + Khi tng gi tr ca t C ln 200 F, quan st dng sng ta thu c sng c dng nh hnh bn:

Hnh 2.9: Dng sng khi tng gi tr t C ln 1000 F. + Khi gim gi tr ca t xung cn 50 F, quan st dng sng ca mch ta thu c sng c dng nh hnh bn:Trang:14

GVHD: Nguyn Hng Minh