Bài tập CKDT

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Lu :

Mi sinh vin hy t tr li cu hi v lm bi tp trc tip vo ti liu ny. Khng c sao chp bi gii ca ngi khc.

i vi phn cu hi trc nghim, SV lm bi chn mt phng n thch hp nht trong mi cu hi, bng cch khoanh trn hoc nh du vo u dng phng n c chn, v gii thch ngn gn vo phn trng bn cnh hoc pha di mi cu hi. i vi cc bi tp, hy ghi li gii vo ngay phn trng tng ng mi bi tp.

Ti liu tham kho: Bi ging Cu kin in t. 2001 [ D Quang Bnh ].

Electronic Devices. 2012 [Thomas L Floyd].

Fundamentals of Linear Electronics Integrated and Dicrete, 1998 [James

Cox ].

Lin h khi cn: Thy Bnh, 0905894666, hoc: [email protected]

Thi hn hon thnh v np bi tp: (vo bui thi . . . . . . . . . . . ) ti bm: K thut in t, khoa in t-Vin thng, Trng i hc Bch Khoa, 54 Nguyn Lng Bng, Q. Lin Chiu, Tp Nng. (Khng chp nhn s chm tr).

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TM TT NI DUNG V VT LIU BN DN & DIODE

1-1. Tun theo m hnh c hc c in Bohr, nguyn t c xem nh c cu trc kiu-h hnh

tinh vi cc qu o in t trn cc khong cch khc nhau xung quanh nhn trung tm. Tun theo m hnh c hc lng t, cc in t khng tn ti cc qu o trn chnh xc

nh cc ht c bn theo m hnh Bohr. Cc in t c th l sng hoc ht v nh v chnh xc ti thi im bt k l khng r rng.

Nhn ca nguyn t bao gm cc proton v cc neutron. Proton c in tch dng v neutron khng mang in tch. S lng cc proton l s nguyn t lng ca nguyn t.

Cc in t c in tch m v trn qu o xung quanh nhn ti cc khong cch ty thuc vo mc nng lng ca cc in t. Nguyn t c cc di nng lng gin on c gi l cc lp m trong l qu o ca in t. Cu trc nguyn t cho php s lng in t ln nht trong mi lp no . trng thi t nhin ca n, tt c cc in t u trung ha v in tch do cc nguyn t c s lng proton v electron bng nhau.

Lp hay di ngoi cng ca nguyn t c gi l di ha tr, nn cc in t c trn qu o di ny c gi l cc in t ha tr. Cc in t ha tr c mc nng lng cao nht trong tt c cc mc nng lng trong nguyn t. Nu mt in t ha tr nhn nng lng t mt ngun nng lng bn ngoi chng hn nhit nng, th in t c th nhy ra khi di ha tr v ri xa khi nguyn t ca n.

1-2. Vt liu cch in c rt t cc in t t do nn khng c dng in tt c cc iu kin thng thng.

Cc vt liu dn in c s lng ln cc in t t do nn dn dng in rt tt. Cc vt liu bn dn c dn in trong khong gia cc vt liu dn in v cch in. Cc nguyn t ca cht bn dn c bn in t ha tr. Silicon l vt liu bn dn c s

dng ph bin nht. Cc nguyn t ca cht bn dn lin kt vi nhau theo m hnh i xng to thnh vt liu

rn c gi l tinh th. Cc lin kt gi tinh th vi nhau c gi l cc lin kt ng ha tr.

1-3. in t ha tr thot khi nh hng nguyn t gc c gi l in t dn hay in t t do. Cc in t t do c nng lng cao hn so vi cc in t di ha tr, nn t do di chuyn trong khp vt liu.

Khi mt in t thot khi nh hng ca nhn tr nn t do, in t s li mt l trng trong di ha tr tc l to ra mt cp in t-l trng. Cc cp in t-l trng l c to ra do nhit nng bi v in t nhn nng lng nhit t ngoi thot khi nguyn t ca n.

Mt in t t do s mt nng lng cui cng ri tr li vo mt l trng. iu ny c gi l s ti hp. Cc cp in t-l trng c to ra lin tc do nhit nn lun lun c cc in t t do trong vt liu.

Khi t mt in p ngang qua mu vt liu bn dn, cc in t t do c to ra do nhit di chuyn v pha u dng v to thnh dng in. y l mt loi dng in c gi l dng in do in t.

Mt loi dng in khc l dng in do l trng. Dng in ny xut hin khi cc in t ha tr di chuyn khi l trng to nn l trng, trong thc t s di chuyn ca cc l trng theo chiu ngc li.

1-4. Vt liu bn dn tp dng-n c to ra bng cch b sung cc nguyn t tp cht c nm in t ha tr. Cc tp cht l cc nguyn t ha tr nm. Bn dn tp dng-p c to ra bng cch b sung cc nguyn t tp cht ch c ba in t ha tr. Cc tp cht l cc nguyn t ha tr ba.

Qu trnh b sung cc tp cht ha tr nm hoc ha tr ba vo mt cht bn dn c gi l pha tp.

Cc ht ti in a s trong vt liu bn dn tp dng-n l cc in t t do c c bng qu trnh pha tp, v cc ht ti in thiu s l cc l trng c to ra do nhit pht sinh cc cp in t-l trng. Cc ht ti in a s trong vt liu bn dn tp dng-p l cc l trng c

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c bi qu trnh pha tp, cn cc ht ti in thiu s l cc in t t do c to ra do nhit pht sinh cc cp in t-l trng.

1-5. Tip gip pn c hnh thnh khi mt phn vt liu c pha tp dng-n v mt phn vt liu c pha tp dng-p. Vng ngho s to thnh bt u ti tip gip tc l khng c cc ht ti in a s. Vng ngho c hnh thnh bi s i-on ha.

i vi tip gip silicon th chn in hnh l 0,7 V v i vi diode germanium l 0,3 V. 1-6. Dng in chy qua diode ch khi diode c phn cc thun. Xt theo l tng, khng c

dng in chy qua diode khi khng phn cc hoc phn cc ngc cho diode. Thc t, c dng in rt nh khi diode c phn cc ngc do cc ht ti in thiu s c to ra bi nhit nng, nhng mc dng ngc rt nh nn thng c th b qua.

S nh thng thc l xy ra khi diode c phn cc ngc nu in p phn cc bng hoc vt qu in p nh thng.

Diode s dn in khi c phn cc-thun v s ngng dn khi c phn cc-ngc. in p nh thng ngc ca mt diode thng ln hn 50 V.

1-7. c tuyn V-I th hin dng chy qua diode ph thuc vo in p st trn diode. in tr ca diode khi c phn cc-thun c gi l in tr ng hay in tr ac. Dng ngc chy qua diode s tng rt nhanh ti mc in p nh thng ngc. nh thng ngc cn phi trnh i vi phn ln diode.

1-8. M hnh l tng xem diode nh mt chuyn mch kn khi phn cc thun v nh mt h mch khi phn cc ngc.

M hnh thc t xem diode nh mt chuyn mch mc ni tip vi ngun th chn. M hnh y bao gm in tr thun ng mc ni tip vi m hnh thc t khi phn cc

thun v in tr ngc mc song song vi chuyn mch h khi phn cc ngc. 1-9. Ngun cung cp dc in hnh gm bin p, mch chnh lu bng diode, mch lc v b n

nh in p.

Diode n trong mch chnh lu bn k khi c phn cc-thun s dn trong khong 180 ca chu k tn hiu vo.

Tn s ca tn hiu ra mch chnh lu bn k bng tn s tn hiu vo. in p ngc nh (PIV) l mc in p ln nht ngang qua diode khi phn cc ngc.

1-10. Mi diode trong mch chnh lu ton k khi c phn cc-thun s dn trong khong 180 ca chu k tn hiu vo

Tn s ca tn hiu ra mch chnh lu ton k l gp hai ln tn s tn hiu vo. Hai kiu mch chnh lu ton k c bn l mch cu v mch cun dy im gia. in p ra nh ca mch chnh lu ton k im gia xp x bng mt na in p th cp

nh ton b tr st p ca mt diode. PIV ca mi diode trong mch chnh lu ton k im gia l gp hai ln in p ra nh

cng vi mc st p trn mt diode. in p ra nh ca mch chnh lu cu bng in p th cp nh ton b tr st p trn hai

diode.

PIV ca mi diode trong mch chnh lu cu xp x bng mt na in p i vi cu hnh im gia tng ng v bng in p ra nh cng vi mc st p trn mt diode.

1-11. B lc u vo bng t s cung cp mc in p ra dc xp x bng mc nh ca in p p vo c chnh lu.

in p gn c pht sinh do s np v x ca t lc. Lc tt hn khi mc in p gn nh hn. S n nh in p ra trn mt khong in p vo c gi l n nh u vo hay n nh

ngun cung cp. S n nh in p ra trn mt khong dng ti c gi l n nh ti.

1-12. B xn hay mch hn bng diode ch s ct in p cao hn hay thp hn cc mc c quy nh.

B ghim bng diode b sung mc dc i vi in p ac. 1-13. Cc b nhn p c s dng trong cc ng dng in p-cao, dng-thp chng hn nh dng

gia tc chm tia in t trong ng tia (CRT) v dng gia tc ht c bn. nhn p s dng hng lot cc tng diode-t in. in p t vo c th c nhn i, nhn ba, hoc nhn 4.

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1-14. Trang s liu (datasheet) cho bit thng tin chnh v cc thng s v cc c tuyn ca mt cu kin in t.

Diode cn phi lun lun lm vic di cc thng s ln nht xc thc c quy nh trang s liu.

1.15. Nhiu DMM cho chc nng o th diode. DMM hin th st p ca diode khi diode lm vic ng phn cc thun. Phn ln cc DMM ch th OL khi diode h mch. X l s c l p dng suy xt hp l kt hp vi kin thc y v mch hoc h thng

nhn dng v sa cha sai hng. X l s c l qu trnh ba-bc gm phn tch, c lp v o. Phn tch li l c lp h hng cho mt mch c th hay mt phn ca mch.

1.16. Diode n p [zener] hot ng vng nh thng ngc. C hai c ch nh thng diode n p: l nh thng thc l v nh thng zener.

Khi 6,3 VZV nh thng zener chim u th.

Khi 6,3 VZV nh thng thc chim u th.

Diode n p s duy tr in p gn nh khng i trn hai in cc ca n trong khong dng in zener quy nh.

Diode n p c sn nhiu cp in p t di 1 V n trn 250 V. 1.17. Diode n p c s dng lm cc ngun in p chun, cc n p, v cc b hn ch. 1.18. Diode bin dung [varactor] hot ng nh mt t thay i trng thi phn cc-ngc.

in dung ca varactor bin thin t l nghch vi in p phn cc-ngc. Diode n nh dng s duy tr dng thun ca n ti gi tr khng i c quy nh.

1.19. Diode pht quang [LED] s pht ra nh sng khi c phn cc-thun. Cc LED c sn pht ra hng ngoi hoc nh sng nhn thy. Cc LED cng sng-cao c s dng trong cc b hin th mn hnh-ln, n giao

thng, n chiu sng -t v n chiu sng trong nh. LED hu c [OLED] s dng hai hay ba lp vt liu hu c to ra nh sng. Cc im lng t l cc cu kin bn dn pht ra nh sng khi c cung cp nng lng t

ngun bn ngoi. Photodiode biu hin s tng ln v dng ngc theo cng chiu sng.

1.20. Diode Schottky c tip gip kim loi-bn dn. Diode Schottky c s dng trong cc ng dng tc chuyn mch-cao.

Diode tunnel c s dng trong cc mch dao ng. Diode pin c vng bn dn tp-p, vng bn dn tp-n, v vng bn dn nguyn cht (i) nn s

biu hin c tnh ca in tr bin thin khi c phn cc-thun v in dung khng i khi c phn cc-ngc.

Diode laser tng t LED ngoi tr diode laser pht ra nh sng kt hp (bc sng n) khi dng thun vt qu gi tr ngng.

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1-1. S lng in t ln nht trong mt lp bt k: 22eN n

1-2. Dng thun theo m hnh l tng ca diode: BIASFLIMIT

VI

R

1-3. Dng thun theo m hnh thc t ca diode: BIAS FFLIMIT

V VI

R

1-4. Gi tr trung bnh ca in p ra mch chnh lu bn k: AVG

pVV

1-5. in p ra nh ca chnh lu bn k (silicon): ( ) ( ) - 0,7 Vp out p inV V

1-6. in p ngc nh mch chnh lu bn k: ( )PIV p inV

1-7. Gi tr trung bnh ca in p chnh lu ton k: AVG

2 pVV

1-8. in p ra ca chnh lu ton k im gia: - 0,7 V2

secout

VV

1-9. in p ngc nh mch chnh lu ton k im gia: ( )PIV 2 + 0,7 Vp outV

1-10. in p ra ca chnh lu cu ton k: ( ) ( ) - 1,4 Vp out p secV V

1-11. in p ngc nh mch chnh lu cu ton k: ( )PIV + 0,7 Vp outV

1-12. H s gn: ( )

DC

r ppVr

V

1-13. in p gn nh-nh khi c t lc u vo: ( ) ( )

1r pp p rect

L

V VfR C

1-14. in p ra DC khi c t lc u vo: DC ( )

11

2p rect

L

V VfR C

1-15. n nh ngun: OUT

IN

Line regulation 100%V

V

1-16. n nh ti: NL FL

FL

Load regulation 100%V V

V

1-17. Tr khng ca Zener: Z

ZZ

VZ

I

1-18. thay i ca ZV khi TC tnh theo %/C: Z ZZ V TC T

1-19. thay i ca ZV khi TC tnh theo mV/C: ZZ TC T

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Cu hi v vt liu bn dn v diode

1. Mi nguyn t bit u c (a) kiu cc nguyn t ng nht; (b) s lng cc nguyn t nh nhau; (c) kiu nguyn t duy nht; (d) nhiu kiu nguyn t khc nhau.

2. Mt nguyn t bao gm (a) mt nhn v ch mt in t; (b) mt nhn v mt hoc nhiu in t; (c) cc proton, cc in t, v cc neutron; (d) c (b) v (c).

3. Nhn ca mt nguyn t c to thnh bi (a) cc proton v cc neutron; (b) cc in t; (c) cc in t v cc proton; (d) cc in t v cc neutron.

4. in t ha tr c (a) qu o gn nhn nht; (b) qu o xa nhn nht; (c) cc qu o khc nhau xung quanh nhn; (d) khng lin quan vi nguyn t ring bit.

5. I-on dng c to thnh khi (a) mt in t ha tr thot ra xa khi nguyn t; (b) c nhiu l trng hn so vi in t qu o ngoi cng; (c) hai nguyn t lin kt vi nhau; (d) mt nguyn t nhn thm mt in t ha tr.

6. Vt liu bn dn c s dng ph bin nht trong cc cu kin in t l (a) germanium; (b) carbon; (c) copper; (d) silic.

7. S khc nhau gia cht cch in v cht bn dn l (a) khe nng lng gia di ha tr v di dn rng hn; (b) s lng in t t do; (c) cu trc nguyn t; (d) c (a), (b), v (c).

8. Di nng lng m trong cc in t t do tn ti l (a) di th nht; (b) di th hai; (c) di dn; (d) di ha tr.

9. Trong tinh th bn dn, cc nguyn t c lin kt vi nhau do (a) s tng tc ca cc in t ha tr; (b) cc lc hp dn; (c) cc lin kt ng ha tr; (d) c (a), (b), v (c).

10. S nguyn t lng ca silicon l (a) 8; (b) 2; (c) 4; (d) 14.

11. S nguyn t lng ca germanium l (a) 8; (b) 2; (c) 4; (d) 32.

12. Lp ha tr mt nguyn t silicon c s th t l (a) 0; (b) 1; (c) 2; (d) 3.

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13. Mi nguyn t trong tinh th silicon c (a) bn in t ha tr; (b) bn in t trong di dn; (c) tm in t ha tr, 4 in t ca chnh nguyn t v 4 in t c gp chung; (d) khng c cc in t ha tr do tt c in t c gp chung vi cc nguyn t khc.

14. Cc cp in t - l trng c to thnh bi (a) s ti hp; (b) nng lng nhit; (c) s ion ha; (d) s pha tp.

15. C s ti hp khi (a) mt in t ri vo mt l trng; (b) mt ion dng v mt ion m lin kt vi nhau; (c) in t di ha tr tr thnh in t di dn; (d) mt tinh th c hnh thnh.

16. Dng in trong cc cht bn dn c to ra bi (a) ch do cc in t; (b) ch do cc l trng; (c) cc i-on m; (d) c cc in t v cc l trng.

17. Trong cht bn dn thun (c bn) (a) khng c cc in t t do; (b) cc in t t do c to ra do nhit; (c) ch c cc l trng; (d) c bao nhiu in t s c by nhiu l trng; (e) gm c (b) v (d).

18. Qu trnh b sung tp cht vo cht bn dn thun gi l (a) s pha tp; (b) s ti hp; (c) s bin i nguyn t; (d) s ion ha.

19. Tp cht ha tr 3 c b sung vo silicon to thnh (a) germanium; (b) cht bn dn tp dng-p; (c) cht bn dn tp dng-n; (d) vng ngho.

20. Chc nng ca tp cht ha tr 5 l (a) lm gim dn in ca silicon; (b) tng s lng l trng; (c) lm tng s lng cc in t t do; (d) to ra cc ht ti in thiu s.

21. Cc ht ti in a s trong bn dn tp dng-n l (a) cc l trng; (b) cc in t ha tr; (c) cc in t trong di dn; (d) cc proton.

22. Cc l trng trong bn dn tp dng-n l

(a) ht ti in thiu s c to ra do nhit;(b) ht ti in thiu s c to ra do pha tp; (c) cc ht ti in a s c to ra do nhit;(d) cc ht ti in a s c to ra do pha tp.

23. Tip gip pn c to thnh do

(a) s ti hp ca cc in t v l trng; (b) s i-on ha; (c) bin gii ca vt liu dng-p v dng-n; (d) s va chm ca mt proton v mt neutron.

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24. Vng ngho c to ra do (a) s i-on ha; (b) s khuych tn; (c) s ti hp; (d) gm c (a), (b), v (c).

25. Vng ngho gm (a) vng khng c g c ngoi cc ht ti in thiu s; (b) cc i-on dng v m; (c) khng c cc ht ti in a s; (d) c (b) v (c).

26. Thut ng phn cc [bias] c ngha l (a) t s ca ht ti in a s i vi ht ti in thiu s; (b) mc dng in chy qua diode; (c) mc in p dc t vo iu khin s hot ng ca mt cu kin; (d) ngoi cc phng n trn.

27. phn cc thun mt diode

(a) in p ngoi t vo l dng ti anode v m ti cathode; (b) in p ngoi t vo l m ti anode v dng ti cathode; (c) in p ngoi t vo l dng ti vng p v m ti vng n; (d) c (a) v (c).

28. Khi mt diode c phn cc thun,

(a) dng in duy nht l dng l trng; (b) dng in duy nht l dng in t; (c) dng in duy nht l c to ra do cc ht ti in a s; (d) dng in c to ra do c cc l trng v cc in t.

29. Mc d dng in b ngng khi phn cc ngc, (a) nhng c mt mc dng in no do cc ht ti in a s; (b) nhng c mt mc dng in rt nh do cc ht ti in thiu s; (c) nhng c dng do nh thng thc.

30. i vi mt diode silicon, tr s ca in p phn cc thun in hnh

(a) cn phi ln hn 0,3V; (b) cn phi ln hn 0,7V; (c) ty thuc vo rng ca vng ngho; (d) ph thuc vo nng ca ht ti in a s.

31. Khi c phn cc thun, diode s (a) ngng dn; (b) dn dng; (c) c in tr cao; (d) st gim mc in p ln.

32. Mt diode thng lm vic

(a) vng nh thng ngc; (b) vng phn cc-thun; (c) vng phn cc-ngc; (d) hoc (b) hoc (c).

33. in tr ng c th quan trng khi diode

(a) c phn cc ngc; (b) c phn cc-thun; (c) vng nh thng-ngc; (d) cha c phn cc.

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34. c tuyn I-V ca diode th hin (a) in p ngang qua diode theo mc dng cho; (b) mc dng in theo mc in p phn cc cho; (c) tiu tn cng sut; (d) ngoi cc phng n trn.

35. Xt mt cch l tng, mt diode c th c tng ng vi mt (a) ngun in p; (b) in tr; (c) chuyn mch; (d) tt c cc phn t trn.

36. M hnh diode thc t l (a) mc th ro c a vo tnh ton; (b) gi tr in tr ng c a vo tnh ton; (c) ngoi hai trng hp (a) v (b); (d) c (a) v (b).

37. Trong m hnh diode y , (a) mc th ro c a vo tnh ton; (b) tr s in tr ng thun c a vo tnh ton; (c) tr s in tr ngc c a vo tnh ton; (d) tt c cc thng s trn.

38. Gi tr trung bnh ca in p chnh lu bn k vi tr s nh 200 V l (a) 63,7 V; (b) 127,2 V; (c) 141 V; (d) 0 V.

39. Khi t in p sinusoidal 60 Hz vo u vo ca mch chnh lu bn k, tn s tn hiu ra l (a) 120 Hz; (b) 30 Hz; (c) 60 Hz; (d) 0 Hz.

40. Gi tr nh ca in p ti u vo ca mch chnh lu bn k l 10 V. Gi tr nh gn ng ca in p ti u ra l (a) 10 V; (b) 3,18 V; (c) 10,7 V; (d) 9,3 V.

41. i vi mch cu hi 40, diode cn phi c kh nng chu in p ngc l (a) 10 V; (b) 5 V; (c) 20V; (d) 3,18 V.

42. Gi tr trung bnh ca in p c chnh lu ton k vi tr s nh 75 V l (a) 53 V; (b) 47,8 V; (c) 37,5 V; (d) 23,9 V.

43. Khi t in p sinusoidal 60 Hz vo u vo ca mch chnh lu ton k, tn s tn hiu ra l (a) 120 Hz; (b) 60 Hz; (c) 240 Hz; (d) 0 Hz.

44. in p th cp ton b mch chnh lu ton k im-gia l 125 V rms. B qua st p ca diode, in p ra hiu dng (V rms) l

(a) 125 V; (b) 177 V; (c) 100 V; (d) 62,5 V.

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45. Khi in p ra nh l 100 V, tr s in p ngc nh (PIV) cn phi c cho mi diode trong mch chnh lu ton k im gia l (b qua st p ca diode) (a) 100 V; (b) 200 V; (c) 141 V; (d) 50 V.

46. Khi in p ra hiu dng (rms) ca mch chnh lu cu ton k l 20 V, in p ngc nh ngang qua cc diode l (b qua st p trn diode) (a) 20 V; (b) 40 V; (c) 28,3 V; (d) 56,6 V.

47. in p ra dc l tng ca mch lc u vo bng t s bng vi (a) gi tr nh ca in p c chnh lu; (b) gi tr trung bnh ca in p c chnh lu; (c) gi tr hiu dng ca in p c chnh lu.

48. Mt b lc ngun cung cp cho in p ra c gn l 100 mV nh-nh v gi tr dc l 20 V?. H s gn l (a) 0,05; (b) 0,005; (c) 0,00005; (d) 0,02.

49. in p c chnh lu ton k nh l 60 V t vo mch lc u vo bng t. Nu f = 120

Hz; =10 kLR , v =10 FC , in p gn l

(a) 0,6 V; (b) 6 mV; (c) 5,0 V; (d) 2,88 V.

50. Nu gim in tr ti ca b chnh lu ton k c lc bng t, th in p gn (a) s tng ln; (b) s gim xung; (c) khng nh hng; (d) c tn s khc.

51. n nh theo in p ngun c xc nh bng (a) dng ti; (b) dng zener v dng ti; (c) thay i in tr ti v in p ra; (d) thay i in p ra v in p vo.

52. n nh theo ti c xc nh bng (a) cc thay i dng ti v in p vo; (b) cc thay i dng ti v in p ra; (c) cc thay i in tr ti v in p vo;(d) cc thay i dng zener v dng ti.

53. t in p sinusoidal 10 Vnh-nh vo mch diode silicon v in tr mc ni tip. Tr s in p ln nht ngang qua diode l (a) 9,3 V; (b) 5 V; (c) 0,7 V; (d) 4,3 V.

54. Trong mch xn c phn cc, in p phn cc l 5 V v in p vo l dng sin 10 V nh. Nu cc tnh dng ca in p phn cc c ni vi cathode ca diode, th in p ti anode l (a) 10 V; (b) 5 V; (c) 5,7 V; (d) 0,7 V.

55. Trong mch ghim p dng, in p t vo u vo l dng sin 120 V rms. Gi tr ca in p dc u ra l (a) 119,3 V; (b) 169 V; (c) 60 V; (d) 75,6 V.

-12-

56. in p u vo ca b nhn i in p l 120 V rms. Gi tr gn ng ca in p ra nh-nh l

(a) 240 V; (b) 60 V; (c) 167 V; (d) 339 V.

57. Nu in p u vo ca b nhn ba in p c gi tr hiu dng l 12 V, Gi tr in p ra dc gn ng l (a) 36 V; (b) 50,9 V; (c) 33,9 V; (d) 32,4 V.

58. Khi mt diode silicon hot ng ng phn cc thun, DMM chc nng o th diode s ch th (a) 0 V; (b) OL; (c) xp x 0,7 V; (d) xp x 0,3 V.

59. Khi mt diode silicon b h mch, DMM thng thng s ch th (a) 0 V; (b) OL; (c) xp x 0,7 V; (d) xp x 0,3 V.

60. Trong mt mch chnh lu, nu cun dy th cp ca bin p h mch, th in p ra l (a) 0 V; (b) 120 V; (c) thp hn nh mc; (d) khng nh hng.

61. Nu mt trong cc diode trong mch chnh lu cu ton k b h mch, th in p ra l (a) 0 V; (b) mt phn t bin ca in p vo; (c) bng in p chnh lu bn k; (d) in p 120 Hz.

62. Khi kim tra mt mch chnh lu cu ton k 60 Hz cho thy tn hiu ra c gn 60 Hz, (a) mch hot ng bnh thng; (b) c mt diode b h mch; (c) cun th cp ca bin p b ngn mch; (d) t lc b r.

63. Khi t voltmeter ngang qua diode c phn cc thun, th voltmeter s ch th mc in p xp x bng vi (a) mc in p ca ngun pin phn cc; (b) 0V; (c) th ro ca diode; (d) in p ca ton b mch.

64. Mt diode silicon mc ni tip vi in tr 1,0k v mt ngun pin 5V. Nu anode c mc vi cc dng ca ngun pin, in p cathode so vi u m ca ngun pin l (a) 0,7V; (b) 0,3V; (c) 5,7V; (d) 4,3V.

65. u que o dng ca ng h o in tr [ohmmeter] c kt ni vi anode ca diode cn u que m l kt ni vi cathode. Diode l (a) c phn cc ngc; (b) h mch; (c); c phn cc thun (d) b hng; (e) gm c (b) v (d).

66. Cathode ca diode zener mc trong b n nh in p thng l (a) dng hn so vi anode; (b) m hn so vi anode; (c) mc in p + 0,7V; (d) c ni t.

-13-

67. Nu mt diode zener c in p zener l 3,6V th diode zener s lm vic (a) vng nh thng c n inh; (b) vng nh thng zener; (c) vng dn thun; (d) vng nh thng thc.

68. Mt diode zener 12V, thay i dng zener 10mA s to ra thay i in p zener l 0,1V. Tr khng ca zener tng ng vi khong dng trn l

(a) 1; (b) 100; (c) 10; (d) 0,1.

69. S liu ca mt diode zener cho l VZ = 10V o ti mc dng IZT = 500mA. ZZ tng ng l

(a) 50; (b) 20; (c) 10; (d) cha bit.

70. Trng thi khng-ti c ngha l (a) ti c in tr v cng; (b) ti c in tr bng khng; (c) cc u ra l h mch; (d) gm c (a) v (c).

71. Diode bin dung biu hin (a) in dung c th thay i ty thuc vo in p ngc; (b) in tr c th thay i ty thuc vo in p ngc; (c) in dung c th thay i ty thuc vo in p thun; (d) in dung khng i trong khong in p ngc.

72. Diode pht quang - LED

(a) s pht sng khi c phn cc ngc; (b) s nhy cm vi nh sng khi phn cc ngc; (c) s pht sng khi c phn cc thun; (d) hot ng nh mt bin tr.

73. LED hng ngoi so vi LED thy c l (a) to ra nh sng c bc sng ngn hn; (b) to ra nh sng tt c cc bc sng; (c) to ra ch mt mu ca nh sng; (d) to ra nh sng c bc sng di hn.

74. So vi cc n si t, LED cng sng-cao l (a) sng hn; (b) bn hn; (c) s dng ngun thp hn;(d) tt c cc c tnh trn.

75. OLED khc vi LED thng thng c tnh l OLED (a) khng cn in p phn cc; (b) c cc lp vt liu hu c thay cho tip gip pn; (c) c th thc hin c khi s dng qu trnh in phun; (d) c (b) v (c).

76. LED hng ngoi c ghp quang vi photodiode. Khi LED tt, th ch th trn ng h o dng mc ni tip vi photodiode c phn cc-ngc s l (a) khng thay i; (b) gim xung; (c) tng ln; (d) dao ng .

77. in tr ni ca quang diode - photodiode (a) s tng ln theo cng nh sng khi c phn cc-ngc; (b) s gim xung theo cng nh sng khi c phn cc-ngc; (c) s tng ln theo cng nh sng khi c phn cc-thun; (d) s gim xung theo cng nh sng khi c phn cc-thun.

-14-

78. Diode laser s to ra (a) nh sng khng kt hp; (b) nh sng kt hp; (c) nh sng n sc; (d) c (b) v (c).

79. Diode c c tnh in tr m l (a) diode Schottky; (b) diode tunnel; (c) diode laser; (d) diode ht ti nng [hot-carrier diode].

80. cho mt h thng hot ng ng chc nng, th cc loi mch khc nhau to nn h thng cn phi (a) c phn cc ng; (b) c kt ni ng; (c) c giao tip ng; (d) tt c cc phng n trn; (e) gm c (a) v (b).

-15-

BI TP

BI TP C BN

Mc 1-1 Cu trc nguyn t

1. Nu s nguyn t ca mt nguyn t trung ha l 6, th c bao nhiu in t c trong nguyn t? proton l bao nhiu?.

2. S lng in t ln nht l bao nhiu c th c lp th 3 ca mt nguyn t?

Mc 1-2 Vt liu s dng trong cu kin in t

3. Vi mi gin nng lng hnh 1.40, hy xc nh loi vt liu da trn cc so snh tng i.

4. Mt nguyn t c 4 in t ha tr. Kiu nguyn t l thuc loi vt liu no?

5. Trong tinh th silicon, mu nguyn t n thc hin bao nhiu lin kt ng ha tr?

Mc 1-3 Dng in trong cc cht bn dn

6. iu g xy ra khi gia tng nhit vo silicon?

7. Tn gi hai vng nng lng m trong dng in s c to ra trong cht bn dn?

Mc 1-4 Cc cht bn dn tp dng-N v dng-P

8. Hy m t qu trnh pha tp v gii thch qu trnh pha tp bin i cu trc nguyn t ca silicon nh th no?

-16-

9. Nguyn t antimony c bao nhiu in t ha tr, c th s dng lm g trong ch to cht bn dn? Nguyn t boron c bao nhiu in t ha tr, c th s dng lm g trong ch to cht bn dn?

Mc 1-5 Tip gip PN

10. in trng tip gip pn c to ra nh th no?

11. Do c th chn [barrier potential], diode c th c dng lm ngun in p c khng? Gii

thch.

Mc 1-6 Hot ng ca diode

12. diode c phn cc thun, cn phi mc u dng ca ngun in p n vng bn dn no ca tip gip?

13. Hy gii thch ti sao cn phi c in tr mc ni tip khi diode c phn cc thun.

Mc 1-7 c tuyn Dng-Ap ca diode

14. Gii thch cch to ra phn c tuyn phn cc thun ca diode nh th no?

15. Bng cch no c th lm cho ro th gim t 0,7V xung 0,6V?

Mc 1-8 Cc m hnh ca diode

16. Hy xc nh mi diode mch hnh 1.41, l c phn cc thun hay phn cc ngc.

17. Hy xc nh in p trn mi diode mch hnh 1.41, theo m hnh thc t ca diode.

-17-

18. Hy xc nh in p trn mi diode mch hnh 1.41, bng m hnh diode l tng

19. Hy xc nh in p trn mi diode mch hnh 1.41, s dng m hnh diode y c 10 dr' v 100 MRr' .

Mc 1-10 Chnh lu bn k

20. Hy v dng sng v ghi tr s ca in p ra cho mi mch hnh 2.68.

21. in p ngc nh trn mi diode hnh 2.68 l bao nhiu?.

22. Tnh gi tr trung bnh ca in p ca in p c chnh lu bn k vi gi tr in p nh l

200 V.

23. Tnh gi tr trung bnh ca in p ca in p c chnh lu bn k c gi tr in p nh l

200 V.

24. Gi tr dng thun nh chy qua mi diode mch hnh 2.68, l bao nhiu?

25. Bin p ngun cung cp c t s vng dy l 5:1. in p th cp l bao nhiu nu cun dy s

cp c ni vi ngun 120 V rms?

26. Xc nh mc cng sut nh v trung bnh c phn b n RL mch hnh 2.69.

-18-

Mc 1-11 Mch chnh lu ton k

27. Tnh tr trung bnh cho mi in p ghi hnh 2.70.

28. Xt mch hnh 2.71. (a) Kiu mch ny l mch g?

(b) in p nh th cp ton b l bao nhiu?

(c) Tnh in p nh trn mi na cun dy th cp.

(d) V dng sng in p trn RL.

(e) Mc dng nh chy qua mi diode l bao nhiu?

(f) PIV ca mi diode trong mch l bao nhiu?

29. Tnh in p nh trn mi na ca bin p im gia cun dy c dng trong b chnh lu ton k c mc in p ra trung bnh l 120V.

30. Hy trnh by cch mc cc diode b chnh lu im gia nh th no to ra in p ton k m trn in tr ti.

31. Thng s PIV cn phi c l bao nhiu cc diode trong mch chnh lu cu to ra mc in p ra trung bnh l 50V?

32. in p ra ca mch chnh lu cu l 20V. Mc in p ngc nh trn cc diode l bao nhiu?

33. V dng sng in p ra ca mch chnh lu cu hnh 2.72. Lu l ton b diode c o ngc so vi cc mch trc y.

-19-

Mc 1-12 Mch lc ngun cung cp v n nh in p

34. Mch lc ca b chnh lu cung cp in p ra dc l 75V vi in p gn nh-nh l 0,5V. Tnh h s gn.

35. Mch chnh lu ton k c mc in p ra nh l 30V. B lc u vo bng t 50 F s c

mc vi b chnh lu. Tnh mc gn nh-nh v mc in p ra dc trn in tr ti 600.

36. Mc gn theo phn trm ca mch lc chnh lu bi tp 35 l bao nhiu?

37. Tr s ca t lc cn phi c l bao nhiu cho h s gn 1% ca b chnh lu ton k c in

tr ti l 1,5k? Cho bit b chnh lu cung cp mc in p ra nh l 18V.

38. Mch chnh lu ton k c mc in p chnh lu nh l 80V t ngun ac 60Hz. S dng t lc

10F, xc nh h s gn vi in tr ti l 10k.

39. Tnh mc gn nh-nh v mc in p ra dc mch hnh 2.73. Bin p c thng s in p th cp l 36 V rms, v in p ngun in c tn s 60Hz.

40. Xt mch hnh 2.73, v v dng sng in p theo quan h vi in p vo: VAB, VAD, v VCD.

41. Nu in p ra khng ti ca b n nh in p l 15,5V v in p ra y ti l 14,9V, th n nh ti theo phn trm l bao nhiu?

42. Cho b n nh in p c n nh ti theo phn trm l 0,5%. Mc in p ra y ti l bao nhiu nu mc in p ra khng ti l 12,0V?.

-20-

Mc 1-13 Cc mch hn ch v mch ghim bng diode

43. Hy xc nh dng sng ra cho mch hnh 2.74.

44. Hy xc nh in p ra cho mch hnh 2.75(a) tng ng vi mi in p vo hnh 2.75(b), (c), v (d).

45. Hy xc nh dng sng ca in p ra cho mch hnh 2.76.

-21-

46. Hy xc nh dng sng ca in p trn ti RL cho mi mch hnh 2.77.

47. Hy v dng sng ca in p ra cho mi mch hnh 2.78.

48. Hy xc nh dng sng ca in p ra cho mi mch hnh 2.79.

-22-

49. Hy xc nh dng sng ca in p ra cho mi mch hnh 2.80. Cho bit hng s thi gian RC l ln hn nhiu so vi chu k ca tn hiu vo.

50. Lp li bi tp 49 vi cc diode c mc xoay ngc chiu.

Mc 1-14 Mch nhn p

51. Mt mch bi p c in p u vo l 20 Vrms. Mc in p u ra l bao nhiu? Hy v mch, ch th ti cc u ra v thng s PIV ca diode.

52. Lp li bi tp 51 cho b nhn 3 in p v b nhn 4 in p.

Mc 1-15 Thng s ca diode

53. T trang s liu hnh 2.55, hy xc nh in p ngc nh l bao nhiu m diode 1N183A c th chu ng c.

-23-

54. Lp li nh bi tp 53 cho diode 1N188A.

55. Nu in p ra nh ca mch chnh lu cu ton k l 50V, xc nh tr s nh nht ca in tr hn ch xung gn cn thit khi s dng diode 1N183A.

Mc 1-16 Sai hng trong mch diode

56. Nu 1 trong s cc diode b chnh lu cu b h mch, th in p ra s nh th no?

-24-

57. T cc s ch th trn ng h o mch hnh 2.81, hy xc nh xem b chnh lu ang hot ng bnh thng khng? Nu khng bnh thng, xc nh h hng c th d xy ra nht.

58. Hnh 2.82, l th hin dng sng in p ra ca cc mch chnh lu khc nhau hin th trn my hin sng. Theo mi trng hp, hy xc nh mch chnh lu c hot ng ng chc nng khng v nu khng ng chc nng th hy xc nh h hng c th d xy ra nht.

59. Cn c vo cc gi tr (ghi trong mch)ca cu kin cho, mch hnh 2.83 c th h hng khng? Nu nh vy th ti sao?

-25-

60. Xem cc s ch th trn ng h o trong mi mch hnh 1.42, v xc nh diode no ng chc nng, hay diode no h mch hoc b ngn mch. Gi s m hnh l tng.

61. Hy xc nh in p so vi t ti tng im o trong mch hnh 1.43. Gi s m hnh diode thc t.

62. Hy xc nh sai hng c th d xy ra nht trong bng mch hnh 2.84 theo mi hin trng di y. Trng thi hot ng lin quan cn phi ly theo tng trng hp. Bin p c mc in p ra nh mc l 36V.

(a) Khng o c in p t im o 1 i vi im o 2. (b) Khng c in p t im 3 i vi im o 4, 110V rms o gia im o 1 v im o 2.

(c) 50V t im o 3 i vi im o 4. in p vo ng mc 110V rms.

(d) 25V t im o 3 i vi im o 4. in p vo ng mc 110V rms.

(e) in p chnh lu ton k c mc nh khong 50V ti im o 7 so vi t.

(f) in p gn 120Hz cao ti im o 7.

(g) in p gn c tn s 60Hz ti im o 7.

(h) Khng c in p ti im o 7.

-26-

63. Khi o th bng mch ngun cung cp hnh 2.84 c mc in tr ti 10k, o in p ti u dng ca t lc c in p gn 60Hz. Thay ton b diode, cm phch in ngun vo bng mch, v o li im o kim chng hot ng c ng khng v thy rng in p o vn c in p gn 60Hz. Sai hng lc ny l g?

64. Nu diode pha trn cng bng mch hnh 2.84, lp sai b o ngc, th in p c th o

c ti im o 8 l bao nhiu?

65. Mt mch chnh lu ton k c t lc cung cp in p ra dc l 35V cho ti 3,3k. Hy xc nh tr s nh nht ca t lc nu mc in p gn nh-nh yu cu l 0,5V.

66. Mt mch chnh lu ton k cha lc vi mc in p vo l 220V; 50Hz cung cp in p ra c

mc nh l 15V. Khi mc mch lc u vo bng t v ti l 1k, in p ra dc l 14V. Mc in p gn nh-nh l bao nhiu?

67. Vi mt b chnh lu ton k, dng xung o c b lc bng t l 50A. Bin p c thng s in p th cp l 24V vi in p vo l 120V; 60Hz. Hy tnh tr s ca in tr xung gn cn trong mch ny.

68. Thit k b chnh lu ton k s dng bin p im gia 18V. gn u ra khng vt qu

5% bin in p ra, vi in tr ti l 680. Ch r cc thng s nh mc Io v PIV ca cc diode v chn diode thch hp t hnh 2.55.

69. Thit k b ngun cung cp c lc c th cho cc mc in p ra l + 9V 10% v - 9V 10% vi mc dng ti ln nht l 100mA. Hai mc in p phi c chn bng chuyn mch thit lp hai u ra. in p gn cn phi khng vt qu 0,25V rms.

-27-

70. Thit k mch xn in p sin 20V rms thnh in p xung c bin dng ln nht l 18V v bin m ln nht l 10V s dng ngun in p dc n 24V.

71. Hy xc nh mc in p trn mi t trong mch hnh 2.85.

Mc 1-17 Diode n p

72. Mt diode zener c VZ = 7,5V v ZZ = 5 ti mc dng o. V mch tng ng ca zener.

73. T c tuyn hnh 3.58, dng zener nh nht (IZK), in p zener ti mc IZK gn ng l bao nhiu?

74. Khi dng ngc trong mt diode zener tng ln t 20mA n 30mA, th in p zener s thay i t 5,6V n 5,65V. Tr khng ca zener l bao nhiu?

75. Mt diode zener c tr khng l 15. in p u cc ca zener l bao nhiu ti mc dng 50mA nu VZ = 4,7V ti mc dng IZ = 25mA?

76. Mt diode zener c cc thng s sau: VZ = 6,8V ti 25C v h s nhit TC = + 0,04% / C.

Hy xc nh in p zener ti 70C.

Mc 1-18 Cc ng dng ca diode n p

77. Xc nh mc in p vo thp nht cn thit c s n nh cho mch c thit lp nh hnh 3.59. Gi thit diode zener l tng c IZK = 1,5mA v VZ = 14V.

-28-

78. Lp li nh bi tp 77, vi ZZ = 20 v VZ = 14V ti mc dng 30mA.

79. Cn phi iu chnh R trong mch hnh 3.60, n gi tr no to ra IZ = 40mA? Cho VZ =

12V ti mc dng 30mA v ZZ = 30.

80. t in p sin 20V nh vo mch hnh 3.60, thay cho ngun dc. V dng sng ra. S dng gi tr ca cc thng s cho bi tp 79.

81. B n nh bng zener c ti nh hnh 3.61. VZ = 5,1V ti IZ = 49mA; IZK = 1mA; ZZ

= 7 , v IZM = 70mA. Xc nh cc mc dng ti cho php ln nht v nh nht.

82. Tnh n nh ti theo phn trm cho bi tp 81.

[ NL FL

FL

Load regulation = 100%V V

V

]

83. Phn tch mch hnh 3.61, c n nh ngun tnh theo phn trm khi s dng in p vo t 6V n 12V khng ti.

[ OUT

IN


V

]

84. Mch n nh bng zener c in p ra khng ti, VNL= 8,23V, v in p ra y ti VFL= 7,98V.

Tnh n nh ti tnh theo phn trm. [ NL FL

FL


V

]

85. b n nh bng zener, khong thay i ca in p ra l 0,2V khi in p vo t 5V n 10V.

n nh ngun theo phn trm l bao nhiu? [ OUT

IN


V

]

86. in p ra ca b n nh bng zener l 3,6V khi khng ti v 3,4V khi y ti. Tnh n nh

ti theo phn trm. [ NL FL

FL


V

]

-29-

Mc 1-19 Diode bin dung - VARACTOR

87. Hnh 3.62, l c tuyn in p ngc theo in dung ca mt varactor. Hy xc nh thay i theo in dung nu VR thay i t 5V n 20V.

88. Hy xt c tuyn hnh 3.62, v xc nh gi tr ca VR c in dung 25pF.

89. Gi tr in dung cn thit cho mi varactor mch hnh 3.63, l bao nhiu to ra tn s cng hng l 1MHz?

90. Ti gi tr no cn phi c in p VR cho bi tp 89 nu varactor c c tuyn nh hnh 3.62?

Mc 1-20 Diode pht quang - LED

91. LED hnh 3.64(a) c c tuyn pht quang nh hnh 3.64(b). B qua st p thun ca LED, hy xc nh mc cng sut pht x (nh sng) c to ra theo mW.

92. Hy xc nh cch mc b hin th

by on hnh 3.65, hin th s 5. Dng thun lin tc ln nht cho mi LED l 30mA v s dng ngun cung cp l + 5V.

93. Lp rp mng n-giao thng vi LED mu vng bng cch dng s lng ti thiu cc in tr hn dng lm vic t ngun cung

cp l 24 V v bao gm 100 LED c F 30 mAI v s lng cc

LED bng nhau trong mi nhnh song song. Hy th hin mch v gi tr cc in tr.

94. Vi mt photodiode ti mc chiu sng cho, in tr ngc l

200k v in p ngc l 10V. Dng chy qua photodiode l bao nhiu?

-30-

95. in tr ca mi photodiode hnh 3.66, l bao nhiu?

96. Khi ng chuyn

mch hnh 3.67, microammeter ch th tng hay gim? Gi s D1 v D2 c ghp quang.

Mc 1-21 Cc loi diode khc

97. c tuyn V-I ca mt diode tunnel cho thy l dng in thay i t 0,25mA n 0,15mA khi in p thay i t 125mV n 200mV. in tr l bao nhiu?

98. Kiu mch no thng hay s dng diode tunnel?

99. Mc ch lm lch b mt no c trong s dng diode laser? Ti sao ch lm lch ring mt pha?

Mc 1-22 S c trong mch diode 100. i vi mi nhm cc mc in p o c ti cc im (1, 2, v 3) ghi hnh 3.68, xc nh

mch c hot ng ng chc nng hay khng, nhn dng cc h hng c th xy ra nht. Zener c thng s 12V. (a) V1 = 110V rms; V2 = 30V dc; V3 = 12V dc.

(b) V1 = 100V rms; V2 = 30V dc; V3 = 30V dc.

(c) V1 = 0V; V2 = 0V; V3 = 0V dc.

(d) V1 = 110V rms; V2 = 30V nh ton k 120Hz; V3 = 12V dc in p xung 120Hz.. (e) V1 = 110V rms; V2 = 9V; V3 = 0V.

101. in p u ra ca mch hnh 3.68, l bao nhiu xt theo mi trng hp hng sau y?. (a) D5 h mch. (b) R h mch. (c) C b r. (d) C h mch. (e) D3 h mch. (f) D2 h mch (g) T h mch. (h) F h mch.

-31-

102. Mt h thng tnh ton & iu khin c lp t ti nh ca khch hng. H thng ang c biu hin hot ng chp chn nn cn phi kim tra trc tin l bng mch ngun cung cp & thu / pht hng ngoi. Cn c vo hnh 3.69, hy xc nh xem b ngun c vn sai hng no khng.

103. Mt vn khc c h thng tnh ton & iu khin. Lc ny, h thng ngng hot ng hon ton v bn li quyt nh kim tra trc tin bng mch ngun cung cp. Cn c vo thng tin hnh 3.70, hy xc nh sai hng.

104. Lit k cc nguyn nhn c th c lm cho LED hnh 3.55 khng pht tia hng ngoi khi ngun cung cp c ni vi ngun in li.

-32-

105. Lit k cc nguyn nhn c th c lm cho photodiode hnh 3.55, khng p ng vi tia hng ngoi pht ra t LED. Nu cc bc theo trnh t c th c lp sai hng.

BI TP V THNG S CA DIODE 106. Tham kho trang s liu ca diode zener hnh 3.7.

(a) tiu tn cng sut dc ln nht ca diode 1N4738 ti 25C l bao nhiu?. (b) Xc nh tiu tn cng sut ln nht ca diode 1N4751 ti 70C v 100C?.

(c) Mc dng nh nht ca 1N4738 cn cho s n nh l bao nhiu?. (d) Mc dng ln nht ca 1N4750 ti 25C l bao nhiu?. (e) Dng chy qua 1N4750 thay i t 25mA n 0,25mA.

Tr khng zener cn phi thay i nh th no?

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(f) in p zener ln nht ca 1N4736 ti 50C l bao nhiu?

(g) in p zener nh nht ca 1N4747 ti 75C l bao nhiu?.

107. Tham kho trang s liu ca diode bin dung hnh 3.22. (a) in p ngc ln nht ca diode 1N5139 l bao nhiu?. (b) Xc nh tiu tn cng sut ln nht ca diode 1N5141 ti nhit mi trng l 60C?

(c) Xc nh tiu tn cng sut ln nht ca diode 1N5148 ti nhit v l 80C?. (d) Ti mc in p ngc 20V in dung ca 1N5148 l bao nhiu? (e) Nu ch ly theo tiu chun h s phm cht, th cn phi chn diode bin dung no? (f) in dung in hnh ca 1N5142 l bao nhiu ti VR = 60V?

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108. Tham kho trang s liu ca diode pht quang - LED hnh 3.31.

(a) C th t 9V theo chiu phn cc ngc ngang qua mt MLED81 c khng? (b) Xc nh tr s nh nht ca in tr ni tip vi MLED81 khi s dng in p 5,1V phn

cc thun cho diode? (c) Gi s mc dng thun l 50mA v st p thun l 1,5V lm vic nhit xung quang

45C. C vt qu thng s cng sut ln nht khng?. (d) Xc nh cng bc x theo mc dng thun l 30mA.

(e) Cng bc x ti gc 20 tnh t trc l bao nhiu nu dng thun l 100mA?

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109. Tham kho trang s liu ca photodiode hnh 3.36.

(a) Mt MRD82 c mc ni tip vi mt in tr 10k v ngun in p phn cc ngc. Khng chiu sng vo diode. St p trn in tr l bao nhiu?.

(b) Ti bc sng no s c mc dng ngc ln nht theo chiu sng cho?.

(c) Mc dng ti l bao nhiu ti nhit mi trng l 60C?. (d) Ti bc sng no nhy ca MRD821 mc ln nht?. (e) Nu nhy ln nht l 50A / mW / cm2 , th nhy ti 900nm l bao nhiu? (f) Tia hng ngoi vi bc sng l 900nm chiu vo MRD821 vi mc chiu sng l

3mW /cm2 v gc chiu l 40 t trc ln nht. Xc nh mc dng ngc.

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BI TP NNG CAO

110. Kho st s ca bng mch hnh 3.71, v xc nh kiu mch l mch g?

111. Nu in p vo 110V rms; 60Hz c ni n cc u vo ac, hy xc nh cc mc in p u ra trn bng mch hnh 3.71.

112. Nu mi u ra ca bng mch hnh 3.71, c

mc ti c 1,0k, thng s nh mc cn phi c s dng l bao nhiu?

113. Hy thit k b n nh in p bng zener m bo cc thng s sau: in p u vo l 24V dc, dng ti l 35mA, v in p trn ti l 8,2V.

BI TP B SUNG PHN DIODE

114. Mt diode silicon dn nhit 25C mc st p trn hai cc diode l 0,7V. Xc nh mc st

p V trn diode nu diode lm vic nhit +100oC v 100oC.

[p s: o o(100 C) = 0,55 V; (- 100 C) = 0,95 VV V ]

115. Mch hnh 1.31, dng chnh lu sng sin c 100Vrms v tn s 60Hz. Mc in p ra nh nht khng th gim di 70V v t s bin p l 1:2. in tr ti l 2k. Tnh in dung cn thit ca t lc mc song song vi RL. [p s: 8,25 F ]

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116. in p ra ca b chnh lu bn k vo khong 50V, tn s 60Hz. Gi s tr thun ca diode

bng 0, ti thp nht c th mc vo mch khi s dng t khong 50F duy tr mc in p

gn nh nht trn 40V l bao nhiu?

[p s: 1,67 k ]

117. Mch chnh lu ton k nh mch hnh 1.31, c bin p

vi t s vng dy l 5:1.

(a) Tnh tr s in dung ca t cn duy tr mc in p nh nht khong 10V trn ti 100.

[p s: 233 F ] (b) Nu in p tn hiu vo phn (a) thay i trong

khong t 110V n 120Vrms, tn s 60Hz, th tr s in dung cn thit l bao nhiu? [p s: 233 F ]

118. Mt mch n nh bng diode Zener (hnh 1.37) c in p u vo thay i trong khong t 10V n 15V v mc dng ti thay i trong khong t 100mA n 500mA. (a) Tnh tr s ca Ri v IZmax, bit rng mch s dng diode zener

6V. [p s: 6,33 ; 1,32 A ]

(b) Hy tnh cng sut nh mc cho diode zener v in tr vo

(Ri). [p s: 7,92 W; 12,8 W ]

(c) Hy tnh tr s ca t cn thit nu mc ngun l u ra ca

mch nn bn k vi tn hiu vo l 60Hz. [p s: 4731 F ]

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119. V c tuyn ID theo VD cho mt diode

silicon nu dng bo ha ngc IS =

0,1A, s dng n = 1,5 i vi silicon. Xc nh mc in p chuyn sang dn ca diode.

120. V c tuyn ID theo VD cho mt diode germanium nu dng bo ha ngc IS = 0,01mA. Xc

nh mc in p chuyn sang dn cho diode (c tuyn c th v trn cng trc th nh c tuyn ca bi tp 1.4).

121. Nu ti u ra ca mt mch nn bn k l 10k, th tr s ca t cn phi c l bao nhiu c mc in p ra khng thay i qu 5%? in p vo l 100Vrms, 60Hz. Da vo hnh

P1.1. Suy ra dng sng ra.

[p s: = 33,4 FC ]

122. Thit k mt b ngun cung cp theo kiu mch nn bn k nhn tn hiu vo l 120Vrms, 60Hz v yu cu mc in p ra ln nht l 17V v thp nht l 12V. Ngun cung cp

s cung cp in p ngun cho mch in t cn mc dng khng i l 1A. Hy xc nh cu hnh mch, t s vng dy ca bin p, tr s ca t. Gi s cc diode v bin p l l tng.

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123. Nu ti u ra ca mch nn ton k l 10k, tr s ca t l bao nhiu cn thit duy tr mc in p ra khng thay i thp nhiu so vi 10% ? Tn hiu vo l 110Vrms, 60Hz. Da vo hnh P1.3. V dng

sng ra.

124. Lp li bi tp 1.10, vi kiu ngun cung cp l mch chnh lu ton k.

[p s: 5; 12 ; 2,36 mFLa= R = ]

125. Hy xc nh thng s ca t trong mch hnh 1.31, khi a

= 6 v RL = 50. Mc in p nh nht n ti cn phi c

mc suy gim khng qu 20%.

127. Nu mt diode zener c mc trong mch nh hnh P1.6, tr s in tr Ri l bao nhiu duy tr in p trn ti mc 10V (VZ) khi dng ti

thay i t 50mA n 500mA v in p vo thay i t 15V n 20V ? Hy xc nh mc cng sut nh mc cn thit cho in tr v diode zener.

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128. Mch n nh bng zener nh hnh P1.6, s dng diode zener 20V duy tr in p khng i 20V trn in tr ti RL. Nu in p vo

thay i t 32V n 43V v dng ti bin thin t 200mA n 400mA, hy tnh chn tr s ca Ri gi in p khng i trn ti. Xc nh

cng sut nh mc cn thit cho in tr v diode zener.

129. Mch n nh zener nh hnh P1.7, s dng diode zener 9V gi mc in p khng i 9V trn ti, vi in p vo thay i t 18V n 25V v dng ra thay i t 400mA n 800mA. Gi s RZ = 0.

(a) Chn tr s cn thit cho Ri v xc nh mc cng sut yu cu nh

nht ca in tr vo. (b) Xc nh mc cng sut nh mc ca diode zener.

(c) Tnh bin thin ca in p ra nh nh nu RZ = 1.

[p s: 9,76 iR = ]

130. Gi s khng c tn hao trong cc diode nn ca mch nn ton k (hnh P1.8) vi n = 2, tr s ca Ri cn thit l bao nhiu duy tr VL mc

16V vi dng ti l 500mA, s dng zener 16V? VS thay i trong khong t 110Vrms n 120Vrms,

60Hz. Gi s RZ = 0. Mc in p mch n nh

cn phi khng c gim nhiu hn 8V trn mc VZ.

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131. Gi s khng c st p cc diode chnh lu trong mch hnh P1.8, v n = 2, tr s ca Ri cn thit l

bao nhiu duy tr VL = 16V vi mc dng ti

khong 500mA? in p vo ca bin p l 110Vrms n 120Vrms, 60Hz. in p ra ca mch nn c lc khng th thay i nhiu hn 5V. Hy xc nh cng sut nh mc cn thit cho in tr v diode zener.

132. Thit k b ngun n p ton k s dng bin p im gia 4:1 v diode zener 8V, 1W cung

cp 8V khng i cho ti thay i t 200 n 500. in p vo ca bin p l 120Vrms, 60Hz. B qua tn hao trong bin p v cc diode. Xc nh:

(a) IZmax v Izmin ; (b) Ri v Vsmin; (c) tr s t cn thit; (d) n nh theo % khi RZ = 2 .

[p s: max min125 mA; 93,7 ; = 12,9 V; 141 F;% Reg 2,81%Z i sI = R = V C = = ]

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133. Thit k b ngun n p ton k s dng bin p im gia 5:1 v diode zener 8V, 2W cung

cp 8V khng i cho ti thay i t 100 n 500. in p vo ca bin p l 120Vrms,

60Hz. B qua tn hao trong bin p v cc diode. Xc nh: (a) IZmax v IZmin. (b) Ri v VSmin. (c) tr s t cn thit.

(d) n nh theo % khi RZ = 2 . (e) Cng sut nh mc ca Ri.

134. S dng cc gi tr ca in p vo i vi Ri ca

bi tp 1.18, nhng dng zener 12V, tr s ca Ri cn phi c l bao nhiu duy tr 12V u ra nu ti thay i t 20mA n 600mA? Thng s ca t cn phi c l bao nhiu?

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135. S dng mch hnh P1.8, v gi s khng c tn

hao cc diode nn, tr s ca Ri l bao nhiu

duy tr 12V trn ti bng cch s dng diode zener 12V, khi VS t 105Vrms n 120Vrms, 60Hz? in

p ra ca mch nn gim 20% do thng s ca t C1, v ti thay i t 50mA n 500mA. Thng s ca t l bao nhiu? Cho n = 2.

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TM TT NI DUNG TRANSISTOR HIU NG TRNG JFETs

Tip gip pn cng-ngun cn phi c phn cc-ngc.

GSV iu khin DI .

Gi tr ca DSV m ti DI tr nn khng i

(bo ha) c gi l in p tht knh ( DSPV ) .

Gi tr ca GSV m ti DI tr nn bng 0 c

gi l in p ngt knh ( GS(off )V ) .

DSSI l gi tr dng mng khi GS 0V .

c tuyn truyn t:

2

GSD DSS

GS(off )

1V

I IV

h dn-thun:

GS0

GS(off )

1m mV

g gV

, trong : DSS

GS(off )

2m0

Ig

V

E-MOSFETs Ch lm vic ch tng cng

GSV cn phi ln hn GS(th)V .

Ch tng cng:

MOSFET tng cng knh n: GSV dng

MOSFET tng cng knh p: GSV m

GSV iu khin DI .

Gi tr ca GSV m ti DI bt u tng c gi l

in p ngng ( GS(th)V ) .

c tuyn truyn t: 2

D GS GS(th)2

kI V V

H s k c th tnh theo phng trnh trn bng cch thay th cc gi tr ca DI v GSV tng

ng vi D(on)I c quy nh theo GSV .

D-MOSFETs

C th lm vic c ch ngho hoc ch tng cng. GSV c th c phn cc ti

GS 0V

Ch ngho:

MOSFET ngho knh n: GSV m

MOSFET ngho knh p: GSV dng

Ch tng cng:

MOSFET tng cng knh n: GSV dng

MOSFET tng cng knh p: GSV m

GSV iu khin DI .

Gi tr ca GSV m ti DI tr nn bng 0 c gi l

in p ngt ( GS(off )V ) .

c tuyn truyn t: 2

D GS GS(th)2

kI V V

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IGBT c iu khin bng in p nh MOSFET.

H c tuyn ra ging nh BJT.

C ba in cc: cng, collector, emitter.

PHN CC CHO FET (Cc tnh in p v chiu dng in l o ngc i vi FET knh p)

2-1. Transistor hiu ng trng l cu kin n ht ti (ch mt loi ht ti in). Cc in cc ca FET l in cc ngun [Source], cc mng [Drain], v cc cng [Gate]. JFET lm vic vi tip gip pn (cng-ngun) phi c phn cc-ngc. in tr vo cao ca JFET l do tip gip pn (cng-ngun) c phn cc-ngc. Phn cc ngc JFET s lm cho vng ngho tng trong phm vi knh dn, do vy lm tng

in tr knh dn.

2-2. i vi JFET knh-n, GSV c th thay i t 0, m cho n in p ngng dn, GS(off )V . i vi

JFET knh-p, GSV c th thay i t 0, dng cho n in p ngng dn, GS(off )V .

DSSI l dng mng hng khi GS 0V . iu ny l ng cho c JFET v D-MOSFET .

FET c gi l cu kin theo lut-bnh phng do quan h gia DI theo bnh phng ca

biu thc gm c GSV .

2-3. Phn cc im gia ca mt JFET l D DSS 2I I , nhn c bng cch thit lp

GS GS(off ) 3,4V V

im-Q mch JFET phn cc phn-p l n nh hn so vi mch JFET t-phn cc. Phn cc ngun dng-hng s tng cng n nh ca mch JFET t-phn cc.

2-4. JFET s dng nh mt bin tr khi c phn cc lm vic vng thun tr [ohmic].

in p cng s iu khin DSR vng thun tr.

Khi JFET c phn cc ti gc h trc ta ( GS 0V , D 0I ), in tr knh dn ac s c

iu khin bi in p cng. 2-5. MOSFET khc vi JFET c im l cng ca MOSFET c cch ly khi knh bng mt

lp SiO2, khc vi cng v knh JFET c cch ly bi mt tip gip pn. MOSFET ngho (D-MOSFET) c th hot ng vi in p cng-ngun bng 0, dng, hoc

m.

D-MOSFET c knh vt l gia mng v ngun.

i vi D-MOSFET, cc gi tr m ca GSV s to ra ch ngho v gi tr dng ca GSV s

to ra ch tng cng. MOSFET tng cng khng c knh vt l. Khc vi JFET v D-MOSFET, E-MOSFET khng hot ng vi GS 0V .

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Knh dn c cm ng E-MOSFET bng cch t in p GSV ln hn so vi gi tr in

p ngng, GS(th)V . 2-6. E-MOSFET khng c thng s DSSI . Nu c th gi tr rt nh (l tng l bng 0).

E-MOSFET knh-n c GS(th)V dng. E-MOSFET knh-p c GS(th)V m.

c tuyn truyn t ca D-MOSFET giao ct vi trc dc DI .

c tuyn truyn t ca E-MOSFET khng giao ct vi trc dc DI .

Tt c cc cu kin MOS u d b hng do tnh in (ESD).

2-7. Phn cc im gia cho D-MOSFET l D DSSI I c c bng cch thit lp GS 0V .

D-MOSFET c cng c phn cc 0 do c in tr ln so vi t.

E-MOSFET cn phi c GSV ln hn so vi gi tr ngng.

2-8. BJT c cng cch ly (IGBT) l kt hp cc c tnh u vo ca MOSFET vi cc c tnh u ra ca BJT.

IGBT c ba in cc: emitter, cng, v collector. IGBT c s dng trong cc ng dng chuyn mch in p-cao.

2-9. H mch cng kh pht hin mch D-MOSFET phn cc-0 do in p cng thng mc 0 V, tuy nhin c th xut hin in p thay i.

H mch cng d pht hin mch E-MOSFET bi v in p cng thng khc vi 0 V. 2-10. in dn, mg , ca FET lin quan vi dng ra, DI , vi in p u vo, gsV .

H s khuych i in p ca mch khuych i ngun-chung (CS) c xc nh ch yu

bi in dn, mg , v in tr mng, dR .

in tr ni mng-ngun, dsr' ca FET s nh hng n h s khuych i (s lm gim h

s khuych i) nu n khng ln hn nhiu so vi dR c th b qua.

in tr gia cc ngun vi t ( sR )khng c r mch bng t s lm gim h s khuych

i in p ca b khuych i bng FET. in tr ti c mc n cc mng ca mch khuych i ngun-chung s lm gim h s

khuych i in p. C s o pha 180 cc in p gia cng v mng. in tr vo ti cng ca FET l rt cao.

2-11. H s khuych i ca mch khuych i mng-chung (CD) hay lp li-cc ngun (SF) lun lun nh hn 1.

mch SF khng c s o pha tn hiu gia cng v ngun.

2-12. in tr vo ca mch khuych i cng-chung (CG) bng nghch o ca mg .

Mch khuych i cascode l kt hp mch khuych i CS v CG. 2-13. Mch khuych i lp D l mch khuych i phi tuyn bi v cc transistor hot ng nh

cc chuyn mch. Mch khuych i lp D s dng iu ch bin -xung (PWM) biu din tn hiu vo. B lc thng-thp s chuyn i tn hiu PWM tr li thnh tn hiu vo ban u. Hiu sut ca b khuych i lp D s t n 100%.

2-14. MOS b (CMOS) c s dng trong cc mch chuyn mch s cng sut-thp. CMOS s s dng mt MOSFET knh-n v mt MOSFET knh-p mc ni tip vi nhau. B o, cng NAND, v cng NOR l cc v d ca mch logic s.

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Cu hi v transistor hiu ng trng

1. JFET l . . .

(a) cu kin n ht ti; (b) cu kin iu khin bng in p; (c) cu kin iu khin bng dng in; (d) gm c (a) v (c). (e) gm c (a) v (b).

2. Knh dn ca JFET l gia . . . (a) cng v mng; (b) mng v ngun; (c) cng v ngun; (d) u vo v u ra

3. JFET lun lm vic vi (a) phn cc ngc tip gip pn cng-ngun;(b) phn cc thun tip gip pn cng-ngun (c) in cc mng c ni t; (d) in cc cng c ni vi cc ngun.

4. Vi VGS = 0V, dng mng s tr nn khng i khi VDS vt qu (a) in p ngng dn; (b) VDD; (c) VDSP; (d) 0V

5. Vng dng-hng [constant-current] ca FET thuc trong khong gia (a) vng ngng dn v bo ha; (b) vng ngt v in p tht knh; (c) 0 v IDSS; (d) in p tht knh v in p nh thng.

6. IDSS l

(a) dng mng vi cc ngun b ngn mch;(b) dng mng ti vng ngt; (c) dng mng c th c ln nht; (d) dng mng im gia.

7. Dng mng vng dng-hng s tng ln khi (a) in p phn cc cng-ngun gim; (b) in p phn cc cng-ngun tng; (c) in p phn cc mng-ngun tng; (d) in p phn cc mng-ngun gim.

8. Trong mt mch FET c VGS = 0V; VDD = 15V; IDSS = 15mA, v RD = 470. Nu RD gim xung

bng 330, th IDSS bng (a) 19,5mA; (b) 10,5mA; (c) 15mA; (d) 1mA.

9. Ti vng ngt, knh dn ca JFET l (a) mc rng nht ca knh; (b) b nghn hon ton bi vng ngho; (c) rt hp; (d) c phn cc ngc.

10. Trang s liu ca JFET cho VGSOFF = - 4V. in p tht knh [pinch-off], VDSP, (a) khng th xc nh c; (b) = - 4V; (c) ph thuc vo VGS;(d) = + 4V.

11. JFET cu hi 10 (a) l JFET knh n; (b) l JFET knh p; (c) c th l c hai loi.

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12. Cho mt JFET c IGSS = 10nA o ti mc VGS = 10V. in tr vo l

(a) 100M; (b) 1M; (c) 1000M; (d) 1000m.

13. Mt JFET knh p, VGSOFF = 8V. Tr s ca VGS c phn cc im gia xp x bng (a) 4V; (b) = 0V; (c) 1,25V; (d) = 2,34V.

14. MOSFET khc bit chnh vi JFET l do (a) thng s cng sut; (b) MOSFET c hai cng; (c) JFET c mt tip gip pn; (d) cc MOSFET khng c knh vt l.

15. in tr mng-ngun vng thun tr ph thuc vo

(a) GSV ; (b) cc tr s ca im-Q;

(c) dc ca c tuyn ti im-Q; (d) tt c cc phng n trn.

16. s dng c nh mt bin tr, JFET cn phi (a) cu kin knh-n; (b) cu kin knh-p; (c) c phn cc vng thun tr; (d) c phn cc vng bo ha.

17. Khi JFET c phn cc gc h trc ta , in tr knh ac s c xc nh bng

(a) gi tr ca im-Q; (b) GSV ;

(c) h dn; (d) c (b) v (c).

18. MOSFET khc bit chnh vi JFET l do (a) thng s cng sut; (b) MOSFET c hai cng; (c) JFET c mt tip gip pn; (d) cc MOSFET khng c knh vt l.

19. Mt D-MOSFET (MOSFET-ngho) s hot ng (a) = 0A; (b) khng th xc nh c; (c) = IDSS;

20. Mt D-MOSFET knh-n vi VGS dng l ang lm vic (a) ch ngho; (b) ch tng cng; (c) ngt [cutoff]; (d) bo ha.

21. Mt E-MOSFET (MOSFET kiu tng cng) knh-p c VGS(th) = - 2V. Nu GS 0 VV , th dng

mng l

(a) 0A; (b) D(on)I ; (c) ln nht; (d) DSSI .

22. mt E-MOSFET khng c dng mng cho n khi GSV

(a) t n GS(th)V ; (b) dng; (c) m; (d) = 0.

23. Tt c cc cu kin MOS u d b hng do (a) qu nhit; (b) x in tch tnh; (c) qu p; (d) tt c cc l do trn .

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24. Mt D-MOSFET (MOSFET-ngho) c phn cc mc VGS = 0V. Cc thng s trang s liu

ca cu kin l DSS 20 mAI v GS(off ) = - 5 VV . Gi tr ca dng mng

(a) = 0A; (b) khng th xc nh c; (c) = 20 mA;

25. IGBT thng c s dng trong (a) cc ng dng cng sut-thp; (b) cc ng dng tn s cao (rf); (c) cc ng dng in p-cao; (d) cc ng dng dng-thp.

26. Trong mch khuych i ngun-chung (CS), in p ra l

(a) lch pha 180 so vi in p vo; (b) ng pha vi in p vo;(c) c ly trn cc ngun; (d) c ly trn cc mng; (e) gm c (a) v (c); (f) gm c (a) v (d).

27. Trong mch khuych i ngun-chung (CS), Vds = 3,2V rms v Vgs = 280mV rms. H s khuych i in p bng (a) 1; (b) 11,4; (c) 8,75; (d) 3,2

28. Trong mt mch khuych i CS, RD = 1k; RS = 0,56k; VDD = 10V, v gm = 4,5mS. Nu in tr ngun c r mch hon ton, th h s khuych i s bng (a) 450; (b) 45; (c) 4,5; (d) 2,52

29. Xt mt cch l tng, mch tng ng ca FET gm (a) 1 ngun dng mc ni tip vi 1 in tr; (b) 1 in tr gia cc mng v cc ngun; (c) 1 ngun dng gia cc cng v cc ngun; (d) 1 ngun dng gia cc mng v cc ngun

30. Gi tr ca ngun dng in cu hi 29 ph thuc vo (a) in dn v in p cng-ngun; (b) in p ngun cung cp; (c) in tr RD; (d) gm c (b) v (c).

31. Mt mch khuych i ngun-chung c h s khuych i in p bng 10. Nu tho t r mch cc ngun, (a) h s khuych i s tng; (b) h dn s tng; (c) h s khuych i s gim; (d) im-Q s b dch chuyn.

32. Mt mch khuych i CS c in tr ti bng 10k v RD = 0,8k. Nu gm = 5mS v Vin = 500mV, th in p tn hiu ra l (a) 1,89V; (b) 2,05V; (c) 25V; (d) 0,5V.

33. Nu loi b in tr ti mch cho cu hi 32, th in p tn hiu ra l (a) khng thay i; (b) gim; (c) tng; (d) bng 0.

34. Mt mch khuych i CD c RS = 1k c in dn l 6mS, h s khuych i l (a) 1; (b) 0,86; (c) 0,98; (d) 6.

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35. Trang s liu ca transistor s dng trong mch khuych i mng-chung (CD) cho IGSS = 5nA ti

mc VGS = 10V. Nu in tr mc gia cng v t, RG = 50M, in tr vo ton b xp x bng

(a) 50M; (b) 200M; (c) 40M; (d) 20,5M.

36. Mch khuych i cng-chung (CG) khc vi c hai cu hnh CS v CD c im l mch c (a) h s khuych i in p cao hn nhiu;(b) h s khuych i in p thp hn nhiu; (c) in tr vo cao hn nhiu; (d) in tr vo thp hn nhiu.

37. Nu yu cu c hai h s khuych i in p v in tr vo cao, th cn phi s dng (a) mch khuych i CS; (b) mch khuych i CD; (c) mch khuych i CG;

38. Mch khuych i cascode bao gm (a) mch khuych i CD v CS; (b) mch khuych i CS v CG; (c) mch khuych i CG v CD; (d) hai mch khuych i CG.

39. Mch khuych i lp D tng t vi (a) lp C; (b) lp B; (c) lp A; (d) ngoi cc trng hp trn.

40. Mch khuych i lp D s dng (a) iu ch tn s; (b) iu ch bin ; (c) iu ch rng-xung; (d) iu ch khng chu k.

41. E-MOSFET thng c dng cho cc ng dng chuyn mch l do . . . . . . . . ca chng

(a) c tnh ngng; (b) in tr vo cao; (c) tuyn tnh; (d) h s khuych i cao.

42. Mch ly mu cn phi ly mu tn hiu ti mc thp nht ca (a) mt khong thi gian trong chu k; (b) tn s tn hiu; (c) hai ln tn s tn hiu; (d) cc chu k thay i.

43. Mch CMOS c bn s dng t hp ca (a) cc MOSFET knh-n; (b) cc MOSFET knh-p;

(c) cc BJT pnp v npn; (d) mt MOSFET knh-n v mt MOSFET knh-p.

44. CMOS thng c s dng trong (a) cc mch s; (b) cc mch tuyn tnh; (c) cc mch RF; (d) cc mch cng sut.

45. Nu c mt h mch bn trong gia cc mng v cc ngun mch khuych i CS, th in p ti cc mng s bng vi

(a) 0V; (b) DDV ; (c) GSV ; (d) GDV .

-51-

BI TP

BI TP C BN

Mc 1-1 JFET

1. GSV ca mt JFET knh-p c tng ln t 1V n 3V.

(a) Vng ngho s hp hn hay rng hn? (b) in tr knh tng hay gim?

2. Ti sao in p cng-ngun ca JFET knh-n cn phi lun lun bng 0 hoc l m?

3. V k hiu mch ca JFET knh-p v knh-n. Ghi tn cc in cc.

4. Hy v cch mc in p phn cc gia cc cng v cc ngun ca hai JFET mch hnh 7.56.

Mc 2-2 H c tuyn v cc thng s ca JFET

5. Mt JFET c in p in p tht knh ( DSPV ) l 5V. Khi GS 0 VV , th DSV l bao nhiu ti im

m dng mng tr nn khng i?

6. Mt JFET knh-n c phn cc mc GS - 2 VV . Tr s ca GS(off )V l bao nhiu nu DSPV c

xc nh l 6V? Cu kin ang dn dn hay ngng dn?

7. Trang s liu ca mt JFET cho bit GS(off ) - 8 VV v DSS 10 mAI . Khi GS 0 VV , th DI l bao

nhiu i vi cc gi tr ca DSV ln hn in p tht? DD 15 VV .

8. Mt JFET knh-p c GS(off ) 6 VV . DI l bao nhiu khi GS 8 VV ?

9. JFET mch hnh 7.57, c GS(off ) - 4 VV . Gi s rng tng in p

ngun cung cp DDV bt u ti mc 0 cho n khi ammeter t

n tr s n nh. Voltmeter s ch th gi tr tng ng l bao nhiu?

-52-

10. Cc thng s sau t trang s liu ca

mt JFET: GS(off ) - 8 VV v

DSS 5 mAI . Hy xc nh cc tr s

ca DI theo mi tr s ca GSV trong

khong t 0V n 8V theo cc mc tng 1V. V c tuyn truyn t t s liu trn.

11. Vi JFET bi tp 10, gi tr no ca GSV cn thit lp mc dng mng l 2,25mA?

12. Vi JFET, c gm0 = 3200S. Gi tr ca gm l bao nhiu khi GS - 4 VV , bit rng GS(off ) - 8 VV ?

13. Xc nh h dn thun ca JFET c phn cc mc GS - 2 VV . Cc thng s t trang s

liu, GS(off ) - 7 VV v gm = 2000S o ti mc GS 0V . Ngoi ra, hy xc nh dn np

truyn t thun, yfs.

14. Trang s liu ca mt JFET knh-p cho bit GSS 5 nAI ti mc GS 10 VV . Xc nh in tr

vo ca JFET.

15. V c tuyn truyn t ca JFET c

DSS 8 mAI v

GS(off ) - 5 VV . S

dng t nht 4 im.

Mc 2-3 Phn cc cho JFET

16. Mt mch JFET knh-n t phn cc c mc dng mng l 12 mA v in tr mc ti cc ngun

l 100. Gi tr ca GS 0V tng ng l bao nhiu?

17. Hy xc nh tr s ca SR cn thit mch JFET t phn cc to ra GS - 4 VV khi dng mng

D 5 mAI .

18. Hy xc nh tr s ca SR cn thit mch JFET t phn cc to ra dng mng D 2,5 mAI khi

GS - 3 VV .

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19. Mt JFET c DSS 20 mAI v GS(off ) - 6 VV .

(a) Gi tr ca DI l bao nhiu khi GS 0V ?

(b) Gi tr ca DI l bao nhiu khi GS GS(off )V V ?

(c) Nu tng GSV t - 4V n

1V, th DI s tng ln hay

gim xung?

20. Hy xc nh DSV v GSV cho mi

mch hnh 7.58.

21. S dng c tuyn hnh 7.59, xc nh gi tr ca SR p

ng vi dng mng l 9,5mA.

22. Thit lp phn cc im gia cho JFET c DSS 14 mAI v

GS(off ) - 10 VV . S dng ngun cung cp 24V. Hy v

mch v tnh cc tr s cc in tr. Cng nh cc tr s ca

DI , GSV , v DSV .

23. Hy xc nh in tr vo ton b cho mch hnh 7.60.

Cho GSS 20 nAI tng ng vi GS 10 VV .

24. Xc nh im-Q bng th ca mch hnh 7.61(a) bng cch dng c tuyn truyn t hnh 7.61(b).

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25. Xc nh thng s im-Q cho mch JFET knh-p nh hnh 7.62.

26. in p o gia mng v t trong mch hnh 7.63 l 5V, hy xc nh thng s im-Q ca mch.

27. Xc nh cc gi tr ca in-Q ca mch JFET phn cc phn p hnh 7.64.

Mc 2-4 Vng thun tr [ohmic]

28. Mt JFET c phn cc vng thun tr ti mc DS 0,8 VV v D 0,20 mAI . Gi tr ca

in tr mng-ngun l bao nhiu?

29. im-Q ca mt JFET thay i t DS 0,4 VV v D 0,15 mAI n DS 0,6 VV v

D 0,45 mAI . Hy xc nh khong cc gi tr ca DSR .

30. Xc nh in dn ca JFET c phn cc ti gc ta bit rng m0 1,5 mSg ; GS - 1 VV ;

v GS(off ) - 3,5 VV .

31. Xc nh in tr mng-ngun ac ca JFET cho bi tp 30.

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Mc 2-5 MOSFET

32. V k hiu mch ca D-MOSFET v E-MOSFET knh-n v knh-p.

33. ch lm vic no D-MOSFET knh-n hot ng vi VGS dng.

34. Gii thch s khc nhau c bn gia D-MOSFET v E-MOSFET.

35. Gii thch ti sao c hai loi MOSFET u c in tr vo rt cao ti cng.

Mc 2-6 Cc thng s v h c tuyn ca MOSFET

36. Phiu s liu ca E-MOSFET cho bit l D(on) 10 mAI

ti mc GS - 12 VV v GS(th) - 3 VV . Tnh DI tng

ng vi GS - 6 VV .

37. Tnh IDSS, cho bit l, D 3 mAI ; GS - 2 VV , v

GS(th) - 10 VV .

38. Phiu s liu ca mt D-MOSFET cho bit GS(th) - 5 VV v DSS 8 mAI .

(a) Cu kin ny l knh-p hay knh-n?

(b) Xc nh mc dng DI theo cc gi tr ca GSV

trong khong t - 5V n + 5V theo bc tng

1V.

(d) V c tuyn truyn t bng cch s dng s liu t phn (b)

Mc 2-7 Phn cc cho MOSFET

39. Hy xc nh mi D-MOSFET mch hnh 7.65, l c phn cc ch no (ngho; tng cng; hay phn cc 0).

40. Mi E-MOSFET mch hnh 7.66, c GS(th)V

bng + 5V hoc 5V, ty thuc vo cu kin l knh-n hay knh-p. Hy xc nh tng MOSFET dn [ON] hay ngng dn [OFF].

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41. Hy xc nh DSV cho mi mch hnh 7.67, DSS 8 mAI .

42. Tnh GSV v DSV cho mi mch E-MOSFET hnh

7.68, Thng s c lit k mi mch.

43. Cn c vo cc gi tr o GSV t ng

h trn mch, hy xc nh mc dng mng v in p mng-ngun cho mi mch hnh 7.69.

44. Hy xc nh in p cng-ngun thc t

mch hnh 7.70, bng cch tnh t dng r cng, GSSI . Cho bit l GSSI

bng 50 pA v DI bng 1mA cc trng thi phn cc tng ng.

Mc 2-8 IGBT

45. Hy gii thch ti sao IGBT c in tr vo rt cao. 46. Hy gii thch dng collector tng vt tri nh th no to ra trng thi cht-ln [latch-up]

IGBT.

Mc 2-9 Mch khuych i ngun-chung (CS)

47. Mt JFET c gm = 6mS. Hy xc nh mc dng mng rms theo mi gi tr rms ca GSV sau.

(a) 10mA (b) 150mV (c) 0,6V (d) 1V

48. H s khuych i ca mch khuych i bng JFET vi in tr mc ti cc ngun bng 0 l 20. Hy xc nh in tr mng nu gm bng 3,5mS.

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49. Mt mch khuych i bng JFET c 4,2 mSmg ; DS 12 kr' v D 4,7 kR . H s khuych

i in p ca mch l bao nhiu? Gi thit in tr mc ti cc ngun l 0 ..

50. H s khuych i ca mch khuych i cho bi tp 3 l bao nhiu nu in tr mc ti cc ngun bng 1 k?

51. Nhn dng loi FET v mch phn cc ca FET hnh 8.33. GSV l bao

nhiu?

52. Tnh cc mc in p dc trn mi in cc so vi t ca cc FET hnh 8.33.

53. Nhn bit c tuyn hnh

8.34, tng ng vi loi FET no?

54. Tham kho c tuyn truyn t ca JFET hnh 8.18(a) v xc nh tr s nh-nh ca di khi

thay i trong khong 1,5V xung quang gi tr ca im - Q.

55. Lp li bi tp 8 vi cc c tuyn hnh 8.18(b) v hnh 8.18(c).

-58-

56. Mch hnh 8.35, c D 2,83 mAI , tnh DSV v GSV . Thng s ca

JFET l GS(off ) - 7 VV v DSS 8 mAI .

57. Nu a tn hiu vo 50 mV rms n mch khuych i hnh 8.35,

th mc in p ra nh-nh l bao nhiu? gm = 5 mS.

58. Nu ti 1,5 k c mc u ra ca mch hnh 8.35, th mc in p ra (rms) c trn ti l bao nhiu khi t tn hiu vo l 50 V rms? gm = 5 mS.

59. Hy xc nh h s khuych i in p cho mi mch hnh 8.36.

60. V mch tng ng dc v ac cho b khuych i hnh 8.37.

61. Xc nh mc dng mng trong mch hnh 8.37, JFET c

DSS 15 mAI v

GS(off ) - 4 VV . im-

Q c chn trung tm vng lm vic.

62. H s khuych i ca mch hnh 8.37, l bao nhiu nu C2 c tho ra khi mch.

63. Trong mch hnh 8.37, nu mc song song vi RL mt in tr 4,7k, th h s in p l bao nhiu?

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64. Vi mch khuych i ngun-chung (CS) hnh 8.38, hy xc nh DI , GSV v DSV c im-Q trung tm.

DSS 9 mAI , v GS(off ) - 3 VV .

65. Nu t tn hiu 10 mV rms vo u vo ca mch khuych i hnh 8.38, th gi tr hiu dng ca tn hiu ra l bao nhiu?

66. Hy xc nh GSV , DI , v DSV ca mch khuych i hnh 8.39.

D(on) 18 mAI o mc GS 10 VV ; GS(th) 2,5 VV , v gm = 3mS.

67. Hy xc nh inR nhn t ngun tn hiu vo mch hnh

8.40. GSS 25 nAI tng ng vi GS - 15 VV .

68. Hy xc nh dng sng in p ton b ti cc mng (dc v ac) v dng sng outV hnh 8.41. gm = 4,8 mS v

DSS 15 mAI .

69. Cho mch khuych i khng ti hnh 8.42, tnh GSV , DI ,

DSV , v in p ra hiu dng, DSv . Bit D(on) 8 mAI ti

GS 12 VV ; GS(th) 4 VV , v gm = 4,5mS.

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Mc 2-10 Mch khuych i mng chung CD

70. Cho mch lp li-ngun hay cn gi l SF [Source-Follower] hnh 8.43, tnh h s khuych i in p v

in tr vo ca mch. GSS 50 pAI ti GS - 15 VV ; v gm

= 5,5 mS.

71. Nu JFET trong mch hnh 8.43, c thay th bng mt JFET khc c gm = 3mS, th h s khuych i v in tr vo l bao nhiu? tt c cc iu kin khc trong mch khng thay i.

72. Tnh h s khuych i cho mi mch hnh 8.44.

73. Xc nh h s khuych i in p cho mi mch hnh 8.44, khi ti c thay i bng 10 k.

Mc 2-11 Mch khuych i cng chung CG

74. Mt mch cng chung c gm = 4mS v D 1,5 kR .

H s khuych i ca mch l bao nhiu?

75. in tr vo ca mch khuych i bi tp 74 l bao nhiu?

76. Hy xc nh h s khuych i in p v in tr vo ca mch khuych i cng chung hnh 8.45.

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77. Cho mch khuych i cascode nh th hin hnh 9.24, 2,8 mSmg ; GSS 2 nAI @ GS 15 VV . Nu

3 15 MR v 1,5 mHL , hy xc nh h s

khuych i in p v tr khng vo tn s

100 MHzf .

Mc 2-12 Mch khuych i lp D 78. Mch khuych i lp D c tn hiu ra l 9 V. Nu tn hiu vo l 5 mV, th h s khuych i l

bao nhiu ? 79. Mch khuych i lp D tiu tn cng sut l 140 mW b so snh v mch to sng tam gic.

Mi MOSFET h b c st p l 0,25 V trng thi dn [on]. Mch khuych i lm vic t hai

ngun 12 Vdc v cung cp 0,35 V n ti. Hy xc nh hiu sut. Mc 2-13 Chuyn mch tng t bng MOSFET 80. Mt chuyn mch tng t s dng MOSFET knh-n c GS(th) 4 VV . in p + 8 V c t n

cng. Hy xc nh tn hiu vo nh-nh ln nht c th p dng nu st p mng-ngun c b qua.

81. Chuyn mch tng t c s dng ly mu tn hiu c tn s ln nht l 15 kHz. Hy xc

nh tn s thp nht ca xung c p t vo cng ca MOSFET. 82. Mch t lm chuyn mch s dng t 10 pF. Hy xc nh tn s yu cu . . . 83. Vi tn s 25 kHz, in tr emulated l bao nhiu chuyn mch t nu 0,001 FC .

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Mc 2-14 Chuyn mch s bng MOSFET 84. in p u ra ca b o bng CMOS l bao nhiu lm vic vi DD 5 VV , khi tn hiu u

vo l 0 V? Khi tn hiu vo + 5 V? 85. i vi mi t hp tn hiu vo sau y, xc nh tn hiu ra cng NAND bng CMOS hot

ng vi DD 3,3 VV

(a) A 0 VV ; B 0 VV

(b) A 3,3 VV ; B 0 VV

(c) A 0 VV ; B 3,3 VV

(d) A 3,3 VV ; B 3,3 VV

86. i vi mi t hp tn hiu vo sau y, xc nh tn hiu ra cng NOR bng CMOS hot ng

vi DD 3,3 VV

(a) A 0 VV ; B 0 VV

(b) A 3,3 VV ; B 0 VV

(c) A 0 VV ; B 3,3 VV

(d) A 3,3 VV ; B 3,3 VV 87. Lit k hai u im ca chuyn mch cng sut bng MOSFET so vi bng BJT. Mc 2-15 Sai hng mch FET

88. Mc dng ch th trn ng h o hnh 7.58(a) gim t ngt v 0. Sai hng c th c l nh th no?

89. Mc dng ch th trn ng h hnh 7.58(b) tng t bin ln 16mA. Sai hng c th c l g?

90. Nu in p ngun cung cp mch hnh 7.58(c) ngu nhin b thay i ln mc 20V, th s ch th trn ammeter l bao nhiu?

91. in p o ti cc mng ca MOSFET mch hnh 7.66(a) l + 10V. o th transistor cho thy bnh thng v cc kt ni t tt. Nguyn nhn no c th gy ra s o trn?

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92. in p o ti cc mng ca MOSFET mch hnh 7.66(b) l 0V. Mch khng c cc ngn mch v o th transistor cho thy tt. Nguyn nhn no c th d xy ra nhiu nht vi s o trn?

93. Hy cho bit cc du hiu c th c no mi sai hng sau khi in p tn hiu c t vo mch hnh 8.46?

(a) Q1 h mch t cc mng n cc ngun.

(b) 3R h mch (c) 2C b ngn mch (d) 3C h mch (e) Q2 h mch t cc mng n cc ngun.

94. Nu 10 mV rmsinv mch hnh 8.46, th outv s l bao nhiu tng ng vi cc h hng no sau y? (a) 1C h mch (b) 4C h mch (c) mt ngn mch t cc ngun ca Q2 vi t (d) Q2 c mt in cc b h mch

BI TP NG DNG H THNG

95. Tham kho hnh 8.58, v xc nh in p ca sensor theo mi gi tr ca pH sau y

(a) 2

(b) 5

(c) 7

(d) 11

96. Da vo h c tuyn truyn t ca BF998 hnh 8.79, hy xc nh thay i DI khi in

p phn cc cng 2 c thay i t 6 V xung 1 V, v G1SV l 0 V. Mi c tuyn tng ng

vi mt gi tr G2SV .

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97. Xt mch hnh 8.61, v v c tuyn truyn t ( DI theo

G1SV ).

98. Tham kho hnh 8.79. Hy xc nh in p ra ca mch hnh 8.61, nu G1S Sensor 0 VV V v 2R

c thay i v mc 50 k .

99. t in p 100mVrms c tn

s 1kHz vo im o s 1 hnh 8.47. Ti im o s 5 o c in p dc l 6,75V, nhng khng c in p ac ti im o ny. Hy xc nh li duy nht trong mch.

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100. Gi thit li bi tp 99 ca mch hnh 8.47, c khc phc v in p tn hiu vo c tng ln mc 250 mV rms. Nu cc in p sau y l c o ti cc im o th quy nh, hy xc nh li c th c v tnh trng hng cn phi tin hnh sa cha mch l g? im o th s 2: 250 mV rms

im o th s 3: 800 mV rms

im o th s 4: 530 mV rms

im o th s 5: 2,12 V rms

101. Gi thit cc li trn y tromg mch hnh 8.47, c khc phc. Hy xc nh cc mc in p dc v ac s phi o c ti im o s 5 nu transistor ca tng th nht c DSS 2,85 mAI

v gm = 2.2 mS v transistor ca tng th 2 c DSS 5,10 mAI v gm = 2,6mS. Tn hiu vo l

100 mV rms.

BI TP V THNG S CA FET

102. FET c s hiu 2N5457 l loi cu kin g?

103. Tham kho phiu s liu hnh 7.14, xc nh cc thng s sau:

(a) GS(off )V thp nht ca 2N5457.

(b) in p mng-ngun ln nht ca 2N5457.

(c) Mc tiu tn cng sut ln nht ca 2N5457 ti nhit mi trng l 25C.

(d) in p ngc cng-ngun ln nht ca 2N5458.

104. Tham kho phiu s liu hnh 7.14, xc nh mc tiu tn cng sut ln nht ca 2N5457 nhit mi trng 65C.

105. Tham kho phiu s liu hnh 7.14, xc nh gm0 ca 2N5457 ti tn s 1kHz.

106. Tham kho phiu s liu hnh 7.14, mc dng mng in hnh ca 2N5457 khi GS 0 VV l bao

nhiu? .

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107. Tham kho phiu s liu hnh 7.41, hy xc nh in p cng-ngun thp nht m MOSFET bt u dn dng? .

108. Tham kho phiu s liu hnh 7.41, mc dng mng l bao nhiu khi GS 10 VV ?

109. Tham kho phiu s liu hnh 7.52, xc nh dng mng ID chy trong 2N3797 khi GS + 3 VV

Tnh DI tng ng vi GS - 2 VV .

-67-

110. Tham kho phiu s liu hnh 7.52, h dn thun ln nht ca 2N3796 thay i trn khong tn s tn hiu t 1kHz n 1MHz l bao nhiu?

111. Tham kho phiu s liu hnh 7.52, hy xc nh gi tr in hnh ca in p cng-ngun tng ng khi 2N3796 chuyn sang ngng dn.

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112. FET c s hiu 2N3796 l FET kiu g? 113. Tham kho phiu s liu hnh 8.30, xc nh cc thng s sau:

(a) VGS(off) in hnh ca 2N3796.

(b) in p mng-ngun ln nht ca 2N3797

(c) Mc tiu tn cng sut ln nht ca 2N3797 ti nhit mi trng l 25C

(d) in p cng-ngun ln nht ca 2N3797

114. Tham kho phiu s liu hnh 8.30, xc nh mc tiu tn cng sut ln nht ca 2N3796 ti nhit mi trng l 55C.

115. Tham kho phiu s liu hnh 8.30, xc nh gm0 nh nht ca 2N3796 ti tn s l 1kHz.

116. Dng mng ca 2N3797 l bao nhiu khi GS +3,5 VV ?

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117. Dng mng c trng ca 2N3796 l bao nhiu khi c phn cc 0? 118. H s khuych i in p c th c ln nht ca mch khuych i ngun-chung bng 2N3796 l

bao nhiu vi D 2,2 kR ?

BI TP NNG CAO

119. Tnh DSV v GSV trong mch hnh 7.71, bng cch s dng cc gi tr nh

nht ca cc thng s cn thit cho phiu s liu.

120. Tnh DI v GSV trong mch hnh 7.72.

121. Xc nh khong cc gi tr im-Q c th c t nh nht n ln nht cho mch hnh 7.71.

122. Tnh in p mng-ngun cho cc mch cm bin pH hnh 8.59, khi pH o c bng 5. Gi s cc bin tr l c thit lp to ra mc 4 V ti cc cc mng khi pH c o bng 7.

123. Thit k mch MOSFET vi phn cc 0, s dng 2N3797 hot ng bng ngun cung cp + 9V dc to ra DSV bng 4,5V. Dng mng ln nht chy t ngun l 1mA.

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124. Thit k mch bng E-MOSFET vi cc thng s phiu s liu nh sau: DS(on) 500 mAI @

GS 10 VV v GS(th) 1 VV . S dng ngun cung cp dc +12V, vi phn cc phn p to ra

in p + 8V ti cc mng v dng ln nht t ngun cung cp l 20mA.

125. MOSFET trong mt mch khuych i ngun-chung, n tng c khong cc gi tr h dn thun t 2,5 mS n 7,5 mS. Nu mch khuych i ghp tng bng t vi ti c th thay i

c trong khong t 4 k n 10 k v in tr mng dc l 1,0 k, hy xc nh cc h s khuych i nh nht v ln nht.

126. Thit k mch khuych i s dng 2N3797 lm vic vi ngun cung cp l 24 V. in p mng-ngun dc in hnh cn phi xp x 12 V v h s khuych i in p in hnh cn phi vo khong bng 9.

127. Sa i li mch c thit k bi tp 126, c h s khuych i in p c th thit lp mc bng 9 cho bt k transistor 2N3797 no c la chn mt cch ngu nhin.

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BI TP B SUNG PHN FET

128. Thit k mch khuych i chung cc ngun-Common Source (CS) bng JFET c RL =

10k, VDD = 12V, Rin = 500k, v Av = - 2. S dng mch hnh 4.16a. Chn im-Q l VDSQ =

6V, VGSQ = - 1V, IDQ = 1mA, v gm = 2500S.

[p s: 1 2= 4,78 k; =1,22 k; = 509 k; = 27 M;& - 100D S iR R R R A ]

129. Thit k li mch khuych i CS bng JFET bi tp 128, nu dng transistor c VGSoff = - 4V

v IDSS = 6mA.

[p s: 1 2 dc ac= 500 k; = ; =1,61 k; = 390 ; = 223 ;& - 100D S S iR R R R R A ]

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130. Thit k mch khuych i CD bng JFET (hnh 4.19) cho h s khuych i dng in bng

15 cho ti l RL = 20k s dng VDD = 12V v Rin = 400k. S dng JFET knh-n c

VGSoff = - 3V, v IDSS = 6mA. Gi s VDSQ = VDD/2 v IDQ = 0,4IDSS. Tnh tr s ca cc in tr

v h s khuych i in p ca mch khuych i.

[p s: dc ac 1 2= 2,5 k; =1,25 k; = 676 k; = 980 k;& 0,75S S iR R R R A ]

131. Xc nh tr s ca cc in tr v h s khuych i dng in cho mch khuych i bootstrap bng JFET kiu SF theo cc yu cu

l Rin = 200k, RL = 20k, v VDD = 10V. im- Q c chn

ti: VDSQ = 5V, IDQ = 0,5mA, VGSQ = - 1,5V, gm = 4mS. S dng

mch hnh 4.21.

[p s: G 1 2= 62,8 k; = 3 k; = 7 k; 9,3S S iR R R A ]

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132. Cho mch hnh P4.1a, vi JFET knh-n c th c cc thng s xp x bng phng trnh:

iD = 0,5(4 + vGS)2 mA

v RS = 500, RD = 2k, Rin = 100k, IDQ = 5mA, v VDD = 20V. Hy xc nh cc thng s

ca mch sau: (a) VGSQ; (b) VD ; (c) VDSQ; (d) R1 v R2.

[p s: 1 2 dc(a) - 0,84 V; (b) 10 V; (c) 7,5 V; = 109 k; =1,2 M; = 390 SR R R ]

133. Trong mch hnh 4.16a, khi c R1 = 21k, R2 = 450k, RS =

500, RD = 1,5k, RL = 4k, v VDD = 12V, khi VDSQ = 4V, hy

xc nh cc thng s sau y: (a) IDQ; (b) VGSQ; (c) Rin; (d) Av khi gm = 3,16mS; (e) Ai.

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134. Trong mch hnh 4.16a, RD = 2k, RL = 5k, Rin = 100k, RS =

300, v VDD = 15V. Xc nh cc tr s ca R1 v R2 cn thit

transistor lm vic mc 4mA khi VGSoff = - 4V v IDSS = 8mA. Tnh h s khuych i in p v dng in ca mch khuych i.

135. (a) Thit k mch khuych i chung cc ngun [Common-Source tc CS] (hnh P4.1) s dng JFET knh-p p ng cc thng s yu

cu l Av = - 10 v Rin = 20k.

Gi thit l im-Q c chn ti IDQ = - 1mA, VDSQ = -10V, VGSQ = 0,5V.

(b) Tnh Ai, R1, R2, RS, v RD. (Da

vo c tuyn hnh P4.2. Lu rng c th c chia tch RS v

mch r cho RS).

[p s: c dc 2= 338 ; = 500 ; = 9,5 k; - 21,1; =

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