TRNG I HC

CNG NGHIP THC PHM

TIU LUN MN IN T C BN

Ch : Linh kin Opto

I. CU TO:

Trong in-in t, opto cn gi l b cch

ly quang (opto-isolator), l mt linh kin

dng truyn tn hiu in bng cch

chuyn tn hiu sang nh sng v sau mi

truyn i.

Cu to ca opto gm mt LED pht v

mt LED thu l photo diot hay photo

transitor, c hai c tch hp nm bn

trong mt v bc kn.

II. K HIU:

Trn mch nguyn l n c k hiu nh

sau :

Cch b tr LED pht v LED thu bn trong ca opto-coupler:

III. NGUYN L HOT

NG:

Khi c dng nh i qua 2 u ca

led c trong opto lm cho LED pht

sng. Khi LED pht sng lm thng

hai cc ca photo transitor hay photo

diot m cho dng in chy qua.

IV. C TUYN VOLT AMPE:

c tuyn v-i ca LED:

c tuyn volt ampe ca LED tng t c

tuyn volt ampe ca diode thng: n biu

din mi quan h gia dng in quang vi in

p t ln LED.

Nhng khong mc ngng cho php ca LED

ty loi LED v mc ngng ny ln hn mc

ngng ca diode thng. in p nghch ti

a ca LED tng i thp.

c tuyn v-i ca Photo diode :

c tuyn V-I ca quang diod vi quang

thng l thng s cho thy quang thng nh

khi in th phn cc nghch nh, dng in

tng theo in th phn cc,nhng khi in

th phn cc ln hn vi volt, dng in gn

nh bo ha (khng i khi in th phn

cc nghch tng).

Khi quang thng ln, dng in thay

i theo in th phn cc nghch.

Tn s hot ng ca quang diode c

th ln n hnh MHz. Quang diode

cng nh quang in tr thng

c dng trong cc mch iu

khin ng - m mch in (dn

in khi c nh sng chiu vo v

ngng khi ti).

c tuyn v-i ca photo transistor

V. KIM TRA H HNG:

S dng ng h o VOM kim tra h

hng cho OPTO :

Cho hai que th chn vo Anode(chn s 1)

cn chn en vo Kathode(chn s 2 )ca

DIODE trong OPTO v o nh mt diode bnh

thng chn 1 v 2 dn th 3 v 4 cng

dn.Chn 3 v 4 chnh l chn CE ca

transistor loi NPN, ta thang o X10K ri

o, Kim nhch ln mt t, tm s 100 n 150

l tt, khng ln l t, ln gn v cng l b

r CE, ln ht n 0 l b chp CE.

VI. Hnh dng Opto: Bn di l cc hnh dng thc t ca opto v

ng dng ca n trong in-in t cng

nghip:

Cc Opto thng dng hin nay:

a. Opto P521:

L linh kin 4 chn v c k hiu

Cch xc nh chn ca opto 521:

Chn 1 l gn du chm trn mt opto ( du chm

nh lm xung), gn chn 1 l chn 2, i din

chn 1 l chn 3, bn chn 3 l chn 4.

Trong :

1 l Anode

2 l Cathode

3 l Emitter (b pht)

4 collector (b thu)

Opto 521-2:

L kinh kin 8 chn:

b. Cch xc nh chn ca P521-2 tng t nh

P521

Trong :

1, 3 l Anode

2, 4 l Cathode

5, 7 l Emitter

6, 8 l Collector

c. Ngoi ra cn c P521-4:

Xc nh tng t nh P521, P521-2. V c 16

chn.

1,3,5,7 l Anode

2,4,6,8 l Cathode

9,11,13,15 l Emitter

10,12,14,16 l Collector

d. Opto 4N35:

l linh kin c 6 chn, cch xc nh chn tng t nh P521

1 l Anode

2 l Cathode

3 l NC

4 l Emitter

5 l Collector

6 l Base

V. ng dng:

OKhi s c t tng ng dng

nh chy, chp, tng p,...th

cng khng lm nh hng

n tng iu khin