76216663 Bach Khoa Tp Hcm

BO CO TH NGHIM O IN T

BI 1: Volt k

Phn 1 : Volt k DC.

Xc nh ni tr khung quay :

1. Phng php bin tr:

a. S mch th nghim :

b. Bng gi tr cc ln o :

Ln o R1-Lch ton khung R2-Lch na khung Rm1=R2-2R1 Gi tr tr 13.68K 31.2k 3.84k

2. Phng php chia th :

a. S mch th nghim :

b. Bng gi tr cc ln o :

i Lng E (mV) I(uA) Rm2 255 50 5.1k

3. Phng php in tr Shunt :

a. S mch th nghim :

b. Bng cc gi tr o :

Bin tr R50k R100k Rm3

Gi tr 1.02k 11.3k 3.6k

4. Gi tr trung bnh ni tr ca khung quay t cc ln o trn :

RmTB =4.18K=R1 5. Chn in tr phn tm o cho Volt k :

Tm o chung :

V1= ( R1 +Rm) Ifs V2=( R1+R2 +Rm) Ifs V2=( R1+R2 +R3+ Rm) Ifs

R1 , R2, R3.

Tm o c lp

Rtd =

Rmtb R2=15.8K R3=95.8K R4=195.8K

Tm o

in tr RS

Tr s in tr tng ng cc

lch

Sai s tng i % ( TB cng)

25%

50%

75%

100%

0-1V 15.8K E1 0.194 0.416 0.621 0.831

=18.325%

E2 0.25 0.5 0.75 1

0-5V 95.8K E1 1.05 2.1 3.2 4.2

=15.675%

E2 1.25 2.5 3.75 5

0-10V 195.8K E1 2.36 4.83 7.21 9.65

=4.1%

E2 2.5 5 7.5 10

Phn 2 : Volt k AC. Tnh ton nhy xoay chiu ca khung quay

Tnh ton cc gi tr in tr tm o cho cc tm o tr hu dng in p xoay chiu 5V 10V 20V mch

o.

Lp rp Volt k xoay chiu chnh lu bn k nh hnh 4

Tnh ton nhy xoay chiu ca khung quay

Tnh ton cc gi tr in tr tm o cho cc tm o tr hu dng in p xoay chiu 5V 10V 20V mch

o.

Lp rp Volt k xoay chiu chnh lu ton k nh hnh 5

Bng s liu :

Chnh lu bn sng Chnh lu ton sng

nhy xoay chiu nhy xoay chiu

Tm o Tnh ton o c Sai s Tm o Tnh ton o c Sai s

5 39K 40.4K 3.5% 5 60K 73K 21.67%

10 84.5K 88.3K 4.5% 10 150K 160K 6.7%

20 175K 191K 9.1% 20 331K 350K 5.7%

Kho st tuyn tnh ca khung quay:

- Thang 5V

Gc lch (%) 10 20 30 40 50 60 70 80 90 100

Volt 1.11 1.55 1.93 2.35 2.75 3.16 3.53 3. 4.35 4.73

- Thang 10V

Gc lch (%) 10 20 30 40 50 60 70 80 90 100

Volt 1.66 2.48 3.5 4.13 5.1 5.85 6.62 7.56 8.42 9.45

- Thang 20V

Gc lch (%) 10 20 30 40 50 60 70 80 90 100

Volt 3 4.8 6.5 8.3 10.1 12 13.6 15.5 17.5 19.5

V th.

th hin s p ng tuyn tnh ca khung quay.

BO CO TH NGHIM

O IN T

Sinh vin : Hu Lim - 40801077

BI 2: KHO ST P NG TN S CA 1 VOLT K XOAY

CHIU

I.Trnh t th nghim:

1. Kho st p ng tn s ca cc loi vole k :

a.S mch th nghim .

b.Thc hnh th nghim.

-C 3 loi Volt k c s dng : Volt k kim Mrtrix , Volt k s

loi thng DT888 v Volt k s tr hiu dng thc SANWA.

-S dng my pht sng to sng sin bin 2V tn s trung tm

1KHz , ln lt dng cc volt k cho o Vac ,ghi nhn li gi

tr o c , thay i thnh cc dang tn hiu : sng vung lng

cc , vung n cc, tam gic . Ring loi True RMS th s c Vrms

v Vac , Vdc .

Ta c kt qu o bng sau :

Bng : p ng ca cc loi volt k khc nhau so vi cc dng in

p khc nhau.

Dng in p

Tr s Vm t OSC

Tr s o c t cc Volt k

Metrix

Vac

DT888

Vac

SANWA-True RMS

Vac Vdc Vrms

SINE 2V 1.4 1.37 1.27 73mV 1.34

Vung-2 cc 2V 2.15 2.23 1.782 8mV 1.79

Vung-1 cc 2V 2.45 2.23 0.7 2.05 2.75

Tam gic 2V 1.1 1.06 1.03 50.3mV 1.08

-i vi in p xoay chiu dng sin , tng dn tn s v gim dn

tn s tm khong p ng tn s cho tng loi volt k : khong

fl v fh . th in p o c khi tng dn tn s t fl n 2xfh :

A.Metrix :

Thang logarith

B.DT888:

C.Sanwa-True RMS:

H s dang K-f v h s nh K-p :

Sine: K-f =1.1 , K-p = 1.414

Vung: K-f = 1 , K-p = 1

Tam gic : K-f = 1.155 , K-p = 1.732

2.Kho st nh hng ca Volt k n in p ang o :

a.S mch th nghim :

b.Trnh t th nghim :

-S dng ln lt cc loi volt k o in p nh trn vi cc cp

in tr thay i .

-Ta c bng kt qu o vi tng loai volt k :

A.Metrix

Volt k Metrix nhy 2000 /V

Tm o Tr s in p

R1=R2=1K R3=R4=100K R5=R6=1M

10V 6.3 4.7 2

30V 5.8 5.5 0.5

100V 6 5.9 1

B.DT888

Volt k DT888

Tm o Tr s in p

R1=R2=1K R3=R4=100K R1=R2=1K

20V 5.85 6V 3.78

200V 5.6 6.3V 3.5

2000V 4 8V 1

C.SANWA-True RMS

Volt k DT888

Tm o Tr s in p

R1=R2=1K R3=R4=100K R1=R2=1K

Auto range 5.4 5.9 3.7

II.Bo co th nghim :

1. C cu chuyn i DC-AC bn trong cc loi Volt k . - i vi Volt k kim ( c cu in-t, t-in, in -ng ) : o DC

in p o c chuyn thnh dng in c ch th bi c cu ch

th ng.

o AC : in p AC qua mt mch nn dng sang DC a vo c

cu o DC :

-Chnh lu bng diode.

-B bin i nhit.

in tr phn tm o c mc ni tip vi in tr cung cp nhit

cho cp nhit in .

- i vi Volt k in t : o DC: dng mch cu o 2 transistor 2 mi ni , in p vo l n

cc B1 ca Q1, hoc B2 ca Q2 , cn lai ni mass . Hoc Vi sai

gia B1 v B2 .in p ly ra cc E hoc C ca transistors . Ngoi

ra cn dng FET . S dng thang chia p ng vo bng in tr

phn tm o.

hoc

o AC , s dng cc phng php sau chuyn AC thnh DC :

-Chnh lu dng diode

-PP tr hiu dung thc.

-PP tr chnh lu trung bnh .

Mch chuyn i AC-DC c khuch i v mch bin i p thnh

dng .

2.Cc loi Volt k c s dng trong th nghim :

Metrix MX 025C : loi t in k hiu

DT-888 : loi k thut s tr hiu dng trung bnh.

SANWA- true RMS CD721 : loi k thut s tr hiu dng thc .

p ng tn s i vi loi ch th kim l rt thp so vi loi k thut

s.

3.c gi tr trn Volt k nh chun theo tn hiu sine :

Sai s ca php o dng tn hiu c tnh theo h s dng :

Bo Co Th nghim

o in t

Bi 3 : o in Tr

Sinh vin : Hu Lim -40801077

A. o in tr:

I.Phng php Volt-ampe :

-o r ngn v r di .

-o :bng n , in tr s , in tr dy qun.

Ln Bng n in tr s in tr dy qun

o R ngn R di R ngn R di R ngn R di

U I R U I R U I R U I R U I R U I R

1 1.8 0.14 13 1.8 0.14 13 1.9 0.3m 6k3 1.8 0.4m 4k5 1.8 5m 360 1.8 7m 257

2 4.9 0.34 14 4.9 0.32 15 5 0.9m 5k5 4.9 1.4m 3k5 5 25m 200 5 27m 185

3 10 0.4 25 10 0.45 22 9.9 2.2m 4k5 10.5 2m 5k2 10 48m 208 10 54m 185

4 15 0.5 30 15 0.53 28 15 3.8m 4k 15 3.5m 4k3 15 78m 192 15 77m 195

5 20 0.58 34 20 0.58 34 20 4.8m 4k1 20 4.8m 4k2 20 90m 222 20 115m 174

II.Cu o chuyn dng ED :

1.o in tr ln

Loi in tr Ln o 1- G1 Ln o 2 - G2 Ln o 3 -G0

Tm o Gi tr Tm o Gi tr Tm o Gi tr

Al X1 1.9 X1 1.8 X1 2.2

Cu X0.1 4.4 X0.1 4.5 X0.1 4.3

Fe X0.1 3 X0.1 3 X0.1 2.5

2.o in tr nh

Loi in tr Ln o 1- G1 Ln o 2- G2 Ln o 3- G0

Tm o Gi tr Tm o Gi tr Tm o Gi tr

Fe X0.001 4 X0.001 7.5 X0.001 4.3

Al X0.001 2 X0.001 3 X0.001 2.2

Cu X0.001 3.5 X0.001 2.2 X0.001 3.3

B. o in tr tip t:

I.o bng Volt k v Ampe k :

a.o trc tip :

Gi

tr tnh

ton

Cc A (v B

Ln 1 Ln 2 Ln 3 Ln 4 Ln 5

U1 I1 U2 I2 U3 I3 U4 I4 U5 I5

30 0.15 24 0.14 17 0.1 12 0.07 6 0.03

R 20 171 170 171 200

a 182.4

Gi

tr tnh

ton

Cc C (v B)

Ln 1 Ln 2 Ln 3 Ln 4 Ln 5

U1 I1 U2 I2 U3 I3 U4 I4 U5 I5

3 0.07 11 0.21 17 0.31 25 0.47 34 0.64

R 43 52 55 53 53

51.225

b.o gin tip : R1=Ra+Rb , R2=Rb+Rc , R3=Rc+Ra .

A : , B:xanh ,C:trng .

Ln o 1

Cc A v B Cc B v C Cc C v A

U1 I1 R1 U2 I2 R2 U3 I3 R3

67 0.26 258 64 0.25 256 63 0.18 350

V tr th nht ca con tr bin tr

Ln o 2


U1 I1 R1 U2 I2 R2 U3 I3 R3

50 0.2 250 51 0.2 255 50 0.14 357

V tr th hai ca con tr bin tr

Ln o 3


U1 I1 R1 U2 I2 R2 U3 I3 R3

37 0.15 247 38 0.14 271 39 0.11 354

V tr th ba ca con tr bin tr

Ln o 4


U1 I1 R1 U2 I2 R2 U3 I3 R3

26 0.11 256 25 0.09 278 25 0.07 357

V tr th t ca con tr bin tr

Ln o 5


U1 I1 R1 U2 I2 R2 U3 I3 R3

11 0.057 193 12 0.04 300 12 0.03 433

V tr th nm ca con tr bin tr

Gi tr trung bnh ca :

- R1= 237 =Ra +Rb

- R2=272 = Rb+Rc

- R3=370 = Rc+Ra

Gi tr ca in tr cc cc :

- Ra=185

- Rb=90

- Rc=180

II.o bng my o chuyn dng :

Kt qu t my o chuyn dng :

- Ra=185

- Rb=87

- Rc=185

Bo Co Th Nghim

o in T

Bi 4 : o in dung v in cm


A.o in dung-in cm bng cu n gin :

1. o in dung bng cu

S mch th nghim :

Ln o T in 1 T in 2

P Q Cmu CX(uF) P Q Cmu CX(uF)

1 1k 1k 1.08u 1.08u 1k 1k 4.26u 4.26u

2 2k 1k 0.56u 1.12u 2k 1k 2.1u 4.2u

3 3k 2k 0.72u 1.1u 3k 2k 3.02u 4.53u

Gi s cc gi tr trn l kq ca php o m hnh ni tip.

Khi cu cn bng :

Cn bng phn thc :

Cn bng phn o : trng hp R3=R4 nn Cmu =Cx. , Rx=R1

2. o in cm bng cu :

Ln o Cun dy 1 Cun dy 2

P Q R Lmu LX(mH) P Q R Lmu LX(mH)

1 3k 2k 20 6.3m 9.45m 3k 2k 10 1.5m 2.25m

2 2k 1k 30 4.06m 8.1m 2k 1k 10 1.3m 2.6m

3 1k 1k 20 8m 8m 1k 1k 10 2.1m 2.1m

Cu khng thc s cn bng do ta dng in tr nh hn dng trong mch . Gi tr tnh gn

ng.

Ngoi loi cu o n gin , ngi ta cn dng cu ph qut o in dung :

a/ Cu Sauty b/ Cu Nernst

o in cm bng cu Maxwell :

a/ Cu Maxwell-Wien b/ Cu Hay

Cu Owen o cun dy dng in dung mu , cu Schering o in dung

a/ Cu Owen b/ Cu Schering

B. S dng cu o chuyn dng:

Bng gi tr cc t: o vi 2 tm o gn nht , do ti a ca my ch c tm 10uF nn khng th dng o 2 ln i

vi t 1 v gi tr o ln 1 tm 10uF l ~4uF .

Ln o Tm o T 1 Tm o T 2

1 10uF 4.1uF 1uF 1uF

2 - - 10uF 1.1uF

Cu o loi n gin ch xc nh c thun ty gi tr Cx v Lx cn o , khng xc nh c

s hao mt trn in dung v in cm cn do . Trn thc t s hao mt ca in dung v in

cm c quy i v 2 m hnh ni tip v song song ty theo s hao mt in dung , cht lng

in dung c nh gi qua h s D ca in dung , in cm c h s Q:

CC M HNH QUY I DO HAO MT IN DUNG V IN CM

Hao mt nh th in dung D c h s D nh : D,0.1 gi l nh . Cun dy c h s phm

cht cao tc l hao mt nh , Q>10

Bo Co Th Nghim

o in T

Bi 5 : o Tn S V Pha


I. Quan st dng :

Ngun pht sng Tr nh Chu k Vmax Vmin

My pht m tn Tr nh Chu k Vmax Vmin

p li cch ly Tr nh Chu k Vmax Vmin

II. o tn s : S mch:

Hnh dng s b :

III. o lch pha:

1. Phng php lissajous : S mch th nghim :

Khng c bin p: C bin p cch ly

Hnh dng s b:

2. So snh pha trc tip :

S mch th nghim:

Khng c bin p C bin p cch ly

Hnh dng s b :

3. So snh pha gin tip :

S mch th nghim :

Khng c bin p C bin p cch ly

Hnh dng s b :

gi l cao.

76216663 Bach Khoa Tp Hcm

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Transcript of 76216663 Bach Khoa Tp Hcm