76216663 Bach Khoa Tp Hcm
description
Transcript of 76216663 Bach Khoa Tp Hcm
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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
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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
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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
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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
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- 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.
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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.
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-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
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-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
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B.DT888:
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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
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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
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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
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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.
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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 :
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-Chnh lu dng diode
-PP tr hiu dung thc.
-PP tr chnh lu trung bnh .
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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
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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 :
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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
Cc A v B Cc B v C Cc C v A
U1 I1 R1 U2 I2 R2 U3 I3 R3
50 0.2 250 51 0.2 255 50 0.14 357
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V tr th hai ca con tr bin tr
Ln o 3
Cc A v B Cc B v C Cc C v A
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
Cc A v B Cc B v C Cc C v A
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
Cc A v B Cc B v C Cc C v A
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
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- Rc=185
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Bo Co Th Nghim
o in T
Bi 4 : o in dung v in cm
Sinh vin : Hu Lim -40801077
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 :
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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
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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:
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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
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Bo Co Th Nghim
o in T
Bi 5 : o Tn S V Pha
Sinh vin : Hu Lim -40801077
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 :
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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:
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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.