PhysicalLabReport:TemperatureSensors

Writer:No:

Thistimeinthelab,Icometodosomethingabouttemperaturesensors.Beforetheexperiment,Iknowthattemperaturesensorsareverywidelyusedlabequipment.Fromtheguide,Icanfindtheiroutputschangesasafunctionoftemperature.ThemostcommonlyusedonesinthelabarePlatinumresistorsandsemiconductorthermocouples.

Inthisexperiment,IwilldescribetheworkingprincipleofPlatinumthermo-resistors,Semi-conductorthermo-resistor,andPNdiodetemperaturesensor,andmakemeasurementswiththeminthelab.

Atthebeginning,Iusetheicewatertogetthereferencepointtozerodegreeis2degree.So,whenIdealwiththedata,Ihavechangedthetemperatureintocorrectonesalready.

1.Semi-conductorthermo-resistor

Withinrange,theresistanc-temperaturerelationis

IfwecalibratetheresistanceatatemperatureT0tobeR0,wecanrewritethisrelationinto

T/C

45

48

50

53

55

58

61

64

70

73

78

80

82

84

86

88

90

93

96

99

102

105

108

111

113

115

118

R/

4000

3702

3473

3106

2868

2544

2303

2101

1744

1569

1343

1282

1212

1146

1089

1018

967

896

838

773

724

668

624

586

561

538

505

AfterIchangetheunitoftemperatureintoK,Iusecomputertomakealinearfitandgetagraphasfollows:

Theslopeofthelineisequalto1555.6,itmeansB=1555.6K.whichisalittlebitsmallerthanthereference.

Platinumthermo-resistors

Aplatinumresistorhasatemperature-resistancerelationof

T/C

27

30

33

36

39

42

45

48

51

54

57

60

63

66

69

72

75

78

83

88

93

98

U/V

0.115

0.1183

0.1212

0.1235

0.126

0.1283

0.1303

0.1321

0.1341

0.1362

0.138

0.1397

0.1413

0.143

0.1446

0.1465

0.1479

0.1494

0.1516

0.1541

0.1562

0.1583

T/C

14

11

8

5

2

0

-2

-4

-6

-7

-8

U/V

0.1064

0.1057

0.1049

0.1044

0.1036

0.103

0.1024

0.1018

0.1012

0.1008

0.1003

Fromthegraph,Igetthecoefficientofx2isB=2.8*10-7oC-２,thecoefficientofxisA=6*10-4C－１

PNdiodetemperaturesensor

T/C

35

38

42

45

47

51

53

55

57

59

61

64

66

98

99

101

103

U/V

0.47

0.462

0.45

0.4414

0.4366

0.4246

0.4201

0.4138

0.4075

0.4017

0.3958

0.3884

0.3835

0.2961

0.2929

0.2884

0.283

T/C

69

72

74

76

78

80

83

85

87

88

90

92

94

96

105

106

110

U/V

0.3752

0.3665

0.3606

0.3553

0.3501

0.3449

0.3386

0.3318

0.3264

0.3228

0.3172

0.3123

0.3063

0.3019

0.2771

0.2746

0.2634

T/C

14

12

9

7

5

3

2

0

-1

-2

-3

-4

-5

U/V

0.5122

0.5164

0.5221

0.5265

0.53

0.5334

0.5351

0.5387

0.5408

0.5425

0.5445

0.546

0.5468

Semiconductordiodesbeginconductingelectricityonlyifacertainthresholdvoltageorcut-involtageispresentintheforwarddirection.Thevoltagedropacrossaforward-biaseddiodevariesonlyalittlewiththecurrent,andisafunctionoftemperature;thiseffectcanbeusedasa

temperaturesensor.Withinagivenrangeoftemperature,theresistancevarieslinearlywithtemperature.

U=-0.0025T+0.5425，astheI=100μA,so,R=-25T+5424,thetemperatureis25

Erroranalysis:

Thetemperatureistestedindirectly,sothemeasuredtemperatureisalittleslowerorhigherthanthecorrectone,Ifnotprecise,thenourresultoft