RESISTANCE - TEMPERATURE TABLES

NTC (Negative Temperature Coefficient) is the negative percent resistance change per degree C. To determine the resistance tolerance of a precision thermistor at any temperature point, multiply the temperature tolerance time the NTC.

As an example, a Curve A thermistor with a temperature tolerance of  +1 over the temperature range 0 to 70 would have the following resistance tolerance:    0=+5.1%; 25=+4.4%; 70=+3.4%

RT/R25 Ratio is the resistance at temperature divided

 

by the resistance at 25. To determine the resistance at other temperature points, multiply the coefficient by the R25 value.

Ratio TOL(Tolerance) is the resistance tolerance at a temperature point due to slope variance from the nominal R-T Curve. This tolerance applies to thermistors point-matched to a single temperature point. The ratio tolerance is added to the percent resistance tolerance at the point-matched temperature.

 

 

CURVE  A

CURVE  B

CURVE  C

CURVE  D

B 25/85

3975K

3942K

3695K

4262K

Temp

Typical R25=1K to 100K

RT/R25 RATIO

 

RATIO    TOL    NTC

Typical R25=10K to 100K

RT/R25 RATIO

 

RATIO    TOL    NTC

Typical R25=5K to 20K

RT/R25 RATIO

 

RATIO    TOL    NTC

Typical R25=25K to 100K

RT/R25 RATIO

 

RATIO    TOL    NTC

-50

67.13

3.5

7.1

56.39

3.5

6.7

44.13

3.5

6.3

82.36

3.5

7.4

-45

47.26

 

6.9

40.56

 

6.5

32.36

 

6.1

57.30

 

7.1

-40

33.69

3.0

6.7

29.48

3.0

6.3

23.97

3.0

5.9

40.34

3.0

6.9

-35

24.29

 

6.4

21.64

 

6.1

17.92

 

5.3

28.72

 

6.7

-30

17.71

2.4

6.2

16.03

2.4

5.9

13.52

2.4

5.6

20.67

2.4

6.5

-25

13.05

 

6.0

11.99

 

5.7

10.29

 

5.4

15.02

 

6.3

-20

9.711

1.9

5.8

9.040

1.9

5.6

7.891

1.9

5.2

11.03

1.9

6.1

-15

7.297

 

5.6

6.875

 

5.4

6.102

 

5.1

8.174

 

5.9

-10

5.534

1.4

5.4

5.270

1.4

5.2

4.754

1.4

4.9

6.113

1.4

5.7

-5

4.234

 

5.3

4.071

 

5.1

3.731

 

4.8

4.611

 

5.6

0

3.266

1.0

5.1

3.168

1.0

4.9

2.949

1.0

4.6

3.507

1.0

5.4

5

2.540

 

5.0

2.483

 

4.8

2.346

 

4.5

2.689

 

5.2

10

1.991

0.5

4.8

1.959

0.5

4.7

1.879

0.5

4.4

2.077

0.5

5.1

15

1.572

 

4.7

1.556

 

4.5

1.514

 

4.3

1.617

 

4.9

20

1.249

0.1

4.5

1.244

0.1

4.4

1.227

0.1

4.1

1.267

0.1

4.8

25

1.000

0.0

4.4

1.000

0.0

4.3

1.000