LM185-1.2QML

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SNVS384B – OCTOBER 2005 – REVISED JANUARY 2014

Calibration

1. Adjust R1 so that V1 = temp at 1mV/°K

2. Adjust V2 to 273.2mV

age = 50

μA to 150μA

Typical supply current 50

μA

Figure 24. Centigrade Thermometer

Adjustment Procedure

1. Adjust TC ADJ pot until voltage across R1 equals Kelvin temperature multiplied by the thermocouple Seebeck

coefficient.

2. Adjust zero ADJ pot until voltage across R2 equals the thermocouple Seebeck coefficient multiplied by 273.2.

Figure 25. Micropower Thermocouple Cold Junction Compensator

Seebeck

Voltage

Voltage

Thermocouple

R1

R2

Coefficient

Across R1

Across R2

Type

(

Ω)

(

Ω)

(

μV/°C)

@ 25°C (mV)

(mV)

J

52.3

523

1.24k

15.60

14.32

T

42.8

432

1k

12.77

11.78

K

40.8

412

953

12.17

11.17

S

6.4

63.4

150

1.908

1.766

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