Fahrenheit Thermometer

DS005698-24

*To calibrate adjust R2 for 2.554V across LM336.

Adjust R1 for correct output.

THERMOCOUPLE COLD JUNCTION COMPENSATION

Compensation for Grounded Thermocouple

DS005698-6

*Select R3 for proper thermocouple type

THERMO-

R3

SEEBECK

COUPLE

COEFFICIENT

J

377

Ω

52.3 µV/˚C

T

308

Ω

42.8 µV/˚C

K

293

Ω

40.8 µV/˚C

S

45.8

Ω

6.4 µV/˚C

Adjustments: Compensates for both sensor and resistor tolerances

1. Short LM329B

2. Adjust R1 for Seebeck Coefficient times ambient temperature (in degrees K) across R3.

3. Short LM335 and adjust R2 for voltage across R3 corresponding to thermocouple type

J

14.32 mV

K

11.17 mV

T

11.79 mV

S

1.768 mV

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