LM135, LM135A, LM235, LM235A, LM335, LM335A

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SNIS160D – MAY 1999 – REVISED MARCH 2013

Figure 26. Fahrenheit Thermometer

*To calibrate adjust R2 for 2.554V across LM336.

Adjust R1 for correct output.

Figure 27. THERMOCOUPLE COLD JUNCTION COMPENSATION

Compensation for Grounded Thermocouple

*Select R3 for proper thermocouple type

THERMO-COUPLE

R3 (±1%)

SEEBECK 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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