LM185-2.5/LM285-2.5/LM385-2.5
LM385-2.5 Applications
(Continued)
Micropower Thermocouple Cold Junction
Compensator
DS005519-6
Adjustment Procedure
1.
Adjust TC ADJ pot until voltage across R1 equals Kelvin
temperature multiplied by the thermocouple Seebeck
coefficient.
Adjust zero ADJ pot until voltage across R2 equals the
thermocouple Seebeck coefficient multiplied by 273.2.
Seebeck
Thermocouple
Type
J
T
K
S
Co-
efficient
(
µ
V/˚C)
52.3
42.8
40.8
6.4
523 1.24k
432
1k
412 953Ω
63.4 150Ω
R1
(Ω)
R2
(Ω)
Voltage
Across R1
@
25˚C
2.
Voltage
Across R2
(mV)
14.32
11.78
11.17
1.766
(mV)
15.60
12.77
12.17
1.908
Typical supply current 50 µA
Improving Regulation of Adjstable Regulators
DS005519-7
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