AMS3100-1 Datasheet, PDF (4/6 Pages) –

TYPICAL APPLICATIONS (Continued)
AMS3100-1.2
Micropower Thermocouple Cold Junction Compensator
V⁺
LM334
5.1k
1M
1%
V^-
MERCURY
CELL
+
1.345V
ZERO
ADJ 100k
AMS3100-1.2
2k
R ^1%
TC ADJ
500
R2
R1
+
THERMOCOUPLE
-
COLD JUNCTION
ISO THERMAL
WITH LM334
+
METER
-
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.
Thermocouple
Type
Seebeck
Coefficient
(mV/ °C)
R1 R2 Voltage
Voltage
(Ω) (Ω) Across R1 Across R2
@ 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
408 953Ω 12.17
11.17
S
6.4
63.4 150Ω 1.908
1.766
Typical supply current 50µA
Precision 1µA to 1mA Current Sources
AMS3100-1.2
AMS3100-1.2
30V
C1
150pF
R1
100k
I_OUT*
-1.5V TO -27V
2-
7
LM312
6
3+
4
R2
-30V
*IOUT =1.23V/R2
1.5V TO 27V
R1
100k
I_OUT*
2-
7
LM312
3+
4
C1
150pF
6
R2
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