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Thermocouple Types & Characteristics |
|
Type |
Temp.
Range °C
(8 AWG Wire) |
Temp.
Range °C
(24 AWG Wire) |
Materials |
Output |
Properties & Use |
|
K |
-270 to +1300 |
-270 to +820 |
chromel-alumel |
41 µV/°C |
General purpose, low
cost, is magnetic, low oxidation. Used extensively
at temperatures up to 1300° C. Use of metal or
ceramic protective tube is recommended, especially
in reducing atmospheres. In oxidizing atmospheres
protective tubing not essential, but desirable for
longer service. |
|
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J |
-210 to +760 |
-210 to +370 |
iron-constantan |
50 µV/°C |
Limited range, high
output, is magnetic, subject to oxidation. Used with
or without protective tubing where deficiency of
free oxygen exists. Protective tube recommended but
not essential, desirable for cleanliness and longer
service. Since JP wire oxidizes rapidly above 530°
C, compensate by using larger gauge wires. Maximum
recommended operating temperature: 760° C. |
|
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N |
0 to +1300 |
0 to +820 |
nicrosil-nisil |
39 µV/°C |
High
temperature, high stability, is non-magnetic. Used
extensively at temperatures up to 1300° C. Use of
metal or ceramic protective tube is recommended,
especially in reducing atmospheres. In oxidizing
atmospheres protective tubing not essential, but
desirable for longer service. |
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R |
-50 to +1768 |
-50 to +1768 |
platinum–rhodium
|
10 µV/°C |
Very stable, high
temperature, easily contaminated, high cost, low output.
For high temperature applications in oxidizing
atmospheres. Use a ceramic protection tube to obtain
maximum reliability above 985° C in a neutral
atmosphere, or air above 1100° C. |
|
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S |
-50 to +1768 |
-50 to +1768 |
platinum–rhodium
|
10 µV/°C |
Very stable, high
temperature, easily contaminated, high cost, low output.
For high temperature applications in oxidizing
atmospheres. Use a ceramic protection tube to obtain
maximum reliability above 985° C in a neutral
atmosphere, or air above 1100° C. |
|
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B |
0 to +1820 |
0 to +1820 |
platinum–rhodium
|
10 µV/°C |
Very stable, high
temperature, easily contaminated, high cost, low output.
For high temperature applications in oxidizing
atmospheres, Type B reduces effects of chemical
contamination and rhodium migration. It has greater
mechanical strength than types S and R. Use a
ceramic protection tube to obtain maximum
reliability above 985° C in a neutral atmosphere, or
air above 1100° C. |
|
|
T |
-270 to +400 |
-270 to +200 |
copper-constantan |
43 µV/°C |
Low temperature,
is non-magnetic, very low oxidation. Use in either
oxidizing or reducing atmospheres. Protection tube
not essential but recommended for cleanliness and
longer service. Stable at lower temperatures.
Superior for a wide variety of use in low cryogenic
temperatures. Operating range: - 185° C to 400° C,
but can be used to
- 218° C (boiling helium). |
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E |
-270 to +1000 |
-270 to +430 |
chromel-constantan |
68 µV/°C |
High output,
is non-magnetic, no corrosion. Suitable for use at
temperatures up to 870° C in vacuum, inert, mildly
oxidizing or reducing atmospheres. Not subject to
corrosion at cryogenic temperatures. Has highest EMF
output per degree of all commonly used
thermocouples. |
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