Comparative Point |
Thermistor |
Thermocouple |
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Material used |
Metallic oxides of Cu, Ni, Fe. |
Metals like copper, iron, platinum, rhodium or alloys like constantan. |
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Output reading |
Actual temperature of object. |
Temperature difference between temperature of cold junction and hot junction. |
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Operating or Temperature range |
Narrow operating range from – 150°C to 300°C. |
Wide operating range from -200° to 1600°C. |
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Construction |
Complex. |
Simple, but rigid. |
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Size |
Very small. |
Comparatively much larger. |
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Cost |
Expensive. |
Cheaper. |
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Effect of environmental conditions |
No effect on accuracy. |
Accuracy gets affected. |
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Sensitivity |
Extremely sensitive. It rapidly measures temperature of object, because temperature change is directly proportional to change in resistance of sensing element. |
Considered to be less sensitive, because of very small emf output. |
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Response |
Better response. |
Comparatively slow response. |
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Need of insulation |
No as insulation covering is not required, during temperature measurement of any conducting fluid. |
Yes as insulation covering is required, during temperature measurement of any conducting fluid. |
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Applications |
(a) Used for temperature measurement with control. (b) Used for controlling liquid level. |
Used for temperature measurement only. |