Measurement of temperature and detection of radiation are the two important applications of Seebeck effect.
Thermoelectric Thermometer
To measure temperature , we use thermocouple consisting of copper and constantan with one junction in contact with the region whose temperature is to be measured and the other junction in a constant temperature bath.
One end of the thermocouple is kept at a standard temperature , say ice at triple point and the other end of the couple kept at the region of known temperature . An electronic Voltmeter is connected in series with the arrangement to measure thermo emf. The thermocouple is the preferred way of measuring temperature , because of its accuracy , and convenience . Since the junction is small it absorbs very little heat, and quickly attain the temperature being measured. Copper-gold iron alloy thermocouple is used to measure 1K to 50K.
Copper-constantan thermocouple is used to measure 50K to 400K. Platinum-Rhodium Platinum alloy thermocouple is used to measure 1500K to 2000K.
Thermopile
Thermopile consists of large no of antimony bismuth thermo couples connected in series. One set of the junctions are kept at constant temperature. A galvanometer included in series is used to measure the thermoelectric voltage. When thermal radiation falls on balckened junction its temperature rrises and thermo-emf proportional to the intensity of radiation is developed. Thus by noting the amount of deflection or from the thermo-emf developed the intensity of radiation can be obtained.
Thermoelectric Thermometer
To measure temperature , we use thermocouple consisting of copper and constantan with one junction in contact with the region whose temperature is to be measured and the other junction in a constant temperature bath.
One end of the thermocouple is kept at a standard temperature , say ice at triple point and the other end of the couple kept at the region of known temperature . An electronic Voltmeter is connected in series with the arrangement to measure thermo emf. The thermocouple is the preferred way of measuring temperature , because of its accuracy , and convenience . Since the junction is small it absorbs very little heat, and quickly attain the temperature being measured. Copper-gold iron alloy thermocouple is used to measure 1K to 50K.
Copper-constantan thermocouple is used to measure 50K to 400K. Platinum-Rhodium Platinum alloy thermocouple is used to measure 1500K to 2000K.
Thermopile
Thermopile consists of large no of antimony bismuth thermo couples connected in series. One set of the junctions are kept at constant temperature. A galvanometer included in series is used to measure the thermoelectric voltage. When thermal radiation falls on balckened junction its temperature rrises and thermo-emf proportional to the intensity of radiation is developed. Thus by noting the amount of deflection or from the thermo-emf developed the intensity of radiation can be obtained.
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