“thermocouple”的概念、定义、翻译、参考文献-科学参考

thermocouple

Physics

A device consisting of two dissimilar metal wires or semiconducting rods welded together at their ends. A thermoelectric e.m.f. is generated in the device when the ends are maintained at different temperatures, the magnitude of the e.m.f. being related to the temperature difference. This enables a thermocouple to be used as a thermometer over a limited temperature range. One of the two junctions, called the hot or measuring junction, is exposed to the temperature to be measured. The other, the cold or reference junction, is maintained at a known reference temperature. The e.m.f. generated is measured by a suitable millivoltmeter or potentiometer incorporated into the circuit. See Seebeck effect; thermopile.

Astronomy

An instrument that turns heat into an electric current. It consists of two wires of different metals joined together at their ends. When heat falls on one of the junctions while the other junction is kept cold, an electric current is produced. A thermocouple thus acts as a thermometer for radiant heat. Thermocouples are of low sensitivity but can be used from the microwave region to the ultraviolet. They are used in astronomy mainly to calibrate more sensitive detectors operating in different parts of the spectrum.

Chemical Engineering

A temperature-sensing instrument that consists of a pair of dissimilar metal wires joined together. One pair of wires operates as a reference junction and the other as the sensing junction. Where a temperature difference exists, an e.m.f. difference is measured and a current flows from which the temperature is determined.

Electronics and Electrical Engineering

Two dissimilar metals joined at each end to form an electrical circuit. If the two junctions are maintained at different temperatures an electromotive force (e.m.f.) is developed between them as a result of the Seebeck effect (see thermoelectric effects). The e.m.f. is not affected by the presence of other metal junctions provided that they are all maintained at the same temperature. The thermocouple may therefore be connected to a suitable measuring instrument and used as a thermometer. It is convenient in use since it functions over a wide temperature range, it can be used to measure temperature at a very small area, and may be used remotely from the indicating instrument. The range of temperatures measured depends on the materials used.
In practice one junction is held at 0 °C and then the e.m.f. E is given by
$E = α T^{2} + β T$
where T is the temperature of the other junction – the ‘hot’ junction–and α and β are constants dependent on the metals used. At a temperature T_N where
$T_{N} = - \frac{β}{2 α}$
E is a maximum. T_N is termed the neutral temperature and the use of the thermocouple is normally restricted to temperatures in the range 0 – T_N °C. Copper/constantan or iron/constantan thermocouples can be used up to 500 °C. Temperatures up to about 1500 °C may be measured using a platinum/platinum-rodium alloy thermocouple and even higher temperatures may be measured by means of an iridium/iridium-rhodium alloy thermocouple.
Thermocouple instruments are measuring instruments that use a thermocouple to measure electric current, voltage, or power by means of the heating effect produced by the current in a metallic strip or wire. The current-carrying strip or wire plus thermocouple are sealed into an evacuated container in order to minimize errors in the measurement due to conduction of heat by the air surrounding the conductor.
The sensitivity of a thermocouple instrument is increased by connecting several couples together in series to form a thermopile. An easily detectable output is produced by heat radiation impinging on the hot junctions. The thermal battery is a thermopile that is used to generate an e.m.f. when heat is supplied to the hot junctions.

单词	thermocouple
释义	thermocouple Physics A device consisting of two dissimilar metal wires or semiconducting rods welded together at their ends. A thermoelectric e.m.f. is generated in the device when the ends are maintained at different temperatures, the magnitude of the e.m.f. being related to the temperature difference. This enables a thermocouple to be used as a thermometer over a limited temperature range. One of the two junctions, called the hot or measuring junction, is exposed to the temperature to be measured. The other, the cold or reference junction, is maintained at a known reference temperature. The e.m.f. generated is measured by a suitable millivoltmeter or potentiometer incorporated into the circuit. See Seebeck effect; thermopile. Astronomy An instrument that turns heat into an electric current. It consists of two wires of different metals joined together at their ends. When heat falls on one of the junctions while the other junction is kept cold, an electric current is produced. A thermocouple thus acts as a thermometer for radiant heat. Thermocouples are of low sensitivity but can be used from the microwave region to the ultraviolet. They are used in astronomy mainly to calibrate more sensitive detectors operating in different parts of the spectrum. Chemical Engineering A temperature-sensing instrument that consists of a pair of dissimilar metal wires joined together. One pair of wires operates as a reference junction and the other as the sensing junction. Where a temperature difference exists, an e.m.f. difference is measured and a current flows from which the temperature is determined. Electronics and Electrical Engineering Two dissimilar metals joined at each end to form an electrical circuit. If the two junctions are maintained at different temperatures an electromotive force (e.m.f.) is developed between them as a result of the Seebeck effect (see thermoelectric effects). The e.m.f. is not affected by the presence of other metal junctions provided that they are all maintained at the same temperature. The thermocouple may therefore be connected to a suitable measuring instrument and used as a thermometer. It is convenient in use since it functions over a wide temperature range, it can be used to measure temperature at a very small area, and may be used remotely from the indicating instrument. The range of temperatures measured depends on the materials used. In practice one junction is held at 0 °C and then the e.m.f. E is given by $E = α T^{2} + β T$ where T is the temperature of the other junction – the ‘hot’ junction–and α and β are constants dependent on the metals used. At a temperature T_N where $T_{N} = - \frac{β}{2 α}$ E is a maximum. T_N is termed the neutral temperature and the use of the thermocouple is normally restricted to temperatures in the range 0 – T_N °C. Copper/constantan or iron/constantan thermocouples can be used up to 500 °C. Temperatures up to about 1500 °C may be measured using a platinum/platinum-rodium alloy thermocouple and even higher temperatures may be measured by means of an iridium/iridium-rhodium alloy thermocouple. Thermocouple instruments are measuring instruments that use a thermocouple to measure electric current, voltage, or power by means of the heating effect produced by the current in a metallic strip or wire. The current-carrying strip or wire plus thermocouple are sealed into an evacuated container in order to minimize errors in the measurement due to conduction of heat by the air surrounding the conductor. The sensitivity of a thermocouple instrument is increased by connecting several couples together in series to form a thermopile. An easily detectable output is produced by heat radiation impinging on the hot junctions. The thermal battery is a thermopile that is used to generate an e.m.f. when heat is supplied to the hot junctions.
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