毕业设计文献翻译热电偶温度传感器(6)

毕业设计文献翻译热电偶温度传感器Thermocouple Temperatur sensor

vaporization.

Measuring temperature differences

Thermocouples are excellent for measuring temperatures differences, such as the wet bulb depression in measuring humidity. Sensitivity can be enhanced by constructing a thermopile - a number of thermocouple circuits in series.

In the above example, the thermopile output is proportional to the temperature difference T1 - T2, with a sensitivity three times that of a single junction pair. In practice, thermopiles with two to hundreds of junctions are used in radiometers, heat flux sensors, flow sensors and humidity sensors. The thermocouple materials can be in wire form, but also printed or etched as foils and even electroplated.

An excellent example of the thermopile is in the heat flux sensors manufactured by Hukseflux Thermal Sensors. Also see RdF Corp. and Exergen Corp.

The thermocouple is unique in its ability to directly measure a temperature difference. Other sensor types require a pair of closely matched sensors to ensure tracking over the entire operational temperature range.

The thermoelectric generator

While the Seebeck voltage is very small (in the order of 10-70μV/°C), if the circuit's electrical resistance is low (thick, short wires), then large currents are possible (e.g. many amperes). An efficiency trade-off of electrical resistance (as small as possible) and thermal resistance (as large as possible) between the junctions is the major issue. Generally, electrical and thermal resistances trend together with different materials. The output voltage can be increased by wiring as a thermopile.

The thermoelectric generator has found its best-known application as the power source in some spacecraft. A radioactive material, such as plutonium, generates heat and cooling is provided by heat radiation into space. Such an atomic power source can reliably provide many tens of watts of power for years. The fact that atomic generators are highly radioactive prevents their wider application. 热电偶温度传感器

介绍了热电偶

热电偶是一种最简单的传感器。它由两线异种金属的加入测量点附近。输出是一个很小的电压测量两线之间。

虽然在概念上吸引人的简单，在热电偶理论是微妙的，其中的基本知识需要了解传感器的最有效使用。