尽管它们都是测量物体的温度,作用虽相同，但是原理和特点却不同。 The contact type temperature measurement in temperature measurement includes thermocouple and thermal resistance . Although they both measure the temperature of the object , although the function is the same, the principle and characteristics are different.
它的测温范围宽,性能比较稳定,同时结构也比较简单,动态响应好,甚至能够远传4-20mA电信号,有利于自动控制和集中控制。 The most widely used temperature device in temperature measurement is a thermocouple.It has a wide temperature measurement range and stable performance.At the same time, the structure is relatively simple , and the dynamic response is good.It can even transmit 4-20mA electrical signals remotely , which is conducive to automatic control and Centralized control. 如果当两个接点处的温度不一样时，在回路中将会产生热电势, ,热电效应又可以称之为塞贝克效应。 The thermocouple temperature measurement principle is based on the thermoelectric effect. The thermoelectric effect is to connect two different conductors or semiconductors into a closed loop . If the temperature at the two contacts is different, a thermoelectric potential will be generated in the loop. The effect can also be called the Seebeck effect. There are generally two types of thermoelectric potentials generated in closed loops: temperature difference potentials and contact potentials. 不同的导体具有不同的电子密度这样就形成了温差电势；而接触电势是指两种不同的导体相接触时,他们的电子密度不同，因此产生一定的电子扩散,当达到一定的平衡后所形成的电势。 The potential at two ends of the same conductor due to different temperatures , different conductors have different electron densities, which forms a temperature difference potential; contact potential refers to the fact that when two different conductors are in contact , their electron densities are different, which results in The potential that a certain electron diffuses when it reaches a certain equilibrium.
Thermocouples have two structures: ordinary thermocouples and armored thermocouples . 绝缘管,保护套管和接线盒等部分组成,而铠装型热电偶则是将热电偶丝,绝缘材料和金属保护套管三者组合后,经过拉伸加工而成的一种坚实的组合体。 The ordinary thermocouple is generally composed of a thermal electrode , an insulating tube , a protective sleeve, and a junction box.The armored thermocouple is a combination of a thermocouple wire , an insulating material and a metal protective sleeve . It is a solid combination made by drawing. 而这种特殊的导线我们称为补偿导线。 However, a special kind of wire is needed to transmit the electrical signal of the thermocouple , and this special kind of wire is called a compensation wire. 使热电偶的参比端远离电源,从而使参比端温度稳定。 Since the thermocouples are different, different compensation wires need to be connected to keep the reference end of the thermocouple away from the power supply , so that the temperature of the reference end is stable. ）补偿型，（ 2 ）延长型。 The compensation leads are divided into: ( 1 ) compensation type, ( 2 ) extension type.
由于他的测温范围使他受到了一定的限制,基于导体或者半导体的电阻值随着温度的变化而变化的特性是热电阻的测温原理。 Although the thermal resistance is widely used in industry, it is limited by his temperature measurement range. The principle of thermal resistance measurement is based on the characteristic of the resistance value of the conductor or semiconductor changing with temperature. 远传电信号,灵敏度高,稳定性强,互换性以及准确性都比较好,缺点是：需要电源激励,不能够瞬时测量温度的变化。 Its advantages are also : long- distance transmission of electrical signals , high sensitivity , strong stability , interchangeability and accuracy are relatively good , the disadvantages are: the need for power excitation , can not measure temperature changes instantly. 铂热电阻的测温的范围一般为零下200-800 ℃ ,铜热电阻为零下40到140 ℃。 In industry, Pt100, Pt10, Cu50, Cu100 and Pt100, Pt100, Pt100, Pt100, Pt100 and Pt100 are used.