选择一个热敏电阻或RTD
传感器用于测量温度可以包括热电偶,电阻温度装置(RTDs和热敏电阻),红外辐射器,金属设备,液体膨胀设备,及其他。在过去的几年里,在精确度、互换性和稳定性方面,令人印象深刻和广泛的改进促使许多应用程序增加热敏电阻的使用,这将是本文的重点。
这些热敏电阻(因此,它们的名称,“热”和“电阻”的收缩)在温度变化时具有电阻大且可预测的变化。热敏电阻越大,电阻值越高,其耗散功率越大。热敏电阻是高度敏感的,重复性很好的电阻-温度特性。
而这些设备都是廉价收购,真正的储蓄是因为它们不需要安装传感器的寿命期间校准或校准。相反,他们是年龄离开制造商使漂移最小化之前,而这些传感器一般轻微的温度变化反应迅速,探头类型的热敏电阻的反应时间是物质依赖。
Types of resistive temperature sensors
Two types of resistive temperature sensing devices are based on changes in the electrical resistance of material relative to temperature changes: negative temperature coefficient (NTC) thermistors and resistive temperature detectors (RTDs)。 We will look at both, starting with NTCs.
While the NTC variety is manufactured from the oxide of manganese, cobalt, copper, and nickel, it operates over a range of –200°C to 1,000°C. Thermistors can be bought in glass bead, disc, chips, and probe options. Used extensively in such applications as temperature measurement and control, temperature compensation, surge suppression, and fluid flow measurement, they should be selected when a continuous change of resistance is necessary spanning a wide temperature range. They offer high stability and a high degree of sensitivity.
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