Daily Question on Automation Theory Knowledge (9.4)

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This post was last edited by 18663069001 on 2017-9-6 at 17:08. Process and instrumentation are inseparable; to help everyone gain a better understanding of the basic concepts related to instrumentation, we have launched the \"One Question per Day\" initiative – just reply to get the answer. To encourage ongoing participation from everyone! Get a wealth reward just for participating! Higher rewards for correct answers! I hope everyone will participate actively, learn together, and make progress together! ! ! Multiple-choice question: 50. Compared with platinum thermoresistors, what is the temperature measurement range of copper thermoresistors? ( ) (A) Wide (B) Narrow (C) The same (D) It depends on the specific circumstances. The answer to this question is: B. Platinum resistors have a temperature range of -200 to 850°C. The advantages of metallic platinum include good chemical stability, resistance to high temperatures, and the ease of obtaining pure platinum. Its high resistivity (p in Ω·mm2/m) allows resistors to be made using less material. Additionally, it offers a wide temperature measurement range. Its drawback is that in a reducing medium, especially at high temperatures, it is easily contaminated by steam derived from the oxidation compounds, which makes the platinum wire brittle and alters the relationship between resistance and temperature. Copper resistors have a temperature range of -50 to 150°C. Copper thermal resistors are inexpensive and offer good performance; they are widely used in industry within the range of -50 to +150°C. Copper thermistors are sensitive to humidity, prone to corrosion, and have a low melting point.