GE IC866-0900-4A3-5P是一款温度变送器，通常用于工业过程控制和监测中。

温度变送器一般由基准源、冷端补偿、放大单元、线性化处理、V/I转换、断偶处理、反接保护、限流保护等电路单元组成。它是将热电阻产生的电阻经冷端补偿放大后，再由线性电路消除电阻与温度的非线性误差，后放大转换为4～20mA电流输出信号。为防止热电阻测量中由于断丝而使控温失效造成事故，变送器中还设有断电保护电路。当热电阻断丝或接解不良时，变送器会输出大值（28mA）以使仪表切断电源。

It is a temperature transmitter commonly used in industrial process control and monitoring.

Temperature transmitters are generally composed of reference sources, cold junction compensation, amplification units, linearization processing, V/I conversion, couple breaking processing, reverse protection, current limiting protection, and other circuit units. It amplifies the resistance generated by the thermal resistor through cold end compensation, and then eliminates the nonlinear error between the resistance and temperature through a linear circuit. After amplification, it is converted into a 4-20mA current output signal. To prevent accidents caused by temperature control failure due to wire breakage in thermal resistance measurement, the transmitter is also equipped with a power outage protection circuit. When the thermal resistance wire is broken or poorly connected, the transmitter will output a high value (28mA) to cut off the power supply of the instrument.