Temperature acquisition method of NTC.5.8G Frequency microwave sensor module

　　In the low-cost temperature measurement scheme, a pull-up resistor is generally connected in series between the NTC thermistor and the positive pole of the power supply, and the ambient temperature is determined by collecting the voltage division changes across the NTC thermistor. The commonly used temperature measurement circuit is shown in the figure below, R2 is an NTC thermistor, R1 is a pull-up resistor, and the power supply voltage is 5V.

　　Combining Ohm's law - series voltage divider and NTC thermistor calculation formula to deduce: T1=(B*T2)/(ln(10*V/(5-V)/R)*T2+B)

　　Taking the product mentioned above as an example, two schemes, RT look-up table method and formula derivation method, are used to convert the collected voltage value into temperature, and the errors of the two schemes are compared. As shown in the figure below, the red frame is circled. Between the temperature range (80℃~0℃), the error value between the temperature calculated by the formula and the table look-up method is within 0.5℃, and the error is larger in other intervals. Therefore, if the error temperature is to be collected accurately, the RT look-up table method is more accurate.

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