基于电容法的木材含水率检测传感器设计

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中图分类号：S781.33 文献标识码：A 文章编号：2095-2953（2025）07-0071-05

Design of Wood Moisture Content Detection Sensor Based on Capacitance Method

YANG Kang， XU Hua-dong *

（CollegeofElectricalandMechanicalEngineering，NortheastForestryUniversity，HarbinHeilongjiang15O4，Chin：

Abstract：The moisture content of wood changes various properties of wood，which affects itsperformance and life span.In order to measure the moisture content of wood in a simple and efective way，a wood moisture sensor based on the capacitance method has been designed. This sensor measures the capacitance of the probe to reflect the change of moisture content bymeasuring the frequencyof theresonant signal.Firstly，the detection circuit is designed with theoscilatorchipas thecore，with the stainless steel nail as the probe，two paralelnails are approximatedas the twopoleplates of the parallel-platecapacitance，and the distance and length between the nails are fixed， andunder this circumstance，themagnitudeof thecapacitance of the probe isonlyrelated to the dielectric constant of the medium between thenails.Next，the measurement feasibilityofthesensor is analyzed，including the accuracy of the detection circuit and the dynamic response time，and the capacitive resistance characteristics of the probe. Then the wood block with 10%-80% water content is used for calibration，and the calibration formula of the water content of the wood block and the frequency ofthe resonant signal are found out.The efect of temperature on the sensor is also analyzed.The experiment proves that the accuracy of the detection circuit is 99 % ，the dynamic response time is 80ms- 200ms ，and the probe capacitance varies linearly with the moisture content of wood. The calibration formula is f=0.0072x2+0.52x-2.33 .The error of measuring wood moisture content is between -7. 55% and 2.44%

Key words：wood moisture content；dielectric constant；parallelplate capacitance；LC oscilating circuit; resonant frequency

木材的应用十分广泛，包括家具、建筑、声乐设备、生物化学研究等，其中影响木材性质的主要因素就是木材含水率。（剩余5369字）