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本文介绍一种已经成功地用于混凝土和土壤中含水量测定的仪器。该仪器采用平板电容器作为检测传感器。待测样品作为介质,填充到平板电容器中。由于水的介电常数(为81)远高于待测物的介电常数(混凝土或土壤的介电常数在2～5范围),因而含水量的较小变化将极大地引起待测物介电常数的变化。介电常数的这种变化用电容传感器进行检测,检测出的电容变化量在桥路中测定,接着予以放大、滤波、整流、记录和读出,完成含水量测量过程。
This article describes an instrument that has been successfully used to determine water content in concrete and soil. The instrument uses flat-panel capacitors as the detection sensor. Test sample as a medium, filled into the plate capacitor. Since the dielectric constant of water (81) is much higher than the dielectric constant of the material to be measured (the dielectric constant of concrete or soil is in the range of 2 to 5), small changes in water content will greatly affect the DUT Electricity constant changes. This change in dielectric constant is detected by a capacitance sensor. The detected change in capacitance is measured in the bridge and amplified, filtered, rectified, recorded, and read out to complete the moisture content measurement process.