一种基于有源电桥的电容式粮食水分传感器

Capacitive moisture sensor for grain based on active bridge circuit

在传统电桥电路的基础上,设计了一种有源电桥的电容式检测电路。该电路具有灵敏度高、线性范围宽的特点。将其用于粮食水分的检测,实现了一种具有线性特性的粮食水分传感器。通过试验测试粮食的电阻抗特性,尤其是电容特性与粮食水分之间的关系,确定了电路的工作频率。试验结果表明:这种粮食水分传感器的输出电压与粮食水分之间呈良好的线性关系,可满足粮食水分在线检测的要求。

Based on the traditional bridge circuit, an active bridge circuit, which performs high sensitivity and good linearity, is designed for capacitance measurement. When it is utilized for grain moisture measurement, a linear grain moisture sensor is implemented. By experimentally measuring the relationship between the characteristics of the impedance, especially the capacitance, and the grain moisture, the working frequency of the measurement circuit is determined. The preliminary experimental results indicate that the output voltage of the sensor is good linear with the grain moisture and can fulfill the online moisture measurement requirement for grain.