電容式傳感器利用油與水介電常數(shù)差別較大的特性,可測出油品中水的質量分數(shù)。從物質分子結構的特征出發(fā),探討傳感器的工作原理,分析在交變電場作用下水與油的極化過程以及交變電場頻率對極化強度的影響。得出在交變電場頻率為10MHz 時,油與水的介電常數(shù)差別最大,因而將10MHz 作為傳感器的工作頻率,可獲得最高靈敏度。
關鍵詞: 位移極化; 取向極化; 中性; 極性; 電荷密度
Abstract : The capacitive sensor can measure the mass fraction of water in oil through the great different of di2 electric between oil and water. The mechanism of capacitive sensor and the polarizing process of water and oil in alternating electric field and the influence frequency on the strenth of polarization is discussed depart from molecule structure. At the same time it will be pointed out that the difference of dielectric between oil and water is the greatest when the frequency of alternating electric field is 10 MHz. Therefore if the working frequency of
the sensor is 10 MHz ,it can attain the highest sensibility.
Key words : movement polarize ; orient polarize ; neuter ; polarity ; charge density