電容式感測器可以根據介電常數檢測材料介電特性。為了監測放電加工介電油中侵蝕顆粒的介電材料,本研究提出了一種新型的圓柱形平行板感測器。感測器系統具有高靈敏度和良好的電路穩定性,可用於測量小濃度。該研究成功地測量了介電材料,例如活性炭和炭黑粉末,其濃度範圍為0.2g / 100ml至5g / 100ml。該研究還成功地測量了0.5g / 100ml至3g / 100ml的鐵粉濃度。本研究並成功地測量了放電加工機介電油中的介電粒子。五分鐘的測量驗證了本感測器的穩定性。;A capacitive sensor is a basic capacitive coupling that can detect and measure material dielectric particle, based on their dielectric constant or conductivity. To detect and monitor the dielectric materials of the eroded particles in electrical discharge machining (EDM) oil, this study present a new type of parallel plate sensor with a cylindrical shape. The sensor system present high sensitivity of sensor and good stability of signal conditioning circuit for measuring small concentrations. This study successfully measured dielectric materials such as activated carbon and carbon black powder with a concentration range from 0.2 g / 100 ml to 5 g / 100 ml. Also, this study successfully measured the concentration of iron powder from 0.5 g / 100 ml to 3 g / 100 ml. This study also successfully measured dielectric particles in the EDM machine dielectric oil. Five minutes measurement indicates the stability of sensor measurement.