ZHANG Banghong
(Jingdezhen Ceramic Institute)
Abstract: As a art of the rapid moisture teller to determine water content in body paste, capacitance sensors are used mainly in the light of dielectric constant large in water and small in material itself. As water content in the paste changes, it will cause a change in sensitive capacitance. In fact, the reason is not the change taking place in dielectric constant of material or water. It is the volume proportion of water to material that causes the change. The capacitance formed by water and material can be expressed as Cs = f(B) and CL= f(1 - B) respectively, B representing the percentage of water content in volume. Sensitive capacitance Cx actually consists of Cs and CL Cx = Cs + CL). Further analysis shows that sensitive capacitance of the paste consists of an unchanging capacitance CR (determined by dielectric constant of material) and a capacitance CR changing with the volume percentage B of water content in the paste, that is: Cx = CY + CLo . When CY = 0. 0884B, B has as a a li lmear relation iwith th sensitive capacitance, which can be expressed with a maths model B = bCy = bCx + bCLo.
Keywords: ceramic body paste, capacitance - sensors, circuit analysis