Fringing Field Effect of the Parallel Plate Capacitors with the Dielectric Material

The aim of this work is measuring capacitance with various factors, e.g. the dielectric material (air and DI water),  the radius (r = 12.0, 16.9, 22.1, 27.3, 32.3 mm.) and the distance (d = 3 and 5 mm.) between of conducting sheets.  A parallel-plate (PP) capacitor is assembled from two the aluminum sheets which are parallel to each other. There are two conditions for the dielectric materials, one the air-fully filled and the another the water 50% height of d as dielectric material.  The capacitance is determined using formula;   when the electric field is uniform distribution. From the results, the measured capacitances are in the same direction with the theory. However, the measured capacitances are higher than capacitance from theory because of the fringing field effect. The electric fields between of parallel plate were non-uniform when the area of conducting sheet is small or the ratio between the radius and distance between of conducting sheet (r/d) is less than 10.  This effect will decrease when the area of ​​the conductor plate was increases.