KAJIAN SIFAT DIELEKTRIK BUAH SEMANGKA DENGAN PEMANFAAT SINYAL LISTRIK FREKUENSI RENDAH

The study of watermelon-based dielectric on capacitive measurement on various water content have been conducted by the use of alternating current signal of low frequency as one of the direction for nondestructive quality determination. This is done so that the substances which have been tested can be re-consumed and will not leave any chemical residues on the human body. The measurements were done by the use of copper parallel conductor and Hi LCR Tester with dual probes (modified from four probes) and were measured on frequency under 10 kHz. The air and water have been used as dielectric material filler to calibrate the parallel plate standard (1 for the air and 78 fo water on DC signal). The dielectric constant of air was 1.01003 (matching with standard 1,00054) and 75.79661 for water at frequency under 1 kHz. The dielectric constant and capacitance of watermelon were decreased when the frequency singal was increased. The reduction of dielectric constant and capacitance is eksponential, especially at fekuensi under 1 kHz. The dielectric constant of watermelon at low frequency is quite big, while at frequency up to 20kHz experiencing the reduction. The determination of water content by capacitance or delectric constant has the best result on frequency of 1 kHz. The dielectric constant of watermelon kernel was twice as its husk. Keywords : Dielectric Constant, watermelon, water content