The usage of high voltage in electrical transmission systems reduces the power losses; on the other hand, raises the insulation problems. To overcome the problems of electrical insulation depends on the development of insulation materials and systems. Experimental studies play an important role in the development of insulation systems. Design and implementation of components used in experimental studies, are very difficult, time consuming and therefore higher costs. In this study, the production of a liquid resistor, using CuSO(4)5H(2)O (copper (II) sulfate pentahydrate) solution treated with ultrasonic bath and vacuum technique, is described. The produced liquid resistance can be prepared easily compared to that obtained by conventional methods and its value can be changed. Experimental results show that, the liquid resistance exhibits low partial discharge levels less than 0.1 pC, at pure sinusoidal and at voltages containing 3rd and 5th harmonic components. On the other hand, it is not recommended to use the liquid resistance under DC conditions.