This experiment is to determine the secondary voltage in open circuit transformer, the short-circuit in secondary side and the primary current with transformer loaded. A transformer is an electrical device that transmits energy between two circuits via electromagnetic induction. The basic functioning components of the transformer are two coils twisted around the same core and electrically insulated from one another. Faraday's law states that the alternating current (AC) source generates an alternating flux in the core, which generates an AC in the primary and induces an emf in each coil. This experiment consist five parts where part I and II connected as an open transformer. Part III and IV connected as short-circuited transformer and part V was set up as loaded transformer. Each part took three recordings to get more accurate result. All the graph showed directly proportional graph but graph for part IV have slightly further from expected result. The possible causes may be accidental error and systematical error. To get more good results, it is advised to read accurately and use accurate equipments. Although voltage and current step-up and step-down are typically done with transformers, they can also be used to separate electrical systems.