A linear variable differential transformer(or transducer) is actually a transformer whose core moves with the distance measured and that outputs a variable analog voltage as a result of this displacement. In general, a transformer is an electric-to-electric energy converter that changes the voltage/current ratio.Except for losses, the total input energy to the device is the same as the total output energy. As a transformer increases or decreases a voltage in proportion to the number of turns in its coils,the corresponding current changes inversely with it.