Power Transformer is a static device used for stepping down or stepping up the voltage from one circuit to another at the same frequency. These are used to transmit electrical power from one place to another while keeping the transmission losses at minimum. The electrical power is stepped up to higher voltage at the source end and is stepped down to the utility voltage at the point of application. The higher the voltage, the lower are the losses during transmission. These are designed to have highest efficiency at full load. These are massive in size and too bulky.