Step-up transformers are used for

A step-up transformer is an electrical device designed to increase the voltage from a lower primary level to a higher secondary level. This is achieved by having more turns of wire in the secondary coil than in the primary coil. According to the principle of electromagnetic induction, while the voltage increases, the current decreases proportionally to conserve power, neglecting minor losses. This function is critical in power systems, where step-up transformers are used at generating stations to raise voltage for long-distance transmission. High-voltage transmission is preferred because it minimizes energy loss due to resistance in the power lines. Therefore, the primary purpose of a step-up transformer is to increase voltage, not to increase electrical power, as power remains constant in an ideal transformer.