A step-up transformer is an electrical device that increases (steps up) the voltage from its primary (input) winding to its secondary (output) winding while maintaining the same frequency. It consists of two or more windings wrapped around a common magnetic core. Here’s how it works:

  1. Primary Winding: This is the coil connected to the input voltage source. When an alternating current (AC) flows through the primary winding, it creates a changing magnetic field around the core.
  2. Magnetic Core: The magnetic core channels the magnetic field generated by the primary winding to the secondary winding, ensuring efficient transfer of energy.
  3. Secondary Winding: This is the coil where the increased voltage is induced. The number of turns in the secondary winding is greater than in the primary winding. According to the principle of electromagnetic induction, this difference in the number of turns results in a higher voltage being induced in the secondary winding.

Key Points

  • Turns Ratio: The voltage increase is proportional to the ratio of the number of turns in the secondary winding to the number of turns in the primary winding (Turns Ratio = NsNp\frac{N_s}{N_p}Np​Ns​​). If the secondary winding has more turns than the primary, the voltage is stepped up.
  • Power Conservation: In an ideal transformer, the power in the primary winding (input power) equals the power in the secondary winding (output power), ignoring losses (Power P=V×IP = V \times IP=V×I). Therefore, if the voltage is increased, the current decreases proportionally, and vice versa.
  • Applications: Step-up transformers are commonly used in power transmission to increase the voltage from power plants to high levels for efficient long-distance transmission. They are also used in various electronic devices and systems where a higher voltage is required.