The high frequency transformer is the most important part of the switching power supply. The switching power supply generally uses a half-bridge power conversion circuit. When working, two switching transistors are turned on in turn to generate a 100kHz high-frequency pulse wave, and then the high-frequency transformer is used to step down and output low-voltage alternating current.

Transformers and inductors are easily confused because they have the same physical shape. There is only one rule that can be distinguished between them, the transformer is marked with "QTK", and the inductor is marked with "QHP".