High-frequency transformers are mainly used as high-frequency switching power supply transformers in high-frequency switching power supplies, and are also used as high-frequency inverter power supply transformers in high-frequency inverter power supplies and high-frequency inverter welding machines. According to the working frequency, it can be divided into several frequency ranges: 10kHz-50kHz, 50kHz-100kHz, 100kHz~500kHz, 500kHz~1MHz, and above 1MHz. In the case of relatively large transmission power, power devices generally use IGBTs. Due to the tailing phenomenon of the turn-off current of the IGBT, the operating frequency is relatively low; if the transmission power is relatively small, MOSFETs can be used, and the operating frequency is relatively high.