Switching power supply is through the circuit control switch tube for high-speed channel and cut off, direct current into high frequency ac power supply to transformer transformer voltage, so as to produce the required set or more sets of voltage! The reason for switching to huawei hf ac is that the efficiency of hf ac in transformer transformer circuit is much higher than 50HZ. So the switching transformer can be made very small and not very hot when working!!The cost is very low, if you do not change 50HZ to high frequency then the switching power supply is meaningless!! The switching transformer is not a mystery, just an ordinary transformer!This is the switching power supply.Switching power supply can be divided into isolation and non - isolation two, isolation must have a switching transformer, and non - isolation may not necessarily have.