Isolation transformer is the transformer with electrical isolation between the input winding and the output winding. Isolation transformer is used to avoid users accidentally touching the charged body at the same time. Isolation transformer, whose transformer ratio is usually 1:1, is a special transformer with high insulation strength between the primary winding and secondary winding to isolate different potential to suppress common mode interference. The main function of the step-up & step-down isolation transformer is to completely insulate the primary side and the secondary side, and also to isolate the loop. In addition, the high frequency loss of the iron core is used to suppress the high frequency clutter into the control loop.