The present invention discloses a method for controlling transformer excitation cycles and a circuit for controlling the same, wherein the excitation cycle and the demagnetization cycle, which determine the rise and fall of the excitation current, are modified to prevent the coil from being saturated. The supplanting setup data may be stored in a data store that is accessible to the destination, and may be local or remote to either or both of the source and destination. At leas part of the liquid storing means is detachable to the housing for easy replenishment of the liquid. Protective tape is provided on a first region where the first board and the third board overlap, and in a second region where the second board and the third board overlap.