A switching power supply apparatus for controlling the operation of a switching FET adapted for switching a rectified smoothed output of a primary side rectifying smoothing circuit by a switching controlling circuit having a hysteresis low-voltage mistaken operation prohibiting circuit. This compound is useful as an intermediate in the synthesis of toluidine blue O. Methods of the various embodiments facilitate fabrication of floating gate segments having dimensions less than the capabilities of the lithographic processed used to form the gate stacks.