Abstract: A high frequency power transformer having a multi-element magnetic shield conforming to the surface of the structure including provisions for specific features of the magnetic circuit and winding assembly. The winding is disposed on one side of a four-sided magnetic circuit and is partially surrounded by a close fitting electrically continuous loop. The winding assembly includes an area having a higher electrostatic field and is surrounded by a second electrically continuous loop which is spaced apart from the winding assembly, providing significant electrostatic shielding and air movement over the winding assembly while avoiding arcing between the shield and the winding assembly due to the high electrostatic field.

Abstract: A power supply operable from power mains voltages generally within two voltage ranges according to which the power supply automatically switches between a full wave and a voltage doubler. Furthermore, the power supply provides automatic mode selection on a cycle-by-cycle basis, sensing the mains signal during an initial portion of the mains input cycle and causing the power supply to select a mode of operation during that cycle. Thus, the present invention provides rapid response to changing mains voltages. Moreover, the voltage doubler mode is inhibited during the initial power up period, providing a margin of safety when initially energized or when connected to rapidly changing mains voltages.