The invention provides a compact and highly reliable electronic apparatus that can be driven by a small-capacity battery, and that can achieve high-speed continuous driving of a load by quickly judging the recovery state of the battery after driving the load. The winding structure includes a ring-shaped core with a gap, a first coil and a second coil wound around the core. An upper thigh cuff attaches at opposed ends to the upper end portions of the two vertical struts whereas a lower shin cuff attaches at opposed ends to the lower end portions. This inverter develops a near sinusoidal approximation voltage waveform with fast switching and small low pass AC output filter. The linkage assemblies include separate linkage arrangements for horizontal and vertical displacement of the foot supporting members, and the linkage assemblies accommodate travel of the foot supporting members to positions laterally adjacent the cranks.