Unipolar charge induction on moving parts in static field

Floating metal objects, such as microelectronic devices are charged very easily under movement conditions in the static field instead of a static state (stop). The induced charge is assumed to be a same polarity in any part of metal object. According to a series of charge/discharge experiment, the magnitude of the induced charge is depending on 2 major parameters. They are: (1) relative velocity (v); and (2) static field gradient (dE/dx). To explain these phenomena, a unipolar charge induction model under dynamic conditions is discussed.