  We show here a mesoscopic device based on a narrow ring containing an
electron. In the device, an amount of energy is stored in advance. Similar to
the pendulum, an exact periodic motion of the electron is thereby initiated
afterward. The motion appears as a series of sharp pulses, and is in nature
different from the well known Aharonov-Bohm (A-B) oscillation. In particular,
the pulses of current can be tuned to be very strong (say, more than two orders
stronger than the usual A-B current). Related theory and numerical results are
presented.
