To provide a rotation
detector capable of executing more stable rotation position detection
processing.SOLUTION: The rotation
detector 1 includes a
magnet 10 rotating together with a rotation shaft 11, a power generation circuit 20 having a power generation element 21 generating power by utilizing the large
Barkhausen effect, a magnetic sensor 41, an
information processing part 42 detecting the rotation position of the rotation shaft 11, and a power supply part 30 supplying power to the magnetic sensor 41 and the
information processing part 42, the power generation circuit 20 includes a first
power storage part 23 storing power generated by the power generation element 21, a second
power storage part 26 for storing power, and a
power storage control part 27 controlling charging and discharging according to the
voltage of the first power storage part 23 and the
voltage of the second power storage part 26, the first power storage device 23 supplies power necessary for the rotation position detection
processing to the
power supply unit 30. At the end of the rotation position detection
processing, the second power storage device 26 stores part of the power remaining in the first power storage device 23 before the first power storage device 23 is discharged to the outside in the
discharge processing.SELECTED DRAWING: Figure 1