| 摘要 |
PROBLEM TO BE SOLVED: To enable prevention of the time of day from going out of order, even if a shock is applied, and attainment of size reduction and lowering of the capacity of battery, at the same time. SOLUTION: Impact detection resistances 141, 143 of an impact detection circuit 104 detect a counterelectromotive force of a step motor 105 generated by impact. The counterelectromotive force is amplified to have a predetermined period and chopper width by a waveform shaping circuit 118 for chopper amplification, and even a light impact becomes detectable. Inverters 145, 146 compares the impact detection signals S22, S23 with a threshold, and detects the impact when the threshold is exceeded. A control circuit 102 supplies lock pulses to the step motor 105 via signal lines AA, BB at impact detection, and brakes rotation of a rotor 162, thereby preventing the time of day of a second needle 106 from going out of order. COPYRIGHT: (C)2011,JPO&INPIT |
