| 摘要 |
PURPOSE:To stop a minute hand at the position of zero second every minute at the time of resetting of a frequency-dividing circuit by driving a step motor for 30sec motion of the hand through the intermediary of a NOR circuit on which a frequency-dividing output and a reverse frequency-dividing output which are subjected to the integrating processing respectively are impressed. CONSTITUTION:When a switch 8 is connected to a contact point 8a, a 1/30Hz signal of a frequency divider 3, passing an inverter 9 and another inverter 4, is turned to be the frequency- dividing output of an original phase through inversion and reinversion, and further subjected to the integrating processing in integrating circuits 10 and 11 and then is impressed on the NOR circuits 10 and 12. By this, driving pulse trains e and g which have the cycle of 1/30Hz and different phases are added from the circuits 10 and 12 to the bridge inverter 5 of the step motor 6 and the motor 6 is driven by the pulse train j which is different in polarity. When the polarity of the motor 6 is selected so that the minute hand indicates the zero second every minute when the pulse train e is generated, the minute hand indicates zero second every minute on condition that the switch 8 is connected to the contact point 8c, the circuit 3 is reset and the motor 8 is stopped. Accordingly, the discrimination of the position of the minute hand when the hand is adjusted becomes easy and sure. |
