| 摘要 |
PURPOSE:To enable the hand display of a split time in a figure below a second order, by stopping the driving of a step motor when the content of a clocking counter and hand display are not coincided during calibration. CONSTITUTION:When a switch 3 is closed, a switch 6 is opened to calibrate a 20Hz signal by a clocking counter 8 while the 20Hz signal passing a gate circuit 12 is selected as a drive pulse to count the same by a hand position counter 11 and a high level coincidence output is outputted from a coincidence circuit 10 while a 1/20 second hand 16 is driven by a step motor 14. When the switch 3 is opened, the hand 16 is driven corresponding to the calibrated second time latched by a latch circuit 9. By this mechanism, the contents of the counters 8, 11 come to non-coincidence and the output of the circuit 10 is reversed to a low level to cut off the 10Hz signal through the circuit 12 while a split time below a second is displayed by the hand 16. |
