| 摘要 |
PURPOSE:To prevent a current from increasing excessively even in case when a switch is held in an on-state by mistake, and also to prevent a malfunction caused by a noise, by opening and closing a switching element by an output signal of a timer. CONSTITUTION:In a correcting mode, when a crown 3 is rotated, a switch 6 repeats on and off intermittently, and while it is on, a switch input terminal SW becomes VDD potential through the switch 6, and an output of a chattering preventing circuit 12 also repeates ''1'' and ''0''. As a result, a correcting signal is supplied to a clock circuit 8 from a correcting circuit 13, the display is corrected, also while an output of the circuit 12 is ''1'', an output of an invertor 15 becomes ''0'' and reset of a timer 14 is released, and operation of the timer is started by counting of a clock CL. Subsequently, when measurement of the timer 14 ends, an MOSFET 11 is opened by its inverted output, a low resistance 10 is detached from an electric power supply terminal VSS, a current flows to the terminal SW through a high resistance 9, and waste current consumption of a battery 5 is prevented. |
