| 摘要 |
PURPOSE:To prevent troubles in warning and display, by operating a power source switch for a specified time period, testing sounding and display of a sounding body and display lamps, thereby providing testing functions in the power source switch. CONSTITUTION:When a power source switch 10 is depressed for a short time, a power switching circuit 11 is operated, and power is supplied to the entire control circuits. When the switch 10 continues to be depressed for a specified time period (e.g., three or more seconds), a capacitor C1 is charged and a comparator I17 comes to an H level. Then a timer circuit 12 is turned ON. As a result, a transistor Trs is turned ON and a buzzer BZ is sounded. Clock pulses from an oscillating circuit OSC are received, and a light emitting diode D1 performs scanning display. Since the testing functions are provided in the power source switch 10, troubles in warning and display can be prevented.
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