| 摘要 |
PURPOSE:To prevent any increase in electric current consumption in the continuation of turned-ON state of a detection switch. CONSTITUTION:A voltage is applied to one edge of a detection switch 6 by a charging circuit 14. The gate of an FET Q1 is connected through a resistor R2 to the other edge of the detection switch 6. A resistor R3 is connected between the gate and source of the FET Q1. When the detection switch 6 is turned ON, the FET Q1 is turned ON by the charged electric load of a condenser C1, and a one-shot multi vibrator 15 is triggered. The gate of the FET Q2 is connected to the charging circuit 14. When reset is applied by the output of the one-shot multi vibrator 15, a CPU 16 sets the source to a ground electric potential, and puts the FET Q2 in a turned-ON state. The drain electric potential of the FET Q1 at this time is detected, so as to detect the turned-ON state of the detection switch 6. The divided voltages of the resistors R1-R3 are set lower than the turned-ON voltage of the FET Q1. |
