| 摘要 |
PURPOSE:To discharge quickly the charge charged to a capacitor and to avoid the resetting failure by adding a discharging circuit of the capacitor in case a power supply is cut. CONSTITUTION:A discharging circuit passed through a diode 14 is added for a capacitor 61 in case a power supply is cut. The capacitor 61 is discharged in a short time since the resistance level of the discharging path is low. The electrostatic capacity of the capacitor 61 is set smaller than that of a capacitor 60. Therefore the greater part of the output voltage of an AVR2 is applied to the capacitor 61 when the power supply is kept on. Thus the voltage of a series circuit of capacitors 60 and 61 has a sudden drop when the capacitor 61 is quickly discharged. A sufficient current flows to a resistance 7 when the voltage of a terminal 3 has a rise after the power supply is recovered. Then a pulse having the large peak voltage is produced at a terminal 4. This prevents the resetting failure. |
