| 摘要 |
PURPOSE:To suppress the transient current low at the time of turn-on of a power switch, by providing a relay coupled in parallel with input terminals and providing a resistor which is connected in series with a capacitor and is opened or closed by a relay contact. CONSTITUTION:The contact 8 of the relay 6 is open when no voltage is applied across the input terminals 11, 12 of the low-pass filter circuit 9 and is closed when a voltage is applied across the input terminals. When the switch 3 for a DC power source 1 is turned on, the contact 8 remains open until the relay 6 operates against the inertia. Since the resistor 7 is connected in series with the capacitor 5, the charging current of the capacitor 5 is suppressed low by the appropriately set resistance of the resistor 7. Thereafter, the relay 6 operates and the contact 8 is closed. The operation of this low-pass filter circuit becomes same as that of conventional low-pass filter circuit at the time when the resistor 7 is short-circuited. Thereby, the transient current is suppressed low and the saturation of the magnetic flux is eliminated. Therefore, a coil 4 can be miniaturized. |
