| 摘要 |
PROBLEM TO BE SOLVED: To provide a leak detector which can detect low leak resistance without raising the measured frequency or the capacity of a capacitor. SOLUTION: The leak detector 20 impresses the rectangular waves of constant voltage amplitude from the output port of a microcomputer 5 to between a group of batteries 1 and a chassis ground via a capacitor 3, and measures the current flowing in the capacitor 3 thereby detecting the leakage between the car body and the group of batteries 1. To measure the current flowing in the capacitor 3, the output from the output port of the microcomputer 5 is connected to the positive-phase input of an operational amplifier 11, and the output of the operational amplifier 11 is connected with the capacitor 3 via a resistor 11 for current detection, and besides the junction between the capacitor 3 and the resistor 11 for current detection is connected to the reverse-phase input of the operational amplifier 11, and further the voltage across the resistor 11 for current detection is inputted into the differential amplifier which is composed an operational amplifier 16 and resistors 12-15, and the output voltage of the differential amplifier is detected. COPYRIGHT: (C)2007,JPO&INPIT
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