| 摘要 |
PURPOSE:To obtain an operation type insulation tester high in voltage resistance and excellent in measuring capacity, by providing a current-voltage converter for selecting a gain corresponding to testing voltage for converting a current obtained by applying testing voltage to an object to be measured to a voltage value and a comparator for comparing and discriminating the output of said converter and the output made equivalent artificially of a comparing voltage generator. CONSTITUTION:A testing voltage power source 5 has the outputs of a single or a plurality of testing voltages V, V' required in measurement while said voltages are selected by a change-over device S to be applied to one terminal (c) of an object Rx to be measured through a relay circuit 3 and the other terminal (d) is connected to the reversal input terminal (-1) of a current-voltage converter 7 through a protection circuit 6. A comparing voltage generator 10 is one for artificially and equivalently generating the output voltage value of the current-voltage converter 7 to an insulation resistance value in the measuring range of the object Rx to be measured and is constituted of an operation circuit. A comparator 11 is mainly constituted of an operation amplifier C and the output of the comparing voltage generator 10 is connected to a non-reversal input terminal (+) while the output of the current-voltage converter 7 is connected to the reversal input terminal (-).
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