| 摘要 |
PURPOSE:To measure simultaneously an insulation resistance with another operation without looking at a display by detecting a decrease in insulation resistance or the extent of the decrease from whether a sound is generated or not and further variation in its intermittent frequency. CONSTITUTION:A resistance 3 to be measured is connected to measurement terminals 1 and 2 and a voltage is applied from a constant voltage generator 4 to flow a current to the resistance 3 to be measured. This current is converted by a current/voltage converting circuit 5 into a voltage signal, which is supplied to an indicator 7 through an amplifier 6. A comparator 8, on the other hand, is supplied with a voltage set by a variable resistor 9 as a reference level Vref and when the resistance value of the resistance 3 decrease below a specific value, an electronic buzzer 10 as a sounding means is driven with the output of the comparator 8, so that the operator recoginizes the decrease in insulation resistance.
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