| 摘要 |
PURPOSE:To measure an insulation resistance with high precision and high stability without requiring any complicate counting-back circuit by inputting the voltage developed across a resistance connected in series with the resistance to be measured to an A/D converter as a reference voltage. CONSTITUTION:A constant voltage E is applied from a constant voltage generator 4 is applied to the series circuit of the resistance 3 to be measured and the resistance 5 for current/voltage conversion connected to measurement terminals 1 and 2. The output voltage E of the constant voltage generator 4 is divided by voltage dividing resistance 6 and 7 and supplied as an input voltage E' to the input terminal IN of an integral type A/D converter 8. The voltage V0 developed across the resistance 5 for current/voltage conversion, on the other hand, is supplied to the A/D converter 8 as the reference voltage through an amplifier 9. Then, the output 10 of the A/D converter 8 is supplied to a digitla display device 12 through a decoder and driver 11 to display the resistance value RX of the measured resistance 3.
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