MEASURING DEVICE OF RESISTIVITY

摘要

PURPOSE: To provide a resistivity measuring circuit capable of expanding a range of resistivity measurement, enhancing the accuracy of the measurement and reducing a cost of a resistivity measuring device. CONSTITUTION: A resistivity measuring circuit comprises a constant current power source circuit 11 that supplies a constant current (i) to a specimen 14 to be measured in the measuring of the resistivity and a voltage measuring circuit 12 that measures an output voltage from the specimen 14. It further comprises a common power source circuit 13 that commonly supplies a DC voltage to the constant current power source circuit 11 and voltage measuring circuit 12. The voltage measuring circuit 12 comprises a differential amplifier 15 which is connected to a measuring terminal of an output voltageΔe from the specimen 14 and a constant voltage circuit 17 that supplies a constant voltage to a power source terminal of the differential amplifier 15. The constant voltage circuit 17 is connected to a terminal of the common power source circuit 13 via a constant current circuit 19.