| 摘要 |
PURPOSE:To make it possible to remove the noise of the inductive voltage or the thermoelectromotive force for counting out the correct resistance value by making to flow the chopped constant-current to a sample for taking the difference in the potential difference of both ends of the sample at the time of conduction and nonconduction of the current. CONSTITUTION:The current is made to flow from the constant current source 2 through a chopper 3 to the sample 1. The potential difference taken out through the lead wire 4 is held by the sample hold circuits 6-1 and 6-2 through the amplifier 5. From the signal held by the SH circuit the portion of DC of the inductive voltage is eliminated by taking the difference through the substraction circuit 8. For avoiding the output of the spike noise of FET of the SH circuit the sampling signal (d) of the AD converter 9 is set so that the phase thereof forwards than the timing signals (b) and (c) to be controlled by the timing logic circuit 12. The output of the AD converter 9 is put out to the recording terminal 11 through the DA converter 10. |
