| 摘要 |
PURPOSE:To obtain the true resistance value of a resistor to be measured irrespective of the value of cable resistances by subjecting the resistor to be measured to a constant current and constant voltage excitation and storing the respective output voltage then measuring the resistor through operation processing. CONSTITUTION:When switches S1, S2 are opened and a driver circuit 12 excites R by the constant electric current I=E/R, a voltmeter 3 indicates e2=RI+rI. Next, when the switches S1, S2 are closed and the driver 12 excites the R by the constant voltage value E, the voltmeter 3 indicates e3=[(R+r)/(R+2r)] E. If a cable resistance (r) is erased by using te values e2, e3, the value of R is determined as R=(e2/I)X[2-(E/e3)]. Hence, the e2, e3 are temporarily stored in two memories 9, after which the operations conforming the above-mentioned equation is carried out by an oprator 10 and the results are displayed by a display device 4, whereby the true resistance R is measured without being affected by a cable resistance (r). |
