Fig. 11From: A procedure for stable electrical measurements on a rock sample against high contact resistance as a prerequisite for electrical tomographyA scheme of measurement for the cylindrical plastic samples. z and θ are coordinates as defined in Fig. 10. RIN is input resistance, RV is insulation resistance between the negative terminal and chassis ground, HI labels positive terminals, LO labels negative terminals, C1 and C2 are current electrodes, and P1, P2, P3, P4, P5, and P6 are potential electrodes. The DC source (Model 6243, ADC; Saitama, Japan) injected a known constant current. An ammeter (Model 3458A, Keysight; Santa Rosa, California, USA) monitored the injected current. Electrometers (Model 6514, Keithley, Cleveland, Ohio, US.) with RIN = 200 TΩ acted as the voltmetersBack to article page