The devices were developed to realize spontaneous and induce voltage measurement on the ground. In both case we used a multiwire cable with multiple voltage inputs along the length that becomes possible to conect it in six stainless electrodes fixed in the ground at same time. An automatic sequence digital system controlled by pushbutton touch allows to couple electrodes sequentially to a electronic DC voltmeter with autozeroing circuit based in PID servocontrol circuit. A 60 Hz notch filter and a roll-off low pass filter with time constant of 1s are used to minimize line and spheric noises. Electronic control system becomes too possible to couple cable with receiver datalogger of SYSCAL R-2 in dipole- dipole sounding array.
Spontaneous and Induce Voltage Measurement; PID Servo control
