An electrode for use in the electrical investigation of a medium such as a borehole wall, comprises a sheet (32) of electrically resistive material having opposed first (34) and second (33) surfaces, one or more elongate electrical conductors (35,36) of low resistivity, an end face of each conductor...http://www.google.com/patents/US5162740?utm_source=gb-gplus-sharePatent US5162740 - Electrode array construction featuring current emitting electrodes and resistive sheet guard electrode for investigating formations along a borehole
