Electra is a 2D and 3D electrical tomography and induced potential measuring instrument with high Signal amplification and digitization performed where the signal is produced (i.e. at the electrodes) and this allows higher data quality and extremely low current intensity in the soil, minimizing power requirements and artefactual polarizations. Weight and size are orders of magnitude lower than the traditional systems. Electra injects alternate current into the soil, which allows a higher velocity and precision in the acquisition process, eliminating signal stabilization dead time and induced polarization of the electrodes. The outstanding feature of Electra is the synchronous and simultaneous acquisition on all channels, both active and passive. This implies a knock down of measurement time in several configurations. Electra, can record data with no duration limits, which is particularly important for the spontaneous potential acquisition. Acquisitions possible with Electra: - Spontaneous potentials (no recording time limit) - Induced polarization - Wenner, Schlumberger, pole-pole, dipole-dipole - Other configurations