A method of measuring an electrical characteristic of a current path is disclosed. In one aspect, the method includes a probe for scanning spreading resistance microscopy (SSRM), a test sample contacted by the probe, a back contact on the test sample, a bias voltage source and a logarithmic SSRM amplifier, when a modulation at a predefined frequency is applied to either the contact force of the probe or to the bias voltage, the device comprising electronic circuitry for producing in real time a signal representative of the electrical characteristic, according to the formula lognA=±VSSRM±logn(dV)+Vmultiplier.