Abstract:A new nonlinear equivalent circuit was proposed to describe the mineral-electrolyte interface when the nonlinear system being neared to equilibrium state, i. e, the induced current density is not very high. The Volterra/Winner nolinear system theory was employed to analyse the equivalent circuit. A mathematical formula to calculate overvoltage response of the circuit to arbitrarily induced current has been obtained, and cathode/anode polarization curves of pyrite and graphite were calculated theoretically with the formula. Comparision of these curves with experiment results showed that the proposed equivalent circuit is suitable to describe the nonlinear system composed of mineral-electrolyte,it can be usedto study the nonlinear effect of spectral IP.

Key words: spectral IP; nonlinear effect; equivalent circuit; admittance; anode/cathode polarizaTion