As a continuation of the work presented in [18] and [19], this paper proposes, theoretically analyses and experimentally evaluates a direct interface circuit for inductive sensors with a variable self-inductance. In the proposed circuit, the inductive sensor is excited by a single step pulse and the result of the measurement is the inductance value at low frequencies; this is assuming that the frequency dependence of the inductance (due to the frequency dependence of the permeability) starts decreasing at high enough frequencies. For this reason, the proposed circuit is not suitable for those inductive sensors whose operating principle involves the measurement of the inductance at medium–high frequencies; this is the case, for instance, of eddy-current sensors that are generally excited by an AC signal of high frequency (say, units or tens of MHz) so as to have an appropriate penetration depth in the metallic target to be detected [20] and [21]. Furthermore, the sensor is expected to have an inductance of some units or tens of millihenry [3], [4], [6] and [7]; lower values of inductance would require a very high speed reference oscillator that is not feasible nowadays in common low-cost 8-bit microcontrollers.