A detection circuit for an alternator regulator, and method therefor. The detection circuit comprises an input circuit arranged to receive a phase signal from an alternator regulator and to output an attenuated sense signal representative of the received phase signal, a detection component operably coupled to the input circuit and arranged to receive the attenuated sense signal output by the input circuit, and a blocking capacitance operably coupled between the input circuit and the detection component and arranged to block a DC component of the attenuated sense signal. The detection component is arranged to compare the received attenuated sense signal to at least one reference voltage signal, and to output a signal representative of a frequency of the phase signal from the alternator regulator based at least partly on the comparison of the received attenuated sense signal to the at least one reference voltage signal.