There is described herein methods and systems for detecting electrically-conductive particles (chips) in fluid of an aircraft engine. The method comprises applying a plurality of excitation currents Ii across a magnetic chip detector mounted to a fluid system of the aircraft engine and measuring a corresponding plurality of resistance values Ri, where i is an integer that varies from 1 to N, and where N corresponds to a number of different excitation currents applied across the magnetic chip detector. The method further comprises determining a chip size indication Y from the plurality of resistance values Ri, and detecting a chip in the fluid when the chip size indication Y exceeds a threshold Ythres.