Fluxgate based current transducer for measuring a primary current flowing in a primary conductor, comprising a fluxgate magnetic field detector and a measuring circuit. The fluxgate magnetic field detector includes an excitation coil driven by an oscillating excitation current (Ifluxgate) supplied by the measuring circuit. The measuring circuit is configured to provide a first and a second measurement output of the oscillating excitation current. The transducer further comprises a signal output processing unit for comparing in real-time the first and second measurements outputs, wherein the signal output processing unit is configured to send an error signal output if the difference between said first and second measurements outputs exceeds a tolerance value.