Abstract: A low current detector using magnetoresistive sensor is used in a ground fault detector that opens a current carrying circuit when an unbalanced or dangerous condition occurs in the circuit. The current circuit has windings wrapped around a toroidal member of magnetic material having a cross sectional gap. First magnetic flux lines induced in the toroidal member by the circuit project from the gap toward a permanent magnet having second emergent magnetic flux lines that bend the first flux lines in a flux line mesh zone when an unbalanced current exists in the current carrying circuit. The flux lines are non-existent in the gap of the toroidal member when the circuit is in a balanced or non-fault state. A magnetoresistive sensor is disposed in the mesh zone in a position producing a signal indicative of an unbalanced condition caused by a current fault. A circuit breaker, connected to flux sensor responds to the signal indicating an unbalanced condition by opening the circuit.