Differential current sensor

A differential current sensor adapted for measuring a differential current between a first electric current through a delivery conductor and a second electric current through a return conductor, in particular for a direct-current power supply system, comprising:

• a) a low-ohmic first current-sense resistor for measuring the first electric current through the delivery conductor, wherein the first current-sense resistor is arranged in the delivery conductor and the first electric current flows through the first current-sense resistor,
• b) a first measuring device with a first measuring transducer for measuring a first voltage drop over the first current-sense resistor,
• c) a first voltage reference for calibrating the first measuring device,
• d) a low-ohmic second current-sense resistor for measuring the second electric current through the return conductor, wherein the second current-sense resistor is arranged in the return conductor and the second electric current flows through the second current-sense resistors,
• e) a second measuring device with a second measuring transducer for measuring a second voltage drop over the second current-sense resistor,
• f) a second voltage reference for calibrating the second measuring device, wherein
• g) the first measuring transducer successively measures both the first voltage drop and the first voltage reference, and
• h) the second measuring transducer successively measures both the second voltage drop over the second current current-sense resistor and the second voltage reference.