Coil-Free GFCI Using the World’s Most Sensitive Magnetometers 

We demonstrate sub-milliamp current detection using NVE’s ultrasensitive GMR and TMR magnetometers. The magnetomerters have enough resolution for a coil-free Ground-Fault Circuit Interrupter (GFCI).
Unlike inductive, coil-based solutions, NVE's sensors are ultraminiature and inherently DC-correct, enabling higher-performance solutions to the most demanding current sensing requirements.
With sensitivities as high as 500 mV/V/mT, NVE magnetometers are as sensitive as coils, and can precisely measure fields of less than a microtesla.
Here is a link to more information about the TMR magnetometer used in this demo:
www.nve.com/we...
And the GMR magnetometer we demonstrated:
www.nve.com/we...