This Small Business Innovation Research Phase I project will demonstrate the feasibility of a solid state relay using Giant Magnetoresistance Ratio (GMR) materials and new advances in solid state power devices. A current input through a current strap or integrated inductive winding is electrically isolated from a GMR sensor to a stand-off voltage of 1000 Volts to 2500 Volts, and the sensor detects the magnetic field produced by the input current. Magnetic field from the input current is enhanced by magnetic material, which also reduces risk of false turn-on due to spurious external magnetic fields. Integrated circuits and power devices, including an FET-controlled SCR, can be used to accomplish the current handling function of a solid state relay, in addition to other electronic functions requiring isolation. GMR materials can be configured as a sensor to simplify the function of isolation compared with opto-isolation or using conventional magnetoresitive materials, and are potentially much faster, more reliable, and lower cost than present technology. Phase I will demonstrate the device in hybrid form and Phase II will demonstrate a totally integrated device.