Apparatus and method for measuring instantaneous power using a magneto-optic Kerr effect sensor

An apparatus for measuring instantaneous power using a magnetic field sensor, said apparatus comprising:

• a light source;
• a first polarizer for receiving light from said light source, said first polarizer allowing light having a first polarization to pass therethrough;
• a magnetic field sensor for receiving light having said first polarization from said first polarizer, said magnetic field sensor having optical properties which change in relation to variations in the intensity of an external magnetic field generated by a current flowing through a power cable, said magnetic field sensor specularly reflecting said light from said first polarizer in accordance with said changing optical properties;
• a second polarizer for receiving light specularly reflected from said magnetic field sensor, said second polarizer attenuating the intensity of said light specularly reflected from said magnetic field sensor having said first polarization;
• a photoconductive detector for receiving light from said second polarizer, said photoconductive detector having conductivity properties which change in relation to variations in the intensity of said light from said second polarizer;
• and
• circuitry for sampling a voltage flowing through said power cable, said voltage being used to bias said photoconductive detector.