OPTOELECTRONIC METER OF PERMANENT MAGNETIC FIELDS AND DIRECT CURRENTS Russian patent published in 1995 - IPC

FIELD: instruments. SUBSTANCE: device uses Faraday's effect in light-sensitive magnetic film 4 having surface anisotropy. Degree of magnetization of this magnetic film depends on external magnetic fields. Film 4 is positioned on optical contact surface of hypotenuse of prism 3. Polarized light from light-emitting diode 1 is modulated in the film according to its degree of magnetization. Beams with orthogonal polarization are separated by analyzer 5 and are detected by photo diodes 6 an d7 which are connected to differential amplifier 8. This signal is filtered at low-pass filter 9 and is received by comparison unit 10 where it is compared to zero. Signal from output of comparison unit 10 serves as control signal of current amplifier 11 which supplies coil 13. Coil 13 serves for compensation of external magnetic fields. Measured value is judged by level of current running through coil. Effect of coercion in film 4 is eliminated by introduced second coil 12 which is connected to high-frequency signal oscillator 14. EFFECT: measuring magnetic fields and currents of power supply units. 1 dwg