CURRENT SENSOR USING RESONANCE INDICATING MEGNETOMETER

摘要

PURPOSE: To conduct measuring of a random strength of a current with a high operating characteristic and a high accuracy by exciting a resonance by a first magnetic means disposed adjacent to a sample, detecting the excited resonance and making a voltage expression thereof. CONSTITUTION: A current sensor comprises a magnetic circuit CM having a gap ER and a resonance indicating magnetometer MD which is provided with a coil 4 which encircles a sample and the sample 2 which is made of a material having an electrically resonance spin. The sample 2 is disposed in the gap ER and is exposed to a polarization magnetic field Hb which is parallel to the magnetic feed Hlex A high frequency oscillator excites a resonance together with a measuring bridge 8 and the coil 4. A high frequency signal obtained from an output of the bridge 8 is amplified by an amplifier 16 and the reference signal is inputted to a balanced mixer 18. An output voltage V2 of an integrator 31 is proportional to a current to be measured. An auxiliary magnetic field generated by a measured current generates an error signal and this error signal is superposed to a resonance curve so as to cancel a magnetic field generated by the measured current.