Features

　　Three measuring coils,a core and integrated circuit package

　　Three orthogonal measurement coils together with one permeable core

　　Three components to be measured simultaneously at one point in space

　　Internal temperature sensor for thermal modeling

　　Description

　　HJMAG902 three-axis magnetometer has three orthogonal coils,which construct three measurement axes:X,Y and Z.There is a permeable core in the center of the three coils for operation with three coils.The three coils and the core construct a 3-axis fluxgate magnetometer,which can be used for magnetic field measuring at a point in space--measuring three components of magnetic field:X,Y and Z.

　　Three-axis fluxgate magnetometer periodically makes magnetic core in permeable state and saturation state.In permeable state,magnetic core makes magnetic line converged to the core,and it makes magnetic flux in detection coil more;in saturation state,magnetic core makes magnetic line diverged from core,in one period the state of magnetic core changes four times and this change shall cause induction voltage:Pickup 1,Pickup 2,Pickup 3,and Pickup 4.High initial permeability of the core,the time which permeable state transition to saturation state in short,the voltage pulses width is narrow induced in four peaks,ease of full-wave phase-sensitive rectifier,a good sensitivity to increase the open loop.

 

 

　　The fluxgate circuit is mainly composed of excitation circuit and detection circuit.The excitation circuit provides excitation coil with excitation current,which is composed of oscillator,power amplification drive circuit.The detection circuit is composed of amplifying circuit,phase-sensitive rectifier,filter circuit,integral circuit and feedback circuit.The detection circuit carries out sampling and integration on voltage pulse,and provides feed-back current to detection coil according to the after-integration voltage value.Then this current induces magnetic field with this feed-back current,and the induced magnetic field shall offset the earth’s magnetic field component along this axis.The detection circuit has three channels,which make magnetic field in three detection coils to be zero.So measurement of 3-axis fluxgate magnetometer HJMAG902 is a close-loop test,and the feedback currents in three detection coils should accurately correspond with the three components of magnetic field.

 

 

　　Dimensions

 

 

 

　　Performance Characteristics