Construction of a Direct Current Magnetometer

In order to display magnetic signals obtained from a magneto-resistance sensor, a direct current magnetometer was designed and its circuit was constructed. The magnetic fields measured by the home-made magnetometer, which showed good functions of automatic ranging, analog output, and vector sensing, were well agreed with those by commercial MAG-01 magnetometer. The measurement range of the magnetometer was to 1.999 mT, the resolution was -132 dB within 1 Hz bandwidth and the measured magnetic fields could be displayed with -digit LED.