Simple Null-Indicating Saturable-Core Magnetometer for the Detection of Static Magnetic Fields

Abstract

A simple null-indicating saturable-core magnetometer has been designed as a completely self-contained unit requiring no associated equipment other than a VTVM or oscilloscope for monitoring the output. The device is useful for detecting static magnetic fields of the order of 0.1 millioersted. It was built to enable the establishment of a near zero magnetic field over a limited volume by means of pairs of Helmholtz coils. A Hartshorn bridge circuit is employed to cancel out the fundamental of the driving frequency in the output portion of the circuit. A test signal incorporated into the instrument affords a check on the sensitivity.