An electronic magnetometer

Abstract

A probe unit containing a miniature cathode-ray tube is brought into the field to be measured, and the resulting deflexion of the electron beam is automatically compensated by a voltage applied to the electrostatic deflecting plates. This voltage is proportional to the magnetic field for steady fields and for fields changing at not more than 10 kc/s. Using standard components an output of 12.5 V/oersted is obtainable with a drift of about 1 mV/min. The smallest field measurable is thus 10-4 oersted.