Shielded Fluxgates for Open-Loop Current Transducers; Measuring High Flux Densities Fast

A novel concept to measure magnetic flux densities up to more than one hundred milliteslas is presented. It offers constant and stable sensitivity as well as low offset over a wide temperature range together with a short response time of some microseconds. The magnetic induction sensor consists of a tiny fluxgate (1.7 times 1.1 times 0.9 mm
³
) which is mounted in a precision magnetic shield having a constant shielding effect. This assembly is connected to an electronic circuit providing excitation of the fluxgate and a feedback current for local flux density compensation.