Development of Micro-size Search Coil Magnetometer for Magnetic Field Distribution Measurement

Abstract

For the measurement of the magnetic field distribution with high spatial resolution and high accuracy, the magnetic field sensing probe must be non-magnetic, but the MFM probe and sub-millimeter-meter size Hall probe use a ferromagnetic tip and block, respectively, to increase the sensitivity. To overcome this drawback, we developed a micro-size search coil magnetometer which consists of a single turn search coil, Terfenol-D actuator, scanning system, and control software. To reduce the noise generated by the stray ac magnetic field of the actuator driving coil, we employed an even function λ-H magnetostriction curve and lock-in technique. Using the developed magnetometer, we were able to measure the magnetic field distribution with a magnetic field resolution of 1 mT and spatial resolution of 0.1 mm × 0.2 mm at a coil vibration frequency of 1.8 kHz.

Study on the Development of Demagnetizing System for Hub Bearing Inner of Automobile

“…However, demagnetizing devices applied in industrial fields are not able to frequently detect residual magnetic on processed objects since technology for estimating magnetic of the product is not integrated. In addition, as the consistent demagnetizer is always applied to remove residual magnetic, a significant amount of electricity is consumed on a small amount of magnetic [3][4][5]. In addition, due to heat from magnetic saturation on demagnetizer, the amount of residual magnetic tends to increase over targeted amount as time passes by.…”

Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

“…In particular, it is impossible to measure BP and pulse without an unpleasant oppressive feeling due to the use of pressurization, and accuracy is remarkably low. If the accuracy of vital information is ambiguous, it cannot be used as baseline data to understand medical activity, so accurate measurements are a required precondition for the U-health industry [ 3 , 4 ].…”

Fabrication and Characterization of a Wrist Wearable Cuffless Pulsimeter by Using the Hall Effect Device

“…Traditional technology using a radially arterial pulsimeter is a conceptually materialized measuring device of pressure and pulse to portable device as watch or ring [1,2]. Also, it is difficult to measure data accurately to use a traditional taking pulse method when it moves, because it is difficult to hold its sensor and it makes static even though the traditional taking pulse method can measure blood pressure and pulse by holding its pulse wave sensor at aorta radialis.…”