Self-Oscillator Made by Using a Magnetoelastic Ribbon: Application to a Compact Remote Viscosity and Density Sensor

Abstract

This paper describes the use of a self-oscillator made by employing a magnetoelastic ribbon resonator as a remote viscosity and density sensor. The magnetoelastic ribbon was placed between a drive coil and a pickup coil. The vibration of the magnetoelastic ribbon was detected as an induced voltage by the pickup coil. The induced voltage was amplified (with an amplifier) and fed back to the drive coil, whose magnetic field increased the amplitude of the ribbon vibration. As a result, a self-oscillator was realized when a one-wavelength longitudinal elastic standing wave was excited on the ribbon. We demonstrated that the inverse of Q of the self-oscillator was proportional to the square root of the product of the viscosity and density of the surrounding liquids. These results suggest that this self-oscillator is a promising candidate for use as a compact remote viscosity and/or density sensor.